Chemical Vapor Deposition Based Superelastic and Superhydrophoboic Thermoplastic Polymeric Nanofibrous Aerogels for Water Purification

Developing high-performance, low-cost and large-scale absorbent materials is crucial for the treatment of water pollution caused by pollutants leakage and emission. Herein, superelastic and superhydrophobic thermoplastic polymeric nanofibrous aerogels (NFAs) were created for removal pollutants from water by using a facile and effective method. Poly(vinyl alcohol-co-ethylene) (EVOH) nanofibers fabricated by mass-production techniques were used to construct three-dimensional NFAs through combing freeze-drying process and cross-linking treatment. The optimal parameters for creating EVOH NFAs with good formability and resilience, including composition and ratio of dispersion, dosage of cross-linking agent were obtained through experiments. EVOH nanofibers bonded with each other by glutaraldehyde under acidic conditions to from fibrous network structure in EVOH NFAs. The silane-coated EVOH NFAs were prepared through further modification with vapor-phase methyltrichlorosilane. The deposition of siloxane improved mechanical strength and decreased plastic deformation after 500 cyclic compressions. An asperate fibrous and granular siloxane coating was deposited on the surface of EVOH NFAs. The surface water contact angle increased from 104.4 degrees +/- 4.0 degrees to 152.7 degrees +/- 1.9 degrees, wettability of NFAs transitioned to being superhydrophobic. Silane-coated EVOH NFAs exhibited superior absorption capacity (40-92 g/g) for a variety of organic pollutants. The organic pollutants would be collected and the sorbents could be reused after distillation or squeezing. A successful scale-up of such materials open up a new insight into design polymeric aerogels in low-cost and large-scale with substantial industrial water purification applications.