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

Author：Zheng, Y. P., Cui, T. Y., Wang, J. W., Hu, Y., Gui, Z.

Journal：Journal of Colloid and Interface Science

DOI:  10.1016/j.jcis.2024.06.192http://10.1016/j.jcis.2024.06.192

Keywords: Hydrogel, Dual-crosslinked network, Multimodal sensing, 3D sensor array, Chemistry

Abstract: 

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.