A Nature-Inspired, Flexible Substrate Strategy for Future Wearable Electronics

Research output: Contribution to journalArticle

DOI

Authors

  • Chuang Zhu
  • Evelyn Chalmers
  • Liming Chen
  • Yuqi Wang
  • Ben Bin Xu
  • Yi Li
  • Xuqing Liu

External departments

  • University of Manchester

Details

Original languageEnglish
Article number1902440
JournalSmall
Volume15
Issue number35
Early online date19 Jun 2019
DOIs
Publication statusPublished - 28 Aug 2019
Publication type

Research output: Contribution to journalArticle

Abstract

Flexibility plays a vital role in wearable electronics. Repeated bending often leads to the dramatic decrease of conductivity because of the numerous microcracks formed in the metal coating layer, which is undesirable for flexible conductors. Herein, conductive textile‐based tactile sensors and metal‐coated polyurethane sponge‐based bending sensors with superior flexibility for monitoring human touch and arm motions are proposed, respectively. Tannic acid, a traditional mordant, is introduced to attach to various flexible substrates, providing a perfect platform for catalyst absorbing and subsequent electroless deposition (ELD). By understanding the nucleation, growth, and structure of electroless metal deposits, the surface morphology of metal nanoparticles can be controlled in nanoscale with simple variation of the plating time. When the electroless plating time is 20 min, the normalized resistance (R/R0) of as‐made conductive fibers is only 1.6, which is much lower than a 60 min ELD sample at the same conditions (R/R0 ≈ 5). This is because a large number of unfilled gaps between nanoparticles prevent metal films from cracking under bending. Importantly, the Kelvin problem is relevant to deposited conductive coatings because metallic cells have a honeycomb‐like structure, which is a rationale to explain the relationships of conductivity and flexibility.