Simple Preparation Method for Hydrophilic/Oleophobic Coatings

This
work provides a simple method to prepare a hydrophilic/oleophobic
coating using polyester filter cloth as the substrate, a mixture of
three hydrophilic polymers (poly­(aspartic acid), poly­(acrylic acid),
and poly­(vinyl alcohol)); SiO2 with an average particle
size of 30 nm is used to improve the surface roughness of the filter
cloth. Then, a long fluorocarbon chain of 1H,1H,2H,2H-perfluorooctyltriethoxysilane
is grafted onto the surface by a vacuum silanization coupling reaction
to obtain hydrophilic/oleophobic properties. The water and hexadecane
contact angles of the treated filter cloth are 3 and 99.8°, respectively.
A separation efficiency of 98% was achieved in hexadecane/water separation.
The durability test shows that the separation efficiency of toward
hexadecane–water mixture remains more than 98% after 20 cycles.
The obtained material also presents a strong underwater antipollution
property when using hexane, rapeseed oil, mineral oil, and pump oil
as model pollutants. For oils with higher viscosity, the separation
efficiency remains above 97%. However, the separation efficiency is
∼80% when treating emulsions.