Temperature effects on pinpoint photopolymerization and polymerized micronanostructures

Abstract

The spatial resolution in pinpoint two-photon photopolymerization of radical-type resins was found to be improved by varying the liquid sample temperature from a critical value Tc. For SCR-500 and NOA-61, the currently widely used resins, Tc is around room temperature. The improvement of spatial resolution by temperature decrease was attributable to restraint radicals diffusion; while the voxel size reduction versus temperature increase was considered as arising from enhanced chain termination. Furthermore, temperature plays an important role in size tuning of polymerized structures, for example, a photonic crystal blueshifted its working wavelength for 50 and 400nm when heated at 200 and 300°C, respectively, indicating the possibility to precisely tailor the photonic bandgap by means of thermal processing.