Preparation and characterization of optical antifogging nano-coating

Abstract

Objective To prepare and test a hydrophilic antifogging nano -coating with favourable stability and antireflective characteristics. Methods Hydrophilic antifogging coating consisted of cationic polyacrylamide (CPAM), sodium silicate and polyacrylic acid (PAA). To obtain a stable multilayer film, the coatings were filmed by layer-by-layer coating method followed with a thermal torrefraction process. The material particle size was measured by a laser particle sizer, lens transmittance prior to and after coating was evaluated by ultraviolet spectrophotometer, coating hydrophilicity was tested by contact angle meter, and coating hardness was determined by pencil test. Results The coating particle size was about (145.0±15.6)nm. In the light spectrum between 400 nm and 800 nm, the transmittance of the coated optical lens was higher than that of the uncoated one, the transmittance peaked at 550 nm wavelength which reached 92.2% . Water drop dispersed completely 470 ms after it contacted with the coating surface. The coating hardness was higher than 3 H. Conclusion The antifogging coating prepared by layer -by -layer method forms stable film structure after thermal torrefaction and improves lens hydrophilicity and transmittence. Key words: Cationic polyacrylamide; Optical antifogging nano-coatings; Layer-by-layer coating method; Transmittance; Hydrophilicity