Facile Formation of Durable SiO₂-TiO₂ Coatings on Plastic Films for Self-Cleaning and Antifogging

Surface fogging affects the light transmittance of various transparent materials and poses potential safety hazards. Superhydrophilic TiO₂ surfaces can effectively prevent fogging by promoting continuous water film formation; however, they often struggle to maintain stable hydrophilicity and adhesion on plastic films. Self-cleaning and antifogging coatings on plastic substrates are crucial for applications requiring long-term clarity and minimal maintenance costs. Herein, we present a nanostructured SiO₂-TiO₂ coating, developed using sol-gel and spray coating methods, specifically designed for plastic films. The coated plastic films exhibit a high optical transmittance of 89.8% and superhydrophilicity with an optimal thickness of 70 nm. Notably, these coated films maintain their superhydrophilicity without the need for ultraviolet irradiation, providing continuous fogging prevention and effective degradation of adsorbed organic matter for self-cleaning. Furthermore, the SiO₂-TiO₂ coating can adhere stably to substrates and resist solution soaking, showing great mechanical stability. This straightforward method of creating self-cleaning superhydrophilic coatings on plastic substrates underscores its critical role in large-scale applications, where maintaining clarity and cleanliness is paramount. These applications span packaging films, greenhouse covers, and resin lenses, where durability and ease of upkeep are of the utmost importance.