Photo masking via breaking alkyl C Se bond of selenium-containing maleimide polymers by ultraviolet light

Abstract

• Obtained polymer with alkyl C Se bond has similar transparency with polystyrene (PS), higher the refractive index than PS and comparable thermostability with PS. • The pattern is directly visual under natural light without any extra treatments and the reaction condition of photo-corsslinking does not require photoacid, photoinitiator and other agents. • The obtained pattern has excellent solution resistance, duo to its cross-linked structure. • The pattern keeps a smooth surface without deformation, which avoides its distortion. To investigate the complexity of breaking aryl C Se bond, alkyl C Se bond and alkyl C S bond by ultraviolet light, three maleimide polymers are employed as objects, including SePhP which reported in our previous work having aryl C Se bond, SePP which synthesized via radical copolymerization of N -(4-selenophenyl)-propyl maleimide and styrene having alkyl C Se bond and SPP which synthesized via radical copolymerization of N -(4-thiophenyl)-propyl maleimide and styrene having alkyl C S bond. After careful structure characteristics, SePhP, SePP and SPP are treated by ultraviolet light, as a result, only C Se bond of SePP can be broken. When SePP is irradiated by ultraviolet light in an oxygen-free condition, it can make a structure change from linear to cross-linked and refractive index decrease of polymer. Furthermore, utilizing photo-crosslinking and changing of refractive index of SePP after ultraviolet light irradiation, we realize visual photomask patterning in a simple system, which will bring great potential in display devices, anti-counterfeit labels, and etc.