Emulsion polymerization of methacrylonitrile as vehicle for vesicular photography and method of making and using same

A light sensitive vesicular material comprising a film support and a coating therefor forming a vesicular matrix wherein regulated inner incompatibility supplies domains of incompatibility which serve as nucleation centers, the continuous phase of said coating comprising:

• (a) a copolymer of a first monomer of methacrylonitrile and a second monomer of vinyl acetate, prepared by emulsion polymerization using an anionic or non-ionic emulsifier, wherein a homopolymer of said second monomer would be incompatible with a polymer of said first monomer, said copolymer comprising a nucleation enhancing amount which is less than 5% by weight of said second monomer with the remainder of the copolymer being said first monomer which produces a homopolymer of low nitrogen permeability, or
• (b) a blend of a first polymer or copolymer of methacrylonitrile with a nucleation enhancing amount which is less than 5% by weight of a second polymer or copolymer of vinyl acetate or a vinyl chloride/vinyl acetate copolymer, said first and second polymers or copolymers being incompatible with each other and said first polymer or copolymer having a low nitrogen permeability;
• and an effective gas-generating amount of a photo-sensitive solid agent substantially uniformly dispersed within said coating, which agent is capable of decomposing to produce nitrogen gas upon exposure to light.