Interfacial Engineering of Transparent Elastomer with Thickotropic Parylene Films Toward Stretchable Electronics

ABSTRACT As the display industry advances toward form‐free factors, the development of polymeric insulators and substrate materials for stretchable device applications has lagged behind progress in semiconductors and metals. In particular, research focusing on the stretching properties of the cover window (outermost layer) and substrate has often overlooked crucial aspects, limiting the overall utilization of the final device. In this study, parylene polymer prepared via chemical vapor deposition is proposed as a reinforcement layer for the surfaces of stretchable elastomers. Parylene, a well‐known aromatic polymer with excellent mechanical properties, can paradoxically exhibit elastic behavior in an ultrathin film, making it suitable for interfacial application with stretchable materials. When integrated with elastomers as a reinforcing layer, parylene effectively addresses their intrinsic limitations; removing nearly all tackiness (<0.2 gf), imparting high surface hardness, and enhancing various recovery performances (92.13% of strain recovery rate) with maintaining their optical properties before/after stretching (>97.2% of visible transmittance). Through a remarkably easy‐to‐craft yet innovative approach, this study has significant theoretical and industrial implications for the development of novel stretchable elastomers, accelerating the commercialization of future display technologies.