Block copolymers

A method of making a porous polymer article with enhanced hydrophilicity comprising the steps of:

• providing a casting solution which includes
• (i) 0.1-50 weight percent of a block copolymer having the formula:
• R--(OCH.sub.2 CH.sub.2).sub.n --X--Y (I)
• wherein R is C.sub.1-20 alkyl, C.sub.7-20 alkylaryl, C.sub.7-20 arylalkyl, or C.sub.1-20 perfluoroalkyl;
• n is between 20 and 500;
• X is --Z.sup.1 --(OAr.sup.1 OAr.sup.2).sub.m -- or --(OAr.sup.2 OAr.sup.1).sub.m --;
• and
• Y is hydroxy, --(OAr.sup.3 O)--Z.sup.2 --(CH.sub.2 CH.sub.2 O).sub.p --R.sup.1, or --(OAr.sup.4 O)--(CH.sub.2 CH.sub.2 O).sub.p --R.sup.1 ;
• in which Z.sup.1 is selected from --N(R.sup.2)--(SO.sub.2)--C.sub.6 H.sub.4 -- and --N(R.sup.2)--(C.dbd.O)--C.sub.6 H.sub.4 --, R.sup.2 being C.sub.1-12 alkyl or C.sub.6-20 aryl;
• Z.sup.2 is selected from --C.sub.6 H.sub.4 --(SO.sub.2)--N(R.sup.3)-- and --C.sub.6 H.sub.4 --(C.dbd.O)--N(R.sup.3)--, R.sup.3 being C.sub.1-12 alkyl or C.sub.6-20 aryl;
• R.sup.1 is C.sub.1-20 alkyl, C.sub.7-20 alkylaryl, C.sub.7-20 arylalkyl, or C.sub.1-20 perfluoroalkyl;
• each of Ar.sup.1 and Ar.sup.3 is independently selected from 1,4-phenylene, 1,3-phenylene, naphthyl-1,4-diyl, naphthyl-1,5-diyl, 4,4'-biphenylene, diphenyl ether-4,4'-diyl, diphenylthioether-4,4'-diyl, diphenylisopropylidene-4,4'-diyl, diphenylhexafluoroisopropylidene-4,4'-diyl, diphenylalkylene-4,4'-diyl wherein alkylene is --(CH.sub.2).sub.q --, q being 1, 3, 5, 7 or 9, p-terphenyl-4,4'-diyl, and bivalent radicals of binaphthalene, anthracene, and phenylnaphthalene;
• each of Ar.sup.2 and Ar.sup.4 is independently selected from diphenylsulfoxide-4,4'-diyl, diphenylsulfone-4,4'-diyl, diphenyl ketone-4,4'-diyl, and bivalent radicals of diphenyl-C.sub.1-12 alkyl phosphine oxide and diphenyl-C.sub.6-20 aryl phosphine oxide;
• m is between 1 and 250;
• and
• p is between 20 and 500;
• (ii) 0-40 weight percent of polysulfone;
• and
• (iii) 40-95 weight percent of a polar aprotic solvent selected from N-methylpyrrolidinone, 4-butyro-lactone, dimethylsulfoxide, and dimethylformamide;
• contacting said casting solution with a nonsolvent coagulation bath until a porous polymer article forms;
• and
• thermally annealing said article in the presence of water to enhance the hydrophilicity of said article.