Coating For Cotton Repels Oil And Water

Cotton clothes marred with wet patches and stubborn oily stains could soon be a thing of the past, thanks to a coating that makes oily and aqueous liquids bead up and roll away rather than penetrate the fabric (Langmuir, DOI: 10.1021/la300634v). The superamphiphobic cotton was developed by Guojun Liu and Dean Xiong of Queen’s University, in Ontario, along with E. J. Scott Duncan of Defence R&D Canada, in Alberta. It’s made of a diblock copolymer, PIPSMA-b-PFOEMA, which is short for poly[3-(triisopropyloxysilyl)propyl methacrylate]-block-poly[2-(perfluorooctyl)ethyl methacrylate]. The PIPSMA portion condenses with the hydroxyl groups on the cotton surface, covalently grafting and cross-linking the polymer around the cotton fibers. The fluorinated PFOEMA part of the polymer gives the cotton fibers the ability to repel both oil and water. Droplets of pump oil, for example, remained in beads on the surface of the coated cotton for months without being absorbed or drawn into the interfiber spaces. When immersed in water, the coated fabric draws a layer of air around itself, which can also stay put for months. Liu tells C&EN that the mechanical properties and breathability of the coated cotton were barely changed from the uncoated fabric, and the coating is extremely stable to laundering.