Preparation of the multifunctional antireflective films from a templating composite silica sol with entwining structures

Antireflective (AR) films were prepared by the sol-gel method and dip-coating process by using tetraethylorthosilicate (TEOS) as silica precursor. Silica nanoparticle (SiO2-NP) sol was first synthesized via classical Stöber method, and then SiO2-NPs in sol were chained in series by linear silicate polymers (SiO2-LPs) to improve the film abrasion-resistant property. To further increase the transmittance of the SiO2-LP/NP composite film, the template agent CTAB was introduced into the SiO2-LP/NP composite sol. The experimental results revealed that the abrasion-resistant property had been enhanced with the increase of SiO2-LPs addition and the pencil hardness of the composite film had reached 6H when the mole ratio of SiO2-LPs to SiO2-NPs was 0.7:1. Meanwhile, the transmittance was optimized when nCTAB:nLPs was equal to 0.15:1 in the composite sol, and at this mole ratio the average transmittance of the glass substrate coated with AR film was about 98.5% in the wavelength range of 400-800 nm, while that of the bare glass substrate was just 91.5%. Trimethylchlorosilane (TMCS) treatment was finally used to provide AR films with hydrophobicity. The water contact angle was significantly increased from 6° to 120° after TMCS treatment, affording the AR films excellent environmental resistance.