Fabrication and characterization of transparent underwater superoleophobic coatings based chitin nanofibers and polyvinyl alcohol

Transparent underwater superoleophobic coatings were prepared by blending chitin nanofibers (ChNFs) and polyvinyl alcohol (PVA) and then cross-linked with glutaraldehyde (GA). The interactions among ChNFs, PVA, and GA in the coatings were analyzed via FT-IR and XPS. Results of SEM observation and AFM analysis showed that higher concentrations of ChNFs and GA gave rise to rougher surface and lower transmittance of the coatings. By adjusting ratios of ChNFs, PVA, and GA, the coating surface could possess underwater superoleophobicity with oil (1, 2-dichloroethane) contact angle up to 159.2° and slide angle ~3°, meanwhile, transmittance of the coatings in the wavelength range of 400–800 nm could be maintained between 40% and 90%. This work provides a new route to prepare environmentally friendly transparent underwater superoleophobic coatings.