Degradable Cross-Linkers and Strippable Imaging Materials for Step-and-Flash Imprint Lithography

Abstract

The ability to produce tough, cross-linked networks that can, if necessary, be rendered soluble by an external stimulus such as acid or heat is highly desirable for a number of applications. An acetal containing diacrylate, 2,2-di(acryloyloxy-1-ethoxy)propane (ADA) (1), was synthesized by transketalization with 2-hydroxyethyl acrylate. Its photopolymerization kinetics were measured by real-time FT-IR and its degradation in acidic organic solvents was evaluated. Additionally, a diacrylate cross-linker containing a thermally labile Diels−Alder (DA) linkage (2) was synthesized and its reversibility was evaluated using solid-state NMR spectroscopy. The DA cross-linker (2) and ADA (1) were evaluated for use in Step-and-Flash Imprint Lithography (S-FIL). Finally, a dimethacrylate cross-linker containing a thermally labile urethane-oxime linkage (10) was synthesized. Its copolymerization with methyl methacrylate and reversibility were evaluated by size exclusion chromatography (SEC) and 1H NMR spectroscopy.