Fabrication of simple bio-friendly hydrophobic coatings via protein denaturation and etching by NaCl

The author reports on the technology to make a simple hydrophobic coating that is bio and eco-friendly. Former hydrophobic surfaces are made of metal or plastic. They are not bio﹠eco-friendly. So edible coating made of polysaccharides, proteins and lipids is emerged. Especially, polysaccharide and protein coatings have excellent mechanical and structural characteristics, but their ability to block moisture is poor due to their hydrophilic properties. To overcome such a problem, this study aims to fabricate hydrophobic protein coatings. NaCl is used to make micro/nano-sized structure by etching and induces protein denaturation that hydrophobic area is exposed. It is a simple process because NaCl is used to manipulate two condition at the same time. Finally, it is able to successfully make a hydrophobic protein coating with a contact angle of 117.7°.