Thermal and UV light adaptive polyurethane elastomers for photolithography-transfer printing of flexible circuits

Mater Horiz. 2022 Nov 28;9(12):3070-3077. doi: 10.1039/d2mh01005d.

Abstract

Flexible polymers are widely used in the fields of wearable devices, soft robots, sensors, and other flexible electronics. Combining high strength and elasticity, electrical conductivity, self-healability, and surface tunable properties in one material becomes a challenge for designing polymeric materials for these applications, especially in flexible electronics. Herein, we propose a "two birds with one stone" strategy to synthesize thermal and UV light adaptive polyurethane elastomers with high-strength, self-healable, surface-modifiable and patternable functions for photolithography-transfer printing flexible circuits. The "stone", dihydroxybenzophenone, plays two roles in the synthesized polyurethanes as both a dynamic covalent bond and a UV-sensitive unit. On one hand, the phenolic group reacts with isocyanate to form a dynamic covalent phenol-carbamate bond, making the polymer self-healable, processable, and surface-embeddable with conductive fillers utilizing dynamic network rearrangement. On the other hand, the benzophenone group acts as a UV-sensitive unit to graft other functional groups to the polymer surface or self-crosslink on the surface under UV irradiation. Based on the dynamic covalent network and UV self-crosslinking properties, self-healable patterned flexible circuits can be obtained by photolithography-transfer printing. The flexible circuits prepared by loading silver nanowires on the dynamically crosslinked polyurethane substrate show little change of electric resistance when stretched up to 125% and can withstand thousands of stretching cycles.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Elastomers* / chemistry
  • Nanowires
  • Polymers / chemistry
  • Polyurethanes / chemistry
  • Printing*
  • Silver
  • Ultraviolet Rays

Substances

  • Elastomers
  • Polymers
  • Polyurethanes
  • Silver