Microchannel–engraved and Cu–dispersed carbon nanocomposite film as a chemiresistive sensor for aqueous metal ions

Abstract

A Cu-carbon nanocomposite film (2 mm thickness) is fabricated as an efficient chemiresistive sensor for aqueous Cd. The novelty of the study is in fabrication of the laser-ablated vertical microchannels (200 µm wide × 100 µm deep × 200 µm inter-spacing) on both sides of the carbon film. The microchannels speed up sensing by inducing a reproducible capillary action in the film, with a rapid rise of the liquid and wetting of the material, and augmenting exposure of the electroconductive Cu nanoparticles to the analyte through the porous textured walls. Capillary action and wetting are facilitated by hydrophilic functional groups in the material. Notably, the sensor response (electrical resistance of the film) is approximately linear (R2 = 0.977) over the concentration range 10 – 150 ppb. The microfluidics-based approach used in this study can be easily extended to develop fast chemiresistive sensors for biofluids, and the other metals in wastewater.