Preparation of Polyvinyl alcohol Hydrogel Braided Wire Reinforced by Soluble starch Granules Based on Magnetoionic induction and Piezoelectric sensing

Abstract Integrating textiles with a signal collector may provide sustainable solutions for wearable electronic devices in the Internet of Things era owing to the soaring development of chemistry and materials. This study adopted soluble starch(S) granules for advancing the resistance and formability of polyvinylalcohol (PVA) hydrogel in the structural deformation stage, thus preparing a PVA based composite hydrogel wire that may be produced continuously. In the whole process, the mechanical performance, strain resistance and sensing property of the hydrogel wire were studied. The results showed that when PVA : S=7 : 3, the hydrogel wire had the best formability and mechanical performance, and the stress and strain were 2.3 MPa and 255 % respectively. When starch granules were added in the hydrogel wire, the coincidence degree between starting stress and cyclic stress was increased after the wire was stretched by 17.5 %, and thus, the stability of the hydrogel wire was improved. In addition, the electronic skin strain sensors assembled with hydrogel wires can detect the movement of different parts of the body effectively. In particular, a piezoelectric sensor braided with polyurethane‐encapsulated hydrogel wire may not only generate a voltage about 0.4 mV at a slight touch, but also locate the stress point. When an induction coil is prepared with the hydrogel wire, the magnetoionic induction of a single coil can produce a significant induced voltage, which is conductive to the wireless signal transmission of hydrogel. As a conductor, the hydrogel wire also had a current reaction in phase to AC voltage. And according to the experiment, it is speculated that as braided and electronically integrated, the hydrogel wire can be used in smart fabrics for strain sensing, wireless signal transmission, and force location.