Trace Material Capture by Controlled Liquid Droplets\non a Superhydrophobic/Hydrophilic Surface

Abstract

A liquid\ndroplet in contact with a superhydrophobic surface can\nbe used to collect dissolved trace materials after evaporating the\nsolvent. This process effect enhances detection limits, but a liquid\ndroplet easily rolls off a superhydrophobic surface. Keeping it at\na specific collecting spot area is challenging. Here the means for\ncontrolling and capturing a liquid droplet on a superhydrophobic surface\nis demonstrated. To induce a liquid droplet to a collecting spot,\nits rolling direction was controlled by two superhydrophobic fabric\nguides. The liquid droplet was then captured by hydrophilic polymer\nand hydrophilic nanoparticles at the measuring spot. After removing\nthe solvent, the trace compounds were evaluated with a colorimetric\nanalysis visible to the naked eye.