Chemical stable, superhydrophobic and self-cleaning fabrics prepared by two-step coating of a polytetrafluoroethylene membrane and silica nanoparticles

A superhydrophobic aramid fabric with a novel self-cleaning ability and excellent chemical stability was prepared by the two-step coating technique using an easily available material system consisting of a polytetrafluoroethylene (PTFE) membrane, particles of PTFE and silica (SiO2). The chemical resistant layer was achieved through compounding aramid fabric with the PTFE membrane, for which the contact angle was varied from completely infiltrating to 130 degrees. Then the PTFE-coated fabric was modified with PTFE and SiO2 particles to obtain the superhydrophobic layer. The hydrophobicity was significantly enhanced with a contact angle of 154 degrees and rolling angle of 4 degrees due to the role of low surface energy and rough micro/nano structures. Furthermore, the PTFE/SiO2-coated fabric eventually fabricated could withstand at least 300 cycles of abrasion and strong acid/alkaline attacks for 100 hours. In addition, the breathable performance and flexibility of the coated fabric were within our acceptable ranges. The simple but effective PTFE/SiO2-coated fabric may be useful for the development of individual protective clothing for emergency rescue applications.