Recyclable superhydrophobic nanocomposites with electrical conductivity
摘要：Bioinspired superhydrophobic treatment imparts unique features to surfaces such as selfcleaning, low drag, anti-icing, anti-fouling, etc. However, surface treatments are susceptible to damage on prolonged usage. Here, we report a new class of superhydrophobic composite materials with good structural properties and electrical conductivity. These composites also recover their superhydrophobicity after undergoing molding based recycling processes, thereby offering promise of long life and re-usability. The composites comprise of carbon fiber（CF） reinforced poly（vinylidene fluoride）（PVDF）, with carbon black（CB） and cerium oxide（Ce O2） nanoparticle fillers and were manufactured via a standard molding approach typically used to make carbon fiber reinforced plastic（CFRP） composites, without any further treatments. The hydrophobicity of the composites was assessed using water droplet contact angle（WCA） and sliding angle（WSA） measurements, and drop impact tests. Addition of only CeO2 nanoparticle fillers was adequate to achieve superhydrophobicity. However, with addition of < 4 wt.% of CB both hydrophobicity and conductivity improved; water contact angles（WCA） rose from ～151°（without CB） to ～156° and conductivity from 4.7 S/cm to 6.8 S/cm. By adjusting the filler content, the composite tensile strength could be tuned from 79.4 MPa to 108.9 MPa, while retaining superhydrophobicity and tensile modulus of ～10 GPa. The recyclability of the superhydrophobic CFRP was established through three different methods: molding the CFRP scraps or its ground powder, or remolding prepregs from the powder followed by molding. Each approach regenerated superhydrophobicity. Lastly, the composites were also superoleophilic, which should enable their potential exploitation in oil-water separation.