초발수 산화아연 나노물질 제작 및 부유성의 광촉매 특성 평가

Abstract

Surface-wetting behaviors have recently attracted significant attention due to their potential application in a variety of areas. Surface wettability is governed by surface roughness and chemical composition

increasing surface roughness and lowering surface energy can remarkably enhance surface water repellency. In superhydrophobic conditions, a water droplet sits unstably on top of the superhydrophobic surface, forming a spherical shape with a contact angle greater than 150°, and rolls away quickly when subjected to gentle vibration. This phenomenon is easily exemplified by the lotus leaf, thus called the “lotus effect”. Inspired by natural superhydrophobicity, artificial superhydrophobic surfaces have been obtained by building a rough topography and modifying the surface by chemical coating with low surface-energy molecules. Herein, a facile approach for the fabrication of a superhydrophobic nanocoating through a simple spin-coating and chemical modification is demonstrated. The resulting coated surface displayed a static water contact angle of 158° and contact angle hysteresis of 1°, showing excellent superhydrophobicity. The surface wettability could be modulated by the number of ZnO nanoparticle coating cycles, which in turn affected surface roughness. Because of its surface-independent characteristics, this method could be applicable to a wide range of substrates including metals, semiconductors, papers, cotton fabrics and even flexible polymer substrates. This superhydrophobic surface showed high stability in thermal and dynamic conditions, which are essential elements for practical applications. Furthermore, the reversible switching of wetting behaviors from the superhydrophilic state to the superhydrophobic state was demonstrated using repeated chemical modification/heat treatment cycles of the coating films. Next, we demonstrate the fabrication of CuS nanoparticle(NP)s/ZnO nanowire(NW)s heterostructures by a two-step solution reaction. A facile successive ionic layer adsorption and reaction (SILAR) method was used to deposit CuS NPs on the hydrothermally grown ZnO NWs array. The photocatalytic properties of CuS/ZnO heterostructure NWs were investigated under visible light irradiation, which exhibited high activities and stabilities for photodegradation of Acid Orange 7(AO7) aqueous solution. Furthermore, superhydrophobic modification of this sample enables nanowires/mesh substrate floatable in solution, which can facilitate selective decomposition of floating pollutants and recycling of the immobilized NWs photocatalyst.