PVA/ChCl Deep Eutectic Polymer Blends for Transparent Strain Sensors with Antifreeze, Flexible, and Recyclable Properties

Wearable elastic electronic devices have attracted tremendous attention due to their monitoring capabilities for human motion detection. In this work, a hydrogen bond acceptor quaternary ammonium salt, choline chloride (ChCl), has been used to fabricate deep eutectic polymer (DEP) blends with polyvinyl alcohol (PVA). The miscibility, molecular interaction, and physical properties of PVA/ChCl DEP blends were investigated systematically. It is demonstrated that the deep eutectic of PVA/ChCl can be obtained by simple solution blending, and the melting points of both PVA and ChCl are reduced respectively due to the strong hydrogen bond between PVA and ChCl. Due to the elasticity of the PVA/ChCl elastomer and the response of ChCl ions to temperature and humidity, the fabricated sensor showed stable and repeatable resistance changes upon strain, temperature, and humidity variations. We hypothesize that the DEP blend system has potential applications in functional composites and the final PVA/ChCl elastomer composites exhibited high transparent, antifreeze, and recyclable capability, which may be promising for applications in soft/flexible devices.