Biocompatible and highly stretchable PVA/AgNWs hydrogel strain sensors for human motion detection

Shohreh Azadi, Shuhua Peng, Sajad A. Moshizi, Mohsen Asadnia, Jiangtao Xu, Inkyu Park, Chun H. Wang, Shuying Wu*

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

Hydrogel-based strain sensors have attracted considerable interest for applications such as skin-like electronics for human motion detection, soft robotics, and human–machine interfaces. However, fabrication of hydrogel strain sensors with desirable mechanical and piezoresistive properties is still challenging. Herein, a biocompatible hydrogel sensor is presented, which is made of polyvinyl alcohol (PVA) nanocomposite with high stretchability up to 500% strain, high mechanical strength of 900 kPa, and electrical conductivity (1.85 S m-1) comparable to human skin. The hydrogel sensors demonstrate excellent linearity in the whole detection range and great durability under cyclic loading with low hysteresis of 7%. These excellent properties are believed to be contributed by a new bilayer structural design, i.e., a thin, conductive hybrid layer of PVA/silver nanowires (AgNWs) deposited on a pure strong PVA substrate. PVA solution of high concentration is used to fabricate the substrate while the top layer consists of dilute PVA solution so that high content of AgNWs can be dispersed to achieve high electrical conductivity. Together with a rapid response time (0.32 s) and biocompatibility, this new sensor offers great potential as a wearable sensor for epidermal sensing applications, e.g., detecting human joint and muscle movements.

Original languageEnglish
Article number2000426
Pages (from-to)1-12
Number of pages12
JournalAdvanced Materials Technologies
Volume5
Issue number11
Early online date6 Sep 2020
DOIs
Publication statusPublished - Nov 2020

Keywords

  • biocompatibility
  • human motion detection
  • hydrogel strain sensors
  • polyvinyl alcohol

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