Solvent‐Resistant Natural Rubber With Humidity‐Responsive Functionality Enabled by Layer‐by‐Layer Self‐Assembly for Sensor Applications

ABSTRACT

We develop a general strategy for preparing solvent‐resistant coated natural rubber by constructing a chemically stable polymer layer on the surface of natural rubber via layer‐by‐layer self‐assembly. The coating process entails the sequential layer‐by‐layer deposition of poly(diallyldimethylammonium) chloride ( PDDA ) and poly(styrenesulfonate) ( PSS ) onto the rubber surface, which is subsequently immersed in aqueous solutions of polyvinyl alcohol ( PVA ). The resulting coating effectively protects natural rubber from organic solvent erosion and dissolution, enabling the coated rubber to remain intact in toluene for over 15 h and in common oils for more than 7 days, without compromising its mechanical properties. By using this solvent‐resistant coating, and integrating the humidity‐sensitive property of PVA with the excellent mechanical performance of natural rubber, we uniformly deposit the PVA layer in the form of microdroplets onto one side of the curved surface of natural rubber. We fabricate a natural rubber material with humidity‐responsive capability and extend its potential applications in the field of humidity sensors.