Coating composition having anti-reflective and anti-fogging properties

A coating composition which imparts anti-reflection and anti-fogging properties to a substrate having at least one surface coated therewith, the coating composition comprising:

• (a) an inorganic metal oxide sol capable of forming a porous inorganic metal oxide network which provides anti-reflection properties to a substrate;
• (b) a surfactant having a solubility in water of less than about 10 percent by weight at 23.degree. C. and comprised of at least one hydrophobic group and at least one hydrophilic anionic group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, --CO.sub.2.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, P(O)(O.sup.-).sub.2, --P(O.sup.-).sub.2, --OP(O.sup.-).sub.2, (--SO.sub.2).sub.2 N.sup.-, --SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.+ (R).sub.2 (CH.sub.2).sub.x L', wherein R is hydrogen, an alkyl group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms;
• x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, SO.sub.2 O.sup.+, (--O).sub.2 P(O)O.sup.+, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2 and --CO.sup.-.sub.2 ;
• and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li.sup.+, Ca.sup.+2, Mg.sup.+2, Sr.sup.+2, Al.sup.+3, and R"A", wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N.sup.+ R.sub.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N.sup.+ B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur;
• the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• and wherein the surfactant has at least one of the following properties:
• (1) a melting point greater than 20.degree. C.;
• or
• (2) is capable of being covalently bonded to metal oxide;
• the surfactant being present in amounts necessary to provide anti-fogging properties to substrates coated on at least one surface with the coating composition and having a porous inorganic metal oxide network of uniform average highness, but not sufficient to reduce the anti-reflection properties provided by the inorganic metal oxide to less than 3% greater than the uncoated substrate, measured by percent transmission of 550 nm light.

An article comprising a substrate which is transparent or translucent to visible light coated with

• (a) a porous inorganic metal oxide network of uniform average thickness which provides anti-reflection properties to the substrate;
• and
• (b) a surfactant having a solubility in water of less than 10 percent by weight at 23.degree. C. and comprised of at least one hydrophobic group and at least one hydrophilic anionic group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, --CO.sub.2.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.2).sub.2, --P(O.sup.-).sub.2, --OP(O.sup.+).sub.2, (--SO.sub.2).sub.2 N.sup.-, <SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.+ (R).sub.2 (CH.sub.2).sub.x L', wherein R is hydrogen, an alkyl group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms, x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O;
• --SO.sub.2 O, (--O).sub.2 P(O)O.sup.-, --OP(O)(O).sup.-.sub.2, --P(O)(O.sup.-).sub.2 and CO.sup.-.sub.2 ;
• and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K', Li.sup.+, Ca.sup.+2, Mg.sup.+2, Sr.sup.+2, Al.sup.+3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N.sup.+ R.sub.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N.sup.+ B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur;
• the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• and wherein the surfactant has at least one of the following properties:
• (1) a melting point grater than 20.degree. C.;
• or
• (2) is capable of being covalently bonded to metal oxide;
• which coated substrate when coated on at least one surface with the inorganic metal oxide network in contact with the surfactant exhibits;
• 1) a drop diameter of at least 4 mm when tested in accordance with the Wetting Test described herein;
• and
• 2) a percent transmission at 550 nm which is at least 3 percent greater than that of the uncoated substrate.

An eye shield comprising a substrate which is transparent or translucent to visible light coated with

• (a) a porous inorganic metal oxide network of uniform average thickness which provides anti-reflection properties to the substrate;
• and
• (b) a surfactant having a solubility in water of less than about 1 percent by weight at 23.degree. C. and comprised of at least one hydrophobic group and at least one hydrophilic anionic group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, --CO.sub.2.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2, --P(O.sup.-).sub.2, --OP(O.sup.-).sub.2, (--SO).sub.2 N, --SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.+ (R).sub.2 (CH.sub.2).sub.x L', wherein R is hydrogen, an alkyl group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms;
• x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2 and --CO.sup.-.sub.2 ;
• and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li.sup.+, Ca.sup.+2, Mg.sup.+2, Sr.sup.+2, Al.sup.+3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N.sup.+ R.sub.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N.sup.+ B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur;
• the cation selected such that lie net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• which coated substrate when coated on at least one surface with the inorganic metal oxide network in contact with the surfactant exhibits:
• 1) a drop diameter of at least 4 mm when tested in accordance with the Wetting Test described herein;
• and
• 2) a percent transmission at 550 nm which is at least 3 percent greater than that of the uncoated substrate.

A method of imparting anti-reflection and anti-fogging properties to a substrate, the method comprising the steps of:

• (a) providing a substrate;
• (b) preparing a coating composition comprising:
• (1) an inorganic metal oxide sol capable of forming a porous network which provides anti-reflection properties to a substrate;
• and
• (2) a surfactant having a solubility in water of less than about 1 percent by weight at 23.degree. C. and comprised of at least one hydrophobic group and at least one hydrophilic anionic group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, --CO.sub.2.sup.-, (--O).sub.2 P(O)(O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2, --P(O.sup.-).sub.2, --OP(O.sup.-).sub.2, (--SO.sub.2).sub.2 N.sup.-, --SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.+ (R).sub.2 (CH.sub.2).sub.x L', wherein R is hydrogen, an alkyl group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms;
• x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O).sup.-.sub.2, --P(O)(O.sup.-).sub.2 and --CO.sup.-.sub.2 ;
• and
• wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li.sup.+, Ca.sup.+2, Mg.sup.+2, Sr.sup.+2, Al.sup.+3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N+R.sub.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N.sup.+ B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur, the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• wherein the metal oxide and surfactant are present in the coating composition in amounts sufficient to provide the coated light transmissive substrate
• (1 ) with a drop diameter of at least about 4 mm when tested in accordance with the Wetting Test described herein;
• and
• (2) with a percent transmission at 550 nm which is at least 3 percent greater than that of the uncoated substrate;
• (c) applying the coating composition to at least one side of a substrate;
• and
• (d) drying the coating composition to produce a coated substrate having a porous inorganic metal oxide network of uniform average thickness.

An article comprising a substrate which is transparent or translucent to visible light coated with

• (a) a porous inorganic metal oxide network of uniform average thickness which provides anti-reflection properties to a substrate;
• and
• (b) a surfactant having a solubility in water of less than about 1 percent by weight at 23.degree. C. and comprised of at least one hydrophobic group and at least one hydrophilic anionic group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, --CO.sub.2.sup.+, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2, --P(O.sup.-).sub.2, --OP(O.sup.-).sub.2, (--SO.sub.2).sub.2 N.sup.-, --SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.+ (R).sub.2 (CH.sub.2).sub.x L', wherein R is hydrogen, an alkyl group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms;
• x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2 and --CO.sup.-.sub.2 ;
• and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li.sup.+, Ca.sup.+2, Mg.sup.+2, Sr.sup.+2, Al.sup.+3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N.sup.+ R.sup.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N.sup.+ B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur;
• the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• which coated substrate when coated on at least one surface with the inorganic metal oxide network in contact with the surfactant exhibits;
• (1) a drop diameter of at least 4 mm when tested in accordance with the Wetting Test described herein;
• and
• (2) a percent transmission at 550 nm which is at least 3 percent greater than that of the uncoated substrate;
• and
• wherein the article is packaged within a material which protects the article from environmental exposure.

A coating composition which imparts anti-reflection and anti-fogging properties to a substrate having at least one surface coated therewith, the coating composition comprising:

• (a) an aqueous or hydroalcoholic solvent system;
• (b) inorganic metal oxide particles;
• and
• (c) a surfactant present in an amount such that a dried coating formed from the coating composition comprises about 0.13 percent by weight to about 5 percent by weight of surfactant, wherein the surfactant is comprised of at least one hydrophobic group and at least one hydrophilic anionic group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, --CO.sub.2.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O(O.sup.-).sub.2, --P(O.sup.-).sub.2, --OP(O.sup.-).sub.2, (--SO.sub.2).sub.2 N.sup.-, --SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.+ (R).sub.2 (CH.sub.2).sub.x L', wherein R is hydrogen, an alkyl group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms;
• x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.+, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2 and --CO.sup.-.sub.2 ;
• and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li.sup.+, Ca.sup.+2, Mg.sup.+2, Sr.sup.+2, Al.sup.+3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N.sup.+ R.sub.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N+B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur;
• the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• wherein the coating composition when coated on at least one side of a light transmissive substrate and dried provides a coated substrate with:
• (1) a porous in organic metal oxide network of uniform average thickness;
• (2) a drop diameter of at least about 4 mm when tested in accordance with the Wetting Test described herein;
• and
• (3) a percent transmission at 550 nm which is at least 3 percent greater than that of the uncoated substrate.

A coating composition which imparts anti-reflection and anti-fogging properties to a substrate having at least one surface coated therewith, the coating composition comprising:

• (a) an aqueous or hydroalcoholic solvent system;
• (b) inorganic metal oxide particles;
• (c) a surfactant present in an amount such that a dried coating formed from the coating composition comprises about 0.13 percent by weight to about 5 percent by weight of surfactant, wherein the surfactant is comprised of at least one hydrophobic group and at least one hydrophilic anionic group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O.sup.+, --SO.sub.2 O.sup.-, --CO.sub.2.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O.sup.-).sub.2, --OP(O.sup.-).sub.2, (--SO.sub.2).sub.2 N.sup.+, --SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.4 (R).sub.2 (CH.sub.2).sub.x L' wherein R is hydrogen, an alkyl group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms;
• x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, SO.sub.2 O.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2 and --CO.sup.-.sub.2;
• and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li.sup.+, Ca.sup.+2, Mg.sup.+2, Sr.sup.+2, Al.sup.+3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about l to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N.sup.+ R.sub.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N.sup.+ B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur;
• the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• and wherein the surfactant has at least one of the following properties:
• (1) a melting point greater than 20.degree. C.;
• (2) a solubility in water of less than 10 percent by weight;
• or
• (3) is capable of being covalently bonded to metal oxide;
• the surfactant being present in amounts necessary to provide anti-fogging properties to substrates coated on at least one surface with the coating composition and having a porous inorganic metal oxide network of uniform average thickness, but not sufficient to reduce the anti-reflection properties provided by the inorganic metal oxide to less than 3% greater than the uncoated substrate, measured by percent transmission of 550 nm light.

A method of imparting anti-reflection and anti-fogging properties to a substrate, the method comprising the steps of:

• (a) providing a substrate;
• (b) preparing a coating composition comprising:
• (1) an aqueous or hydroalcoholic solvent system;
• (2) inorganic metal oxide particles;
• and
• (3) a surfactant present in an amount such that a dried coating formed from the coating composition comprises about 0.13 percent by weight to about 5 percent by weight of surfactant, wherein the surfactant is comprised of at least one hydrophobic group and at least one hydrophilic anionic, group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, --CO.sub.2.sup.-, (--O).sub.2 P(O)O.sup.'1, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2, --P(O.sup.-).sub.2, --OP(O.sup.-).sub.2, (--SO.sub.2).sub.2 N.sup.-, --SO.sub.2 N(R).sup.+, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.+ (R).sub.2 (CH.sub.2).sub.x L', wherein R is hydrogen, an alkyl group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms;
• x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O).sup.-.sub.2, --P(O)(O.sup.-).sub.2 and --CO.sup.-.sub.2 ;
• and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li.sup.+, Ca.sup.+2, Mg.sup.+2, Sr.sup.+2, Al.sup.+3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N.sup.+ R.sub.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N.sup.+ B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur;
• the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• wherein the metal oxide and surfactant are present in the coating composition in amounts sufficient to provide the coated light transmissive substrate
• (1) with a drop diameter of at least about 4 mm when tested in accordance with the Wetting Test described herein;
• and
• (2) with a percent transmission at 550 nm which is at least 3 percent greater than that of the uncoated substrate;
• (c) applying the coating composition to at least one side of a substrate;
• and
• (d) drying the coating composition to produce a coated substrate having a porous inorganic metal oxide network of uniform average thickness.

A coating composition which imparts anti-reflection and anti-fogging properties to a substrate having at least one surface continuously coated therewith, the coating composition comprising:

• (a) an aqueous or hydroalcoholic solvent system;
• (b) between about 1 percent by weight and about 5 percent by weight of inorganic metal oxide particles present in the form of a base stabilized sol;
• and
• (c) less than about 0.15 percent by weight of a surfactant having a solubility in water of less than about 10 percent by weight at 23.degree. C. and comprised of at least one hydrophobic group and at least one hydrophilic anionic group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, --CO.sub.2.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2, --P(O.sup.-).sub.2, --OP(O.sup.-).sub.2, (--SO.sub.2).sub.2 N.sup.-, --SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.+ (R).sub.2 (CH.sub.2).sub.x L', wherein R is hydrogen, an alkyl group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms;
• x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2 and --CO.sup.-.sub.2 ;
• and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li.sup.+, Ca.sup.+2, Mg.sup.+2, Sr.sup.+2, Al.sup.+3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N.sup.+ R.sub.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N.sup.+ B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur;
• the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms.

A coating composition which imparts anti-reflection and anti-fogging properties to a substrate having at least one surface coated therewith, the coating composition comprising:

• (a) an inorganic metal oxide sol capable of forming a porous inorganic metal oxide network which provides anti-reflective properties to a substrate;
• and
• (b) a surfactant having a solubility in water of less than about 10 percent by weight at 23.degree. C. and a melting point of greater than 20.degree. C., and is comprised of at least one hydrophobic group and at least one hydrophilic anionic group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, --CO.sub.2.sup.-, (--O).sub.3 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2, --P(O.sup.-).sub.2, --OP(O.sup.-).sub.2, (--SO.sub.2).sub.2 N.sup.-, --SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.+ (R).sub.2 (CH.sub.2).sub.x L', wherein R is hydrogen, an all group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms, x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2 and --CO.sup.-.sub.2 ;
• and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li.sup.+, Ca.sup.+2, Mg.sup.+2, Sr.sup.+2, Al.sup.+3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N.sup.+ R.sub.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N.sup.+ B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur;
• the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• wherein the coating composition when coated on at least one side of a light transmissive substrate and dried provides a coated substrate with:
• (1) a porous inorganic metal oxide network of uniform average thickness;
• (2) a drop diameter of at least about 4 mm when tested in accordance with the Wetting Test described herein;
• and
• (3) a percent transmission at 550 nm which is at least 3 percent greater than that of the uncoated substrate.

A coating composition which imparts anti-reflection and anti-fogging properties to a substrate having at least one surface coated therewith, the coating composition comprising:

• (a) an inorganic metal oxide sol capable of forming a porous inorganic metal oxide network which provides anti-reflective properties to a substrate;
• and
• (b) a surfactant having a solubility in water of less than about 10 percent by weight at 23.degree. C., is capable of being covalently bonded to the metal oxide, and is comprised of at least one hydrophobic group and at least one hydrophilic anionic group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, --CO.sub.2.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2, --P(O.sup.-).sub.2, --OP(O.sup.-).sub.2, (--SO.sub.2).sub.2 N.sup.-, --SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.+ (R).sub.2 (CH.sub.2).sub.x L', wherein R is hydrogen, an alkyl group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms;
• x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2 and --CO.sup.-.sub.2 ;
• and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li.sup.+, Ca.sup.+2, Mg.sup.+2, Sr.sup.+2, Al.sup.+3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N.sup.+ R.sub.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N.sup.+ B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur;
• the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• wherein the coating composition when coated on at least one side of a light transmissive substrate and dried provides a coated substrate with:
• (1) a porous inorganic metal oxide network of uniform average thickness;
• (2) a drop diameter of at least about 4 mm when tested in accordance with the Wetting Test described herein;
• and
• (3) a percent transmission at 550 nm which is at least 3 percent greater than that of the uncoated substrate.

A coating composition which imparts anti-reflection and anti-fogging properties to a substrate having at least one surface coated therewith, the coating composition comprising:

• (a) an inorganic metal oxide sol comprising particles capable of forming a porous inorganic metal oxide network which provides anti-reflective properties to a substrate;
• wherein the composition comprises about 1 to about 5 percent by weight of the inorganic metal oxide particles;
• and
• (b) less than 0.15 percent by weight of a surfactant having a solubility in water of less than about 10 percent by weight at 23.degree. C. and comprised of at least one hydrophobic group and at least one hydrophilic anionic group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, --CO.sub.2.sup.-, (--O).sub.2 P(O)O.sup.'1, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2, --P(O.sup.-).sub.2, --OP(O.sup.-).sub.2, (--SO.sub.2).sub.2 N.sup.-, --SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 (C.sup.- H, and --N.sup.+(R).sub.2 (CH.sub.2).sub.x L', wherein R is hydrogen, an alkyl group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms;
• x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2 and --CO.sup.-2 ;
• and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li.sup.+, Ca.sup.+, Mg.sup.+2, Sr.sup.+2, Al.sup.+3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and. R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N.sup.+ R.sub.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N.sup.+ B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur;
• the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• wherein the coating composition when coated on at least one side of a light transmissive substrate and dried provides a coated substrate wit:
• (1) a porous inorganic metal oxide network of uniform average thickness;
• (2) a drop diameter of at least about 4 mm when tested in accordance with the Wetting Test described herein;
• and
• (3) a percent transmission at 550 nm which is at least 3 percent greater than that of the uncoated substrate.

A method of imparting anti-reflection and anti-fogging properties to a substrate, the method comprising the steps of:

• (a) providing a substrate;
• (b) preparing a coating composition comprising:
• (1) an inorganic metal oxide sol capable of forming a porous network which provides anti-reflection properties to a substrate;
• and
• (2) a surfactant having a solubility in water of less than about 10 percent by weight at 23.degree. C. and comprised of at least one hydrophobic group and at least one hydrophilic anionic group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O--, --SO.sub.2 O.sup.-, --CO.sub.2.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2, --P(O.sup.-).sub.2,--OP(O.sup.31 ).sub.2, (--SO.sub.2).sub.2 N.sup.-, --SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.+ (R).sub.2 (CH.sub.2).sub.x L', wherein R is hydrogen, an alkyl group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms;
• x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O).sup.-.sub.2, --P(O)(O.sup.-).sub.2 and --CO.sup.-.sub.2 ;
• and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li.sup.+, Ca.sup.+2, Mg'.sup.2, Sr.sup.+2, Al.sup.+3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N.sup.+R.sub.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N'B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen nitrogen or sulfur;
• the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• wherein the metal oxide and surfactant are present in the coating composition in amounts sufficient to provide the coated light transmissive substrate
• (1) with a drop diameter of at least about 4 mm when tested in accordance with the Wetting Test described herein;
• and
• (2) with a percent transmission at 550 nm which is at least 3 percent greater than that of the uncoated substrate;
• (c) applying the coating composition to at least one side of a substrate;
• and
• (d) drying the coating composition to produce a coated substrate having a porous inorganic metal oxide network of uniform average thickness which varies by less than about 200 Angstroms.

A method of imparting anti-reflection and anti-fogging properties to a substrate, the method comprising the steps of:

• (a) providing a substrate having two major surfaces;
• (b) preparing a coating composition comprising:
• (1) an inorganic metal oxide sol capable of forming a porous network which provides anti-reflection properties to a substrate;
• and
• (2) a surfactant having a solubility in water of less than about 10 percent by weight at 23.degree. C. and comprised of at least one hydrophobic group and at least one hydrophilic anionic group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.', --CO.sub.2.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.- .sub.2, --P(O)(O.sup.-).sub.2, --P(O.sup.31).sub.2, --OP(O.sup.-).sub.2, (--SO.sub.2).sub.2 N.sup.-, --SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.+ (R).sub.2 (CH.sub.2).sub.x L', wherein R is hydrogen, an alkyl group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms;
• x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.- (--O).sub.2 P(O)O.sup.-, --OP(O)(O).sup.-.sub.2, --P(O)(O.sup.-).sub.2 and --CO.sup.-.sub.2 ;
• and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li', Ca.sup.+2, Mg.sup.+2, Sr.sup.+2, Al.sup.+3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N.sup.+ R.sub.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N.sup.+ B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur;
• the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• wherein the metal oxide and surfactant are present in the coating composition in amounts sufficient to provide the coated light transmissive substrate
• (1) with a drop diameter of at least about 4 mm when tested in accordance with the Wetting Test described herein;
• and
• (2) with a percent transmission at 550 nm which is at least 3 percent greater than that of the uncoated substrate;
• (c) applying the coating composition to both major surfaces of the substrate;
• and
• (d) drying the coating composition to produce a coated substrate having a porous inorganic metal oxide network of uniform average thickness.

A method of imparting anti-reflection and anti-fogging properties to a substrate, the method comprising the steps of:

• (a) providing a substrate;
• (b) preparing a coating composition comprising:
• (1) an inorganic metal oxide sol capable of forming a porous network which provides anti-reflection properties to a substrate;
• and
• (2) a surfactant having a solubility in water of less than about 10 percent by weight at 23.degree. C. and comprised of at least one hydrophobic group and at least one hydrophilic anionic group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.7, --SO.sub.2 O.sup.-, --CO.sub.2.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2, --P(O.sup.-).sub.2, --OP(O.sup.-).sub.2, (--SO.sub.2).sub.2 N.sup.-, --SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.+ (R).sub.2 (CH.sub.2).sub.x L', wherein R is hydrogen, an alkyl group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms;
• x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, (--O.sub.2 P(O)O.sup.-, --OP(O)(O).sup.-.sub.2, --P(O)(O.sup.-).sub.2 and --CO.sup.-.sub.2 ;
• and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li.sup.+, Ca.sup.+2, Mg.sup.+2, Sr.sup.+2, Al.sup.+3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N.sup.+ R.sub.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N.sup.+ B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur;
• the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• wherein the metal oxide and surfactant are present in the coating composition in amounts sufficient to provide the coated light transmissive substrate
• (1) with a drop diameter of at least about 4 mm when tested in accordance with the Wetting Test described herein;
• and
• (2) with a percent transmission at 550 nm which is at least 3 percent greater than that of the uncoated substrate;
• (c) applying the coating composition to at least one side of the substrate by roll coating with an air knife;
• and
• (d) drying the coating composition to produce a coated substrate having a porous inorganic metal oxide network of uniform average thickness.

A method of imparting anti-reflection and anti-fogging properties to a substrate, the method comprising the steps of:

• (a) providing a substrate;
• (b) preparing a coating composition comprising:
• (1) an inorganic metal oxide sol capable of forming a porous network which provides anti-reflection properties to a substrate;
• and
• (2) a surfactant having a solubility in water of less than about 10 percent by weight at 23.degree. C. and comprised of at least one hydrophobic group and at least one hydrophilic anionic group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, --CO.sub.2.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sub.o.sup.-).sub.2, --OP(O.sup.-).sub.2, (--SO.sub.2).sub.2 N.sup.-, --SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.+ (R).sub.2 (Ch.sub.2).sub.x L', wherein R is hydrogen, an alkyl group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms;
• x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O).sup.-.sub.2, --P(O)(O.sup.-).sub.1 an --CO.sup.-.sub.2 ;
• and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li.sup.+, Ca.sup.+2, Mg.sup.+2, Sr.sup.+2, Al.sup.+3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N.sup.+ R.sub.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N.sup.+ B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur;
• the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• wherein the metal oxide and surfactant are present in the coating composition in amounts sufficient to provide the coated light transmissive substrate
• (1) with a drop diameter of at least about 4 mm when tested in accordance with the Wetting Test described herein;
• and
• (2) with a percent transmission at 550 nm which is at least 3 percent greater than that of the uncoated substrate;
• (c) applying the coating composition to at least one side of the substrate using a rotogravure process;
• and
• (d) drying the coating composition to produce a coated substrate having a porous inorganic metal oxide network of uniform average thickness.

A method of imparting anti-reflection and anti-fogging properties to a substrate, the method comprising the steps of:

• (a) providing a substrate;
• (b) preparing a coating composition comprising:
• (1) an inorganic metal oxide sol capable of forming a porous network which provides anti-reflection properties to a substrate;
• and
• (2) a surfactant having a solubility in water of less than about 10 percent by weight at 23.degree. C. and comprised of at least one hydrophobic group and at least one hydrophilic anionic group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O.sup.-1, --SO.sub.2 O.sup.-, --CO.sub.2.sup.-1, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2, --P(O.sup.-).sub.2, --OP(O.sup.-).sub.2, (--SO.sub.2).sub.2 N.sup.-, --SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.+ (R).sub.2 (CH.sub.2).sub.x L', wherein R is hydrogen, an alkyl group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms;
• x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, (--O).sub.2 P(O)O, --OP(O)(O).sup.-.sub.2, --P(O)(O.sup.-).sub.2 and --CO.sup.-.sub.2 ;
• and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li.sup.+, Ca.sup.+.sup.2, Mg.sup.+2, Sr.sup.+.sup.2, Al.sup.+3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N.sup.+ R.sub.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N.sup.+ B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur;
• the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• wherein the metal oxide and surfactant are present in the coating composition in amounts sufficient to provide the coated light transmissive substrate
• (1) with a drop diameter of at least about 4 mm when tested in accordance with the Wetting Test described herein;
• and
• (2) with a percent transmission at 550 nm which is at least 3 percent greater than that of the uncoated substrate;
• (c) applying the coating composition to at least one side of a substrate;
• and
• (d) drying the coating composition to produce a coated substrate having a continuous, porous network of inorganic metal oxide particles of uniform average thickness.

A coating composition which imparts anti-reflection and anti-fogging properties to a substrate having at least one surface coated therewith, the coating composition comprising:

• (a) an inorganic metal oxide sol capable of forming a porous inorganic metal oxide network which provides anti-reflective properties to a substrate;
• and
• (b) a surfactant having a solubility in water of less than about 0.1 percent by weight at 23.degree. C. and comprised of at least one hydrophobic group and at least one hydrophilic anionic group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, --CO.sub.2.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2, --P(O.sup.-).sub.2, --OP(O.sup.-).sub.2, (--SO.sub.2).sub.2 N.sup.-, --SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.+ (R).sub.2 (CH.sub.2).sub.x L', wherein R is hydrogen, an alkyl group which is unsubstituted or substituted wit atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms;
• x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2 and --CO.sup.-.sub.2 ;
• and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li.sup.+, Ca.sup.+2, Mg.sup.+2, Sr.sup.+2, Al.sup.+3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N.sup.+ R.sub.3, a guanidinium ion optionally substituted with oxygen nitrogen or sulfur atoms, or N.sup.+ B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur;
• the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• wherein the coating composition when coated on at least one side of a light transmissive substrate and dried provides a coated substrate with:
• (1) a porous inorganic metal oxide network of uniform average thickness;
• (2) a drop diameter of at least about 4 mm when tested in accordance with the Wetting Test described herein;
• and
• (3) a percent transmission at 550 nm which is at least 3 percent greater than that of the uncoated substrate.

A coating composition which imparts anti-reflection and anti-fogging properties to a substrate having at least one surface coated therewith, the coating composition comprising:

• (a) a base stabilized inorganic metal oxide sol capable of forming a porous inorganic metal oxide network which provides anti-reflective properties to a substrate;
• and
• (b) a surfactant having a solubility in water of less than about 10 percent by weight at 23.degree. C. and comprised of at least one hydrophobic group and at least one hydrophilic anionic group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, --CO.sub.2.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2, --P(O.sup.-).sub.2, --OP(O.sup.-).sub.2, (--SO.sub.2).sub.2 N.sup.-, --SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.+ (R).sub.2 (CH.sub.2).sub.x L', wherein R is hydrogen, an alkyl group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms;
• x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2 and --CO.sup.-.sub.2 ;
• and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li.sup.+, Ca.sup.+2, Mg.sup.+2, Sr.sup.+2, Al.sup.+3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N.sup.+ R.sub.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N.sup.+ B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur;
• the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• wherein the coating composition when coated on at least one side of a light transmissive substrate and dried provides a coated substrate with:
• (1) a porous inorganic metal oxide network of uniform average thickness;
• (2) a drop diameter of at least about 4 mm when tested in accordance with the Wetting Test described herein;
• and
• (3) a percent transmission at 550 nm which is at least 3 percent greater than that of the uncoated substrate.

A coating composition which imparts anti-reflection and anti-fogging properties to a substrate having at least one surface coated therewith, the coating composition comprising:

• (a) a base stabilized inorganic metal oxide sol capable of forming a porous inorganic metal oxide network which provides anti-reflection properties to a substrate;
• (b) a surfactant having a solubility in water of less than about 10 percent by weight at 23.degree. C. and comprised of at least one hydrophobic group and at least one hydrophilic anionic group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup. , --CO.sub.2.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2, --P(O.sup.-).sub.2, --OP(O.sup.-).sub.2, (--SO.sub.2).sub.2 N.sup.-, --SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.+ (R).sub.2 (CH.sub.2).sub.x L', wherein R is hydrogen, all alkyl group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms;
• x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, SO.sub.2 O.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2 and --CO.sup.-.sub.2, and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li.sup.+, Ca.sup.+2, Mg.sup.+2, Sr.sup.+2, Al.sup.+3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, A.sup.+ is N.sup.+R.sub.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N.sup.+ B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur;
• the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• and wherein the surfactant has at least one of the following properties:
• (1) a melting point greater than 20.degree. C.;
• or
• (2) is capable of being covalently bonded to metal oxide, the surfactant being present in amounts necessary to provide anti-fogging properties to substrates coated on at least one surface with the coating composition and having a porous inorganic metal oxide network of uniform average thickness, but not sufficient to reduce the anti-reflection properties provided by the inorganic metal oxide to less than 3% greater than the uncoated substrate, measured by percent transmission of 550 nm light.

A method of imparting anti-reflection and anti-fogging properties to a substrate, the method comprising the steps of:

• (a) providing a substrate;
• (b) preparing a coating composition comprising:
• (1) a base stabilized inorganic metal oxide sol capable of forming a porous network which provides anti-reflection properties to a substrate;
• and
• (2) a surfactant having a solubility in water of less than about 10 percent by weight at 23.degree. C. and comprised of at least one hydrophobic group and at least one hydrophilic anionic groups wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, --CO.sub.2.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2, --P(O.sup.-).sub.2, --OP(O.sup.-).sub.2, (--SO.sub.2).sub.2 N.sup.-, --SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.+ (R).sub.2 (CH.sub.2).sub.x L', wherein R is hydrogen, an alkyl group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms;
• x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, (--O).sub.2)P(O)O.sup.-, --OP(O)(O).sup.-.sub.2, --P(O)(O.sup.-).sub.2 and --CO.sup.-.sub.2 ;
• and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li.sup.+, Ca'.sup.2, Mg.sup.+2, Sr.sup.+, Al.sup.+3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N.sup.+ R.sub.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N'B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur;
• the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• wherein the metal oxide and surfactant are present in the coating composition in amounts sufficient to provide the coated light transmissive substrate
• (1) with a drop diameter of at least about 4 mm when tested in accordance with the Wetting Test described herein;
• and
• (2) with a percent transmission at 550 nm which is at least 3 percent greater than that of the uncoated substrate;
• (c) applying the coating composition to at least one side of a substrate;
• and
• (d) drying the coating composition to produce a coated substrate having a porous inorganic metal oxide network of uniform average thickness.

A method of imparting anti-reflection and anti-fogging properties to a substrate, the method comprising the steps of:

• (a) providing a substrate;
• (b) preparing a first coating composition comprising an inorganic metal oxide sol capable of forming a porous network which provides anti-reflection properties to a substrate;
• (c) preparing a second coating composition comprising a surfactant having a solubility in water of less than about 1 percent by weight at 23.degree. C. and comprised of at least one hydrophobic group and at least one hydrophilic anionic group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, --CO.sub.2.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2, --P(O.sup.-).sub.2, --OP(O.sup.-).sub.2, (--SO.sub.2).sub.2 N.sup.-, --SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.+ (R).sub.2 (CH.sub.2).sub.x L', wherein R is hydrogen, an alkyl group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms;
• x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O).sup.-.sub.2, --P(O)(O.sup.-).sub.2, --CO.sup.-.sub.2 ;
• and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li.sup.+, Ca.sup.+2, Mg.sup.+2, Sr.sup..sup.2, Al.sup.+3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N+R.sub.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N.sup.+ B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur;
• the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• wherein the substrate is light transmissive and the amount of metal oxide and surfactant applied to the substrate is sufficient to provide the coated substrate with
• (1) a porous inorganic metal oxide network of uniform average thickness;
• (2) a drop diameter of at least about 4 mm when tested in accordance with the Wetting Test described herein;
• and
• (3) a percent transmission at 550 nm which is at least 3 percent greater than that of the uncoated substrate;
• (d) applying either the first or second coating composition to at least one side of the substrate;
• (e) allowing the coating applied in step (d) to dry;
• (f) applying the coating composition not applied in step (d) to the coating applied in step (d) on at least one side of the substrate;
• and
• (g) allowing the coating applied in step (f) to dry.

A method of imparting anti-reflection and anti-fogging properties to a substrate, the method comprising the steps of:

• (a) providing a substrate;
• (b) preparing a first coating composition comprising inorganic metal oxide particles;
• (c) preparing a second coating composition comprising a surfactant comprised of at least one hydrophobic group and at least one hydrophilic anionic group, wherein:
• (i) the hydrophilic anionic group comprises an anion selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, --CO.sub.2.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O.sup.-).sub.2, --P(O)(O.sup.-).sub.2, --P(O.sup.-).sub.2, --OP(O.sup.-).sub.2, (--SO.sub.2).sub.2 N.sup.-, --SO.sub.2 N(R).sup.-, (--SO.sub.2).sub.2 C.sup.- H, and --N.sup.+ (R).sub.2 (CH.sub.2).sub.x L',
• wherein R is hydrogen, an alkyl group which is unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen and sulfur, or an alkylene carboxyl group, which alkyl or alkylene carboxyl group comprises about 1 to 10 carbon atoms;
• x is 1 to 4;
• and L' is selected from the group consisting of --OSO.sub.2 O.sup.-, --SO.sub.2 O.sup.-, (--O).sub.2 P(O)O.sup.-, --OP(O)(O).sup.-.sub.2, --P(O)(O.sup.-).sub.2 and --CO.sup.-.sub.2 ;
• and wherein each anionic group is associated with or covalently bound to at least one cation, which cation is selected from the group consisting of H.sup.+, Na.sup.+, K.sup.+, Li.sup.+, Ca.sup.+2, Mg.sup.+2, Sr.sup.+2, Al.sup.++3, and R"A.sup.+, wherein R" is R or R' wherein R is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbon atoms, and R' is covalently bonded to the surfactant molecule and is an alkyl bridging group of 1 to 10 carbon atoms, and A.sup.+ is N.sup.+ R.sub.3, a guanidinium ion optionally substituted with oxygen, nitrogen or sulfur atoms, or N.sup.+ B wherein B comprises 3 to 7 atoms selected from the group consisting of carbon, nitrogen, sulfur and oxygen atoms which complete the nitrogen containing heterocyclic ring;
• and wherein any R or R' group may be unsubstituted or substituted with atoms independently selected from the group consisting of oxygen, nitrogen or sulfur;
• the cation selected such that the net charge of the surfactant molecule is neutral;
• and
• (ii) wherein the hydrophobic group comprises a hydrocarbon chain comprising at least 4 carbon atoms, or a perfluorinated radical comprising at least 3 carbon atoms;
• and wherein the surfactant has at least one of the following properties:
• (1) a melting point greater than 20.degree. C.;
• or
• (2) is capable of being covalently bonded to metal oxide;
• wherein the substrate is light transmissive and the amount of metal oxide and surfactant applied to the substrate is sufficient to provide the coated substrate with
• (1) a porous inorganic metal oxide network of uniform average thickness;
• (2) a drop diameter of at least about 4 mm when tested in accordance with the Wetting Test described herein;
• and
• (3) a percent transmission at 550 nm which is at least 3 percent greater than that of the uncoated substrate;
• (d) applying either the first or second coating composition to at least one side of the substrate;
• (e) allowing the coating applied in step (d) to dry;
• (f) applying the coating composition not applied in step (d) to the coating applied in step (d) on at least one side of the substrate;
• and
• (g) allowing the coating applied in step (f) to dry.