Engineering robust and transparent dual-crosslinked hydrogels for multimodal sensing without conductive additives

Conductive hydrogels are pivotal for the advancement of flexible sensors, electronic skin, and healthcare monitoring systems , facilitating transformative innovations. However, issues such as inadequate intrinsic compatibility, mismatched mechanical properties, and limited stability curtail their potential, resulting in compromised device efficacy and performance degradation . In this research, we engineered functional hydrogels featuring a dual-crosslinked network composed of (PA/PVA)-P(AM-AA) to address these challenges. This design eliminates the need for conductive additives, thereby enhancing intrinsic compatibility. Notably, the hydrogels exhibit exceptional mechanical properties, with high tensile strength (∼700 %), Young's modulus (∼5.33 MPa), increased strength (∼2.46 MPa) and toughness (∼6.59 MJ m −3 ). They also achieve a compressive strength of ∼7.33 MPa at 80 % maximal compressive strain and maintain about 89 % transparency. Moreover, flexible sensors derived from these hydrogels demonstrate enhanced multimodal sensing capabilities, including temperature, strain, and pressure detection, enabling precise monitoring of human movements. The integration of multiple hydrogels into a three-dimensional sensor array facilitates detailed spatial pressure distribution mapping. By strategically applying dual-crosslinked network engineering and eliminating conductive additives, we have streamlined the design and manufacturing of hydrogels to meet the rising demand for high-performance wearable sensors .