Deposition Of One-Dimensional Nanomaterials For Underwater Superoleophobic Surface Fabrication And Application

Surfaces with superoleophobicity underwater gain worldwide attention in recent years for their extensive applications in oil/water separation, anti-bioadhesion, self-cleaning and oil/water interface drag deduction. It is universally acknowledged that hydrophilic chemical composition and hierarchically rough morphology are key factors in realizing this wettability. One-dimensional nanomaterials are excellent candidates in fabricating underwater superoleophobic surfaces, as long as they are hydrophilic in air.Multi-walled carbon nanotubes (MWCNTs) were facilely decorated with tannic acid (TA) and the MWCNTs/TA dispersion was vacuum-filtrated to fabricate carbonaceous coatings with superoleophobicity and ultra-low oil adhesion underwater (OCA= 164.8°, SA= 2.7°). The super-oil-repellent property can be well maintained for long-term use, even in strong acidic, alkaline or saline environments. The TA molecules on the coatings can be washed away by organic solvents and adsorb to the surface again, making the surface interchangeable in wettability. Based on the superoleophobicity underwater, the TA-decorated MWCNTs coating has been successfully used in oil/water separation. Moreover, the decoration of TA endows the coating with other functions such as protein immobilization, hydroxyl apatite growing, silver nanoparticles loading and iron minerals deposition.Electrospinning is a common method in preparing nanofiberous materials. Chitosan/polyethylene oxide (PEO) blend was electrospun into a nanofiber mat with superoleophobicity underwater. A series of factors were optimized for the preparation process, such as the acetic acid concentration, the molecular weight of PEO and the ratio between chitosan and PEO. The electrospinning of silk fibroin was studied as well. A novel solution was proposed to enhance the repeatability of the experiment.