Temperature effects on pinpoint photopolymerization and polymerized micronanostructures

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.