Photothermal composites for in-situ trace oil detection on ultra-clean surfaces

Oil is widely used as a lubricant in many industries. However, in the final product, oil is often considered a contaminant. In various production processes, such as semiconductor manufacturing, precision machining, and optical device fabrication, ultra-clean surfaces are crucial. Oil residues on these surfaces can adversely affect product performance and quality. Detecting and controlling oil residues enables enhancing product reliability and consistency. Previous lipid detection studies necessitate complex pre-processing, large instruments, or specialized manipulation and data reading capabilities. Existing methods for trace oil detection still cannot achieve on-site real-time monitoring. This study presents a photothermal conversion-based platform for trace oil adsorption and detection. Using polyester fiber membranes as the substrate, a composite material of chitosan and MXene was modified to remove trace oil on ultra-clean surfaces. Due to their inherent thermal conductivity and ability to trap heat inside, the oil molecules intensify the material's temperature rise under near-infrared excitation at 808 nm. By connecting a thermal imaging module to a smartphone, real-time detection of trace oil can be achieved.