A Facile Method for Processing Durable and Sustainable Superhydrophobic Chitosan-Based Coatings Derived from Waste Crab Shell
Sunanda Roy, Kheng‐Lim Goh, Chhavi Verma, Barnali Dasgupta Ghosh, Kamal Sharma, Pradip K. Maji
Abstract
The substitution of synthetic raw materials with renewable feedstock is fueling a lot of interest to drive new scientific and technical advancements that underpin this strategy. In this context and looking at the broad prospect of chitosan, herein, we proposed a facile, economical, and novel strategy to process high-yield (44% ± 3) chitosan from waste crab shells and apply the processed chitosan to fabricate a durable, multifunctional, ecofriendly superhydrophobic coating. The coating was developed by binding the amines of chitosan and a long-chain polymer, octadecylamine using a cross-linking agent (glutaraldehyde). Applying the coating onto intrinsically hydrophilic polyester fabric and typical surgical-grade cotton yielded superhydrophobic materials with water contact angles of 158.6 and 161.4° (± 3), respectively. A preliminary study revealed that the coating could endure multiple cycles of laundry (60×), sandpaper abrasion (55×), and tape peel test (80×) with little diminution in the superhydrophobic property. Interestingly, any decrease in the superhydrophobicity could be restored after ironing the fabrics for 2 min, indicating that the effect was reversible. Furthermore, the coating could transform an ordinary hydrophilic polyurethane sponge into an excellent superhydrophobic–superoleophilic absorbent, which can rapidly absorb and separate a variety of organic solvents and oils from oil/water mixtures.