Polyion complex and polyion complex film

A polyion complex produced by reacting a polyanion polymer selected from the group consisting of polystyrenesulfonic acid, polyvinylsulfonic acid, polyacrylic acid, polymethacrylic acid, carboxymethyl cellulose, alginic acid or an alkali salt thereof with a polycation polymer having a terminal ethylenic double bond in the repeating units of the polymer and having repeating units of the formula:

• ##STR13## wherein R.sub.1 represents hydrogen, or a C.sub.1-4 alkyl group;
• R.sub.2 represents a group having the formula:
• --CH.sub.2 - C(R) = CH.sub.2,
• --ch.sub.2).sub.m COOC (R) = CH.sub.2,
• --ch.sub.2).sub.m COOCH.sub.2 - C (R) = CH.sub.2,
• --ch.sub.2).sub.m O - C(R) = CH.sub.2,
• --ch.sub.2).sub.m O - CH.sub.2 - C(R) = CH.sub.2, or ##STR14## wherein R is hydrogen or a C.sub.1-4 alkyl group, m is 1 to 3 and n is 0 or 1;
• R.sub.3, R.sub.4 and R.sub.5 represents a C.sub.1-4 alkyl group or an alkylol group and at least one of R.sub.3, R.sub.4 and R.sub.5 is the group of R.sub.2 or a group having the formula:
• --CH.sub.2).sub.m CONH - C(R) - CH.sub.2, wherein
• R is hydrogen or a C.sub.1-4 alkyl group and m is 1 or 2;
• n is 0 or an integer less than 40,000;
• x is an integer of 10 to 50,000;
• M represents a vinyl monomer having an ethylenic double bond selected from the group consisting of styrene, .alpha.-methylstyrene, acrylonitrile, methacrylonitrile, and butadiene;
• and X represents a halogen atom or a hydroxyl group.