Salt-free composite marking based on chiral liquid crystal precursors comprising chiral acrylate dopants

A method of providing a marking on a substrate, wherein the method comprises:

• a) applying onto a surface of a substrate which carries a modifying resin made from one or more polymerizable monomers comprising an average of at least one ether functionality (—C—O—C—) per polymerizable group in one or more areas of the surface of the substrate a salt-free curable chiral liquid crystal precursor composition comprising (i) one or more nematic compounds A and (ii) one or more chiral dopant compounds B which are capable of giving rise to a cholesteric state of the chiral liquid crystal precursor composition and are of formula (I):
• wherein:
• R1, R2, R3, and R4 each independently denote C1-C6 alkyl and C1-C6 alkoxy;
• A1 and A2 each independently denote a group of formula —[(CH2)y—O]z—C(O)—CH═CH2;
• m, n, o, and p each independently denote 0, 1, or 2;
• y denotes 0, 1, 2, 3, 4, 5, or 6;
• and
• z equals 0 if y equals 0 and z equals 1 if y equals 1 to 6;
• in such a way that the composition covers at least a part of the one or more areas carrying the modifying resin and also covers at least one area of the surface that does not carry the modifying resin,
• b) heating the applied composition to bring same to a chiral liquid crystal state;
• and
• c) curing the composition in the chiral liquid crystal state;
• and wherein the modifying resin shifts the position of the selective reflection band exhibited by the cured chiral liquid crystal precursor composition on the substrate in the one or more areas in which it is present.

A method of changing a position of a selective reflection band exhibited by a cured chiral liquid crystal precursor composition, wherein the composition is salt-free and comprises (i) one or more nematic compounds A and (ii) one or more chiral dopant compounds B which are capable of giving rise to a cholesteric state of the chiral liquid crystal precursor composition and are of formula (I):

• wherein:
• R1, R2, R3, and R4 each independently denote C1-C6 alkyl and C1-C6 alkoxy;
• A1 and A2 each independently denote a group of formula —[(CH2)y—O]z—C(O)—CH═CH2;
• m, n, o, and p each independently denote 0, 1, or 2;
• y denotes 0, 1, 2, 3, 4, 5, or 6;
• and
• z equals 0 if y equals 0 and z equals 1 if y equals 1 to 6;
• and wherein the method comprises contacting the composition with a modifying resin which is made from one or more polymerizable monomers comprising an average of at least one ether functionality (—C—O—C—) per polymerizable group and is capable of changing a position of a selective reflection band exhibited by the salt-free cured chiral liquid crystal precursor composition.