SUMMARY
The proposed research is aimed at exploring the thermo-mechanical properties of thiol-ene polymers in bulk form, investigating the ability of thiol-ene polymers to behave desirably as photolithographic media, and providing the first characterization of the mechanical properties of two-photon stereolithography-produced polymers. The thiol-ene polymerization reaction itself is well-characterized, but the thermo-mechanical properties of thiol-ene and thiol-ene/acrylate polymers still require much more rigorous study. Understanding the behavior of thiol-ene networks is a crucial step towards their expanded use in bulk form, and particularly in specialized applications such as shape memory devices. The thiol-ene polymerization reaction mechanism exhibits unique properties which may make these polymers extremely well suited to photolithography, overcoming the typical dichotomy of current materials which either exhibit excellent photolithographic behavior or have controllable properties. Finally, before two-photon stereolithography can create mechanisms and devices which can serve any mechanically functional role, the mechanical properties of the polymers they produce must be quantitatively characterized, which is complicated by the extremely small scale at which these structures are produced. The broad objective of the proposed research is to explore thiol-ene polymer behavior both in bulk and at the small scale in an effort to supplement the material library currently used in these fields and to expand the design envelope available to researchers. The significance of the research is the advancement of a more complete and fundamental understanding of thiol-ene polymerization from kinetics to final properties, the quantitative establishment of the mechanical properties of materials created with two-photon stereolithography, and the characterization of a supplementary class of photopolymers with greater property tunability than is possible with current materials.