A rational design of double layer mesoporous polysiloxane coatings for broadband antireflection

For the purpose to realize broadband antireflection on glass substrates, double layer mesoporous polysiloxane coatings were well designed by solving Maxwell equation and prepared through sol-gel dip-coating method using tri-block copolymer (EO20PO70EO20) as porogen. The obtained double layer coatings revealed broadband antireflective performance within wavelength range from 400 to 900 nm with a maximum transmittance of 99.2 % around 520 nm, which was in well agreement with the calculated results. The mesopore structure was confirmed by AFM and N-2 adsorption-desorption measurement. Moreover, it was found that the outer layer of resultant coatings showed increased hydrophobicity along with increased temperature. Hence, we proposed that the condensation degree of silica network played an important role on the surface wettability of polysiloxane coatings, which was fully investigated with the assistance of FT-IR and water contact angle measurements.