Selective microthermal actuation enabled by complex patterning of laser-induced graphene

Abstract

Laser-induced graphene (LIG) patterned in a single-pass CO2-laser step enables addressable microheaters on flexible polyimide films. By tuning linewidth, gap, and electrode layout, discrete LIG elements can be activated individually or along predefined paths, delivering millimeter-scale, site-specific heating without mechanical reconfiguration. A 4 × 4 matrix heater offers programmable thermal pixels: switching two bias lines directs current, and consequently heat, along the shortest-resistance path, producing local temperatures from 25 to 150 °C. Representative tracks reach 165 °C at 5 V, while a 2 V bias yields an increase in ≥ 40 °C. Because the temperature field is primarily governed by the geometry of the conductive tracks, not the overall heater size, the same fabrication step can yield regions with different thermal outputs by adjusting local pattern dimensions such as linewidth and length. This ability to spatially program heating behavior within a thin, flexible film, where heat distribution can be reconfigured simply by changing the biasing direction, highlights its potential for applications in reconfigurable soft robotics, on-skin thermal therapy, and adaptive microfluidic control.