Photo-responsive microencapsulation materials, compositions and methods of use thereof

A method for producing microcapsules comprising a substantially water-insoluble liquid material within a non-porous, light-sensitive shell, wherein the non-porous shell is characterized by a release rate of the liquid material in the absence of light of less than 1 ppm/minute, wherein exposure to light converts the nonporous shell into a porous shell characterized by a release rate of the liquid material of from 1 to at least 100 ppm/minute, the method comprising the steps of:

• (a) providing an organic solution comprising said liquid material and a photoactivatable prepolymer or mixture of a photoactivatable prepolymer and a nonphotoactive-based prepolymers dissolved therein, wherein the photoactivatable prepolvmer is selected from the group consisting of (+/−)3-[1-(2-aminoethoxy)-2-oxo-2-phenylethyl] phenoxy acetic acid, 2-(2-hydroxyethoxy)-2-[3-(2-hydroxyethoxy)-5-methylphenyl]-1-phenylethanone, and photoactivatable combinations thereof;
• (b) creating an emulsion of said organic solution in a continuous phase aqueous solution comprising water and a surface-active agent, wherein said emulsion comprises discrete droplets of said organic solution dispersed in said continuous phase aqueous solution, there being formed thereby an interface between the discrete droplets of organic solution and the surrounding continuous phase aqueous solution;
• and
• (c) causing in situ self-condensation and curing of said prepolymers in the organic phase of said discrete droplets adjacent to said interface by catalysis using heat, pH, or a chemical or free radical initiator for a time sufficient to allow substantial completion of in situ condensation of said prepolymers, thereby converting the liquid droplets of said organic solution to microcapsules comprising a solid nonpermeable polymer shell that encloses said liquid material.