Mechanically robust and moisture sensitive eutectic elastomers

Abstract

Poly (acrylic acid) - choline chloride (PAA-ChCl) eutectic elastomers possess excellent ionic conductivity, humidity sensitivity, elasticity, self-adhesion, freeze resistance, non-volatility, lack of ion leakage, and cost-effectiveness, making them promising alternatives to hydrogels or ionogels for broader applications. However, the disruption of intermolecular hydrogen bonds by choline chloride and the disappearance of hydrogen bond microdomains lead to poor strength of PAA-ChCl elastomers, which limit their application reliability. Here we report the use of highly entangled double-network strategy to enhance the tensile strength and fracture energy of PAA-ChCl elastomers by an order of magnitude without sacrificing elasticity, and the nominal stress, fracture energy and recoverability are 2.2 MPa, 11.5 kJ m⁻² and 88 %, respectively. The entangled microdomains remain isotropic during stretching, indicating the disappearance of intermolecular interactions − hydrogen bonds, which makes the elastomer have good elasticity. And the significant orientation of lower-order structural polymer chains lead to an increase in tensile strength. Additionally, multifunctional applications related to moisture management have been developed based on the humidity sensitivity of PAA-ChCl elastomers, including antifogging, humidity regulation, and water vapor permeability. This study enhances the practical application reliability of PAA-ChCl elastomers and expands their applications in the field of moisture management.