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Biocompatible and Highly Stretchable PVA/AgNWs Hydrogel Strain Sensors for Human Motion Detection
Author(s) -
Azadi Shohreh,
Peng Shuhua,
Moshizi Sajad A.,
Asadnia Mohsen,
Xu Jiangtao,
Park Inkyu,
Wang Chun H.,
Wu Shuying
Publication year - 2020
Publication title -
advanced materials technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.184
H-Index - 42
ISSN - 2365-709X
DOI - 10.1002/admt.202000426
Subject(s) - materials science , piezoresistive effect , biocompatibility , nanotechnology , electronic skin , substrate (aquarium) , artificial muscle , soft robotics , layer (electronics) , nanocomposite , gauge factor , bioelectronics , biocompatible material , polyvinyl alcohol , flexible electronics , composite material , fabrication , biosensor , biomedical engineering , actuator , computer science , medicine , artificial intelligence , oceanography , alternative medicine , pathology , geology , metallurgy
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.