Highly sensitive and flexible micro-patterned PPy/PDMS strain sensors with enhanced conductivity and stretchability for wearable electronics

• Published in: Polymer (Guilford) 2024-08, Vol.308, p.127356, Article 127356
• Main Authors: Muhammad, Waqar, Kim, Sam-Dong
• Format: Article
• Language: English
• ISSN: 0032-3861
• DOI: 10.1016/j.polymer.2024.127356

This study presents a pioneering approach to enhance the performance of flexible strain sensors based on polypyrrole (PPy) by incorporating micro-patterns onto polydimethylsiloxane (PDMS) substrates. Micro-patterned PPy films were generated through image-reversal photolithography and pattern lift-off followed by a straightforward chemical oxidative polymerization process to deposit the films. A method of surface treatment using the dopant sodium dodecylbenzenesulfonate (SDBS) was also used to enhance the conductivity of the degraded PPy films after the formation of patterns. We conducted a systematic exploration of various fabrication conditions, including unpatterned and three micro-patterned variants. Utilizing X-ray photoelectron spectroscopy analyses, we investigated the interplay between SDBS treatment, structural modifications, and strain sensor performance. Our results unveiled that micro-patterned sensors treated with SDBS and capped by PDMS layer showed remarkable performance attributes. The sensors fabricated by this method exhibited a gauge factor of 35 at 100 % strain, coupled with a very fast response time of ∼2.8 ms under quasi-step function strain ranging from 0 to 1 % in 1.8 ms, demonstrating excellent durability across 500 stretching/release cycles. This study provides invaluable insights into enhancing the effectiveness of micro-patterned PPy/PDMS strain sensors, opening avenues for their widespread utilization in wearable electronics. [Display omitted] •Highly flexible strain sensors were fabricated using micro-patterned polypyrrole films on PDMS substrates.•The SDBS-treated, micro-patterned PPy/PDMS sensor capped with PDMS displayed superior sensing performance.•A gauge factor of ∼35 was achieved in the 0–100% strain range.•An ultra-fast transient response time of ∼2.8 ms was recorded under 0–1% strain.•Analyses of surface morphologies, XPS, and electrical characteristics examined the impact of micro-patterns and SDBS dopant on strain sensor performance.