Robust superhydrophilic antifogging coatings by a facile sol–gel method

In this study, a simple one-step sol–gel process was applied to synthesize SiO₂-based superhydrophilic antifogging coatings on glass substrates. In this process, Si(OH)₄ sol was first prepared and then SiO₂ nanoparticles were added to the sol to form coating solutions. The influence of both the Si(OH)₄ sol and SiO₂ nanoparticle contents on the coating properties was investigated. Their contents have significant effects on the coatings’ properties, including hydrophilicity and surface morphology. The water contact angle of the optimum coating is about 3.4°. Besides, as revealed by the steam test and freeze test, the optimum superhydrophilic coating demonstrates good antifogging properties and an adequate level of mechanical strength as well. Compared to other techniques used to fabricate antifogging coating on glass substrate, the sol–gel-based process developed in this study requires no expensive equipment, and the processing time is largely shortened. Thus, such technique has great potential applications in the field of coating industry.