Highly sensitive, stretchable and durable strain sensors based on conductive double-network polymer hydrogels

Kaiqi Pan, Shuhua Peng, Yingying Chu, Kang Liang, Chun H. Wang, Shuying Wu, Jiangtao Xu*

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

Hydrogel-based strain sensors have been attracting immense attention for wearable electronic devices owing to their intrinsic soft characteristics and flexibility. However, developing hydrogel sensors with hightensile strength, stretchability, and strain sensitivity remains a great challenge. Herein, we report a technique to synthesize highly sensitive hydrogel-based strain sensors by integrating carbon nanofibers (CNFs) with a double-network (DN) polymer hydrogel matrix comprising of a physically cross-linked agar network and a covalently cross-linked polyacrylamide (PAAm) network. The resultant nanocomposite sensors display superior piezoresistive sensitivity with a hightrue gauge factor (GFT = 1.78) at an ultrahigh strain of 1,000%, a fast response time and linear correlation of ln(R/R0) and ln(L/L0) up to 1,000% strain. Most significantly, these sensors possess highmechanical strength (~0.6 MPa) and superb durability (>1,000 cycles at strain of 100%), stemming from the effective energy dissipation mechanism of the first agar network acting as sacrificial bonds and the CNFs serving as dynamic nanofillers. The combination of highstrain sensitivity and ultrahigh stretchability of hydrogel sensors makes it possible to sense both small mechanical deformations induced by human motions and large strain up to 1,000%.

Original languageEnglish
Pages (from-to)3069-3081
Number of pages13
JournalJournal of Polymer Science
Volume58
Issue number21
DOIs
Publication statusPublished - 1 Nov 2020

Keywords

  • double-network hydrogel
  • gauge factor
  • highly stretchable
  • human motion detection
  • strain sensor

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