Highly efficient antifogging/antimicrobial dual-functional chitosan based coating for optical devices

The coating is frequently adopted to modify the product surface without influencing the essential features of the pristine products. Recently, significant demand has existed for efficient anti-fogging/anti-microbial surfaces in various applications to inhibit microbial growth with high transparency in high-humidity environments, especially in pandemics such as COVID-19. The current study used dual-functional chitosan (Ch) polysaccharide coating with highly hydrophilic properties to be progressively incorporated onto the glass substrates using a simple one-pot technique. Utilizing hot/cold fogging tests and plate count method, the dual-functional Ch/SiO2(3) layer possesses excellent antifogging performance and anti-microbial activity. The hydrogen bonds and electrostatic attractions formed between MSN and Ch result in a higher bound water ratio, as confirmed by the low field nuclear magnetic resonance (LF-NMR). Therefore, based on the chitosan/silica layer, 95 % is the minimum proportion of bound water necessary in the final layer structure to completely inhibit microbial and fogging activities.