A stretchable and adhesive composite hydrogel containing PEDOT:PSS for wide-range and precise motion sensing and electromagnetic interference shielding and as a triboelectric nanogenerator

Abstract

Flexible conductive hydrogels with excellent mechanical properties and stable electrical conductivity are ideal candidates for bioelectronic devices. However, the development of modern electronic products has higher requirements in terms of functionality of the materials. Herein, a composite hydrogel composed of polyvinyl alcohol (PVA), polyacrylic acid (PAA) and the conductive polymer PEDOT:PSS was developed, and the addition of tannic acid (TA) made the hydrogel possess good adhesion. The hydrogel exhibits excellent flexibility (640%, 123.1 kJ m⁻³) and electrical conductivity and can be adhered to various substrates with an adhesion strength of 14.97 kPa. In addition, benefiting from its excellent electrical conductivity and high-water content, the PVA/PAA-PEDOT:PSS-TA conductive hydrogel has an excellent EMI shielding effect. The PVA/PAA-PEDOT:PSS-TA hydrogel sensor can not only successfully detect various signals from human motion, but also express sign language through electrical signals when it was attached to five fingers, which provides a new idea for its application as a flexible wearable device for the deaf or hard-of-hearing people who do not speak verbally and under special situations. Importantly, this hydrogel can also act as a flexible triboelectric nanogenerator (TENG) with an adjustable output voltage for energy harvesting. This work was expected to provide avenues for the development of new intelligent systems for health monitoring and energy harvesting.