Emotion-interactive empathetic transparent skin cushion with tailored frequency-dependent hydrogel-plasticized nonionic polyvinyl chloride interconnections

Using a smart polymeric material, we design a transparent and stretchable empathetic haptic skin cushion that secretly allows a target device to understand users' emotions. The skin comprises highly transparent and stretchable conducting hydrogels and a plasticized nonionic polyvinyl chloride (PNIPVC) whose dielectric, electrical, optical, and mechanical properties are adjusted by the type, ratio, and concentration of the dual plasticizers. Hydrogels adhere strongly to the upper and lower surfaces of the PNIPVC via covalent bonding to form durable, reliable, and sensitive empathetic skin. The skin exhibits excellent transparency and stretchability with low mechanical hysteresis. In addition, the skin senses the capacitance or resistance of the PNIPVC by varying its operating frequency, which enables the perception of various external pressures for detecting emotional touches (tapping, patting, stretching, pinching, and twisting). Thus, the skisn cushion can be used as a new tactile emotional interface system for future emotion-interactive shape-deformable materials and devices.