| 초록 |
A novel strategy for a tunable sigmoidal wetting transition from superhydrophobicity to superhydrophilicity on a continuous nanostructured hybrid film via gradient UV-ozone (UVO) exposure is presented. Along a single wetting gradient surface (40 mm), we could visualize the superhydrophobic (θH2O ＞ 165o and low contact angle hysteresis), transition (165o ＞θH2O ＞10o) and superhydrophilic (θH2O < 10o within 0.5 s or less) regions simply through the optical image of water droplets on the surface. The film is prepared through layer-by-layer assembly of negatively charged silica nanoparticles (11 nm) and positively charged poly(allylamine hydrochloride) with a initial deposition of fractal manner. The extraordinary wetting transition on chemically modified nanoparticle layered surfaces with submicron to microns scale pores represents a competition between chemical wettability and hierarchical roughness of surfaces as often occurs in nature (e.g., lotus leaves, insect’s wings, etc). |
