A Skin-like Hydrogel with Multidimensional Fillers for Stable Human-Machine Interaction

The deep integration of human-machine interface (HMI) technology and the Internet of Things (IoT) has imposed stringent new requirements for electronic skin (e-skin) in terms of flexibility, comfort, and high sensitivity. Herein we present a multiconductive network hydrogel e-skin (MCNHE-skin) based on a poly(vinyl alcohol) (PVA)/polyvinylpyrrolidone (PVP) dual-network matrix with polydopamine (PDA), carbon nanotubes (CNTs), and MXene as conductive fillers. The MCNHE-skin exhibits electrical conductivity (<5 kΩ), high stretchability (∼650%), strong self-adhesion (∼19 kPa), and low modulus (∼3.6 kPa). These characteristics enable its successful application in multimodal sensing systems such as strain sensors, pressure sensors, triboelectric nanogenerators (TENGs), and physiological signal monitors. Furthermore, by integration with flexible printed circuit boards (FPCBs), MCNHE-skin is developed into smart wearable systems for noncontact HMI. The 0D/1D/2D synergistic conductive network presented in this hydrogel e-skin yields high-fidelity sensing and noncontact control capabilities, marking a significant step forward in the development of multifunctional wearable electronics.