Thiol‐ene polymerization of double‐decker‐shaped phenyl‐substituted silsesquioxanes and thiol monomers

Polymers incorporating double‐decker‐shaped phenyl‐substituted silsesquioxane (DDSQ) into the main chain are expected to exhibit excellent thermal stability and significantly reduced dynamics of the polymer segments. In this study, thiol‐ene polymerization at 25 °C for 5 min under 365 nm irradiation was applied for 3,13‐divinyl‐DDSQ ( E1 ) with oxybis(2,1‐ethanediyloxy‐2,1‐ethanediyl) bis(3‐sulfanylpropanoate) ( T1 ) as a bithiol monomer for linear and 2,2‐bis{[(3‐sulfanylpropanoyl)oxy]methyl}butyl 3‐sulfanylpropanoate ( T2 ) as a trithiol monomer for soluble cross‐linked poly(thioether)s. All the resulting poly(thioether)s yielded colorless and transparent films by casting tetrahydrofuran solutions onto glass substrates. These polymers showed a higher decomposition temperature of 5 wt% loss over 350 °C. The films exhibited glass transition temperatures below 25 °C. Scratch scars were made on the surface of the cast films, and the self‐healing behavior was observed after heating at 40 °C. These results suggest that the DDSQ unit suppresses the molecular motion of the polymers and contributes to their self‐healing behavior.