High transmittance superhydrophilic thin film with superior mechanical properties

A two-layer structure of superhydrophilic thin film with high transmittance and superior mechanical properties was fabricated and developed. Superhydrophilic thin film has been deposited on a pre-coated anti-reflection coating substrate. The average transmittance in the visible range (400-700 nm) was increased from 91.3 ± 0.1% to 94.2 ± 0.1%, because an anti-reflection coating was inserted between the superhydrophilic thin film and substrate. In particular, the mechanical properties of the high transmittance superhydrophilic thin film were also deeply investigated in this paper. The hardness of the thin film was greater than 3H. The superhydrophilic property was maintained after the thin film was pressed by a 500 g weight steel wool and moved back and forth for more than 100 times. According to ISO 2409 standard, the adhesion of the thin film is given a quality of rank 1. The water contact angle of the thin film was less than 10° after ultraviolet light irradiation and the superhydrophilicity was maintained for 76 h when stored in a dark place. The high transmittance superhydrophilic thin film with superior mechanical properties can be utilized in optical, environmental, superhydrophilic and photocatalytic applications.