Highly Stretchable and Sensitive Unidirectional Strain Sensor via Laser Carbonization

TLDR

The paper introduces a simple, low‑cost method to fabricate highly stretchable (up to 100 % strain) and highly sensitive (gauge factor up to 20 000) strain sensors. The method uses selective laser pyrolysis of thermoset polymers to create carbonized patterns, which are then transferred and embedded into elastomeric substrates, producing partially aligned graphene and CNT structures that provide directional anisotropy for robust, highly stretchable, unidirectional sensors. Raman analysis confirms that optimal laser settings yield highly porous carbon nano/microparticles with sheet resistances as low as 60 Ω/□, and the technique enabled the fabrication of an instrumented latex glove capable of real‑time finger‑motion measurement.

Abstract

In this paper, we present a simple and low-cost technique for fabricating highly stretchable (up to 100% strain) and sensitive (gauge factor of up to 20 000) strain sensors. Our technique is based on transfer and embedment of carbonized patterns created through selective laser pyrolization of thermoset polymers, such as polyimide, into elastomeric substrates (e.g., PDMS or Ecoflex). Embedded carbonized materials are composed of partially aligned graphene and carbon nanotube (CNT) particles and show a sharp directional anisotropy, which enables the fabrication of extremely robust, highly stretchable, and unidirectional strain sensors. Raman spectrum of pyrolized carbon regions reveal that under optimal laser settings, one can obtain highly porous carbon nano/microparticles with sheet resistances as low as 60 Ω/□. Using this technique, we fabricate an instrumented latex glove capable of measuring finger motion in real-time.