Transparent and Durable SiO2-Containing Superhydrophobic Coatings on Glass

We fabricated novel superhydrophobic coatings based on SiO2 nanoparticles combined with NH2-terminated silicone (SN2) or SN2-modified polyurethane (SN2-prePU) by alternately spin-coating them onto glass slides. The final fabricated surface contained SN2/SiO2 or SN2-prePU/SiO2 bilayers. The conditions of spin-coating method were also explored. SN2-prePU with different SN2/prePU molar ratios were synthesized to study the influence of SN2 ratio on the water contact angles of ultimate spin-coated surfaces. The surface was found to be tunable from hydrophobic to superhydrophobic by choosing SN2-prePU with different SN2/prePU molar ratios or SN2 content. Water droplets easily rolled off on these superhydrophobic surfaces. Surfaces coated with SN2/SiO2 bilayers showed better transparency, whereas surfaces coated with SN2-prePU(2 : 1)/SiO2 bilayers exhibited better durability. Droplets of varied pH were prepared to test the anti-wettability of the coatings. Results showed that the as-coated surfaces had stable superhydrophobicity to droplets with pH values ranging from 1 to 14. (c) 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41500.