Development of piezoresistive poly(ɛ-caprolactone) sensor with unique flexibility and sensing performance for rehabilitative application

ABSTRACT

Piezoresistive sensor is applied extensively in rehabilitative monitoring, to help with patients’ physical and mental health recovery. However, the manufacturing complexity of hierarchical structure in sensing element remains a major limitation to piezoresistive sensor. Here, we report a scalable and simple method for the preparation of piezoresistive sensing element. Based on biocompatible poly(ɛ-caprolactone) (PCL), uniaxial cold stretching resulted in a flexible sheet-like element with unique hierarchical geometries comprising highly aligned multiscale ridges on sheet’s double sides. This leads to higher mechanical elasticity of the hierarchitectured PCL element and enhanced resistance against plastic deformation due to the improved Young’s modulus. Further assembly of the piezoresistive sensor demonstrates a wide detection range of 25–4.7 × 10⁴ Pa with rapid response and the high sensitivity of 1.37 kPa⁻¹ at small pressure loadings. The sensor shows successful application in the monitoring physiological signals including pulse, speaking, face expression and limb motion.

GRAPHICAL ABSTRACT

KEYWORDS:

• Flexible electronics
• piezoresistive sensor
• PCL

Disclosure statement

A patent for the preparation technique described in this article has been granted (CN202111248089.X).

Author contributions

Jiabin Liu: Methodology, Visualization, Software, Validation, Investigation, Formal analysis, Writing – original draft, review and editing. Fang Zhong: Methodology, Visualization, Investigation, Formal analysis, Writing – original draft. Peng Liu: Methodology, Discussion. Pan Xu: Methodology, Investigation. Xiaoxi Long: Methodology, Visualization, Discussion. Chao Ma: Resources, Supervision, Funding acquisition, Discussion. Song Liu: Conceptualization, Methodology, Discussion. Nan Lin: Methodology, Discussion. Zuyong Wang: Conceptualization, Resources, Supervision, Project administration, Funding acquisition, Discussion, Writing – review and editing.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/10667857.2024.2332040.

Additional information

Funding

This research was supported by the Outstanding Youth Scientist Foundation of Hunan Province [2020JJ2001], Hunan Provincial Technology Innovation Platform and Talent Program [2017XK2047], and Fundamental Research Funds for the Central Universities of P R China [531107050927]. Dr Z Wang received financial support from Hunan University for the Yuelu Young Scholars [JY-Q/008/2016].