Super hydrophobic property of PVDF/CaCC>3 nanocomposlte coatings

摘要

There has been a continuous demand for water-repellent or hydrophobic coatings in industry, especially for super hydrophobic coatings which present water contact angles greater than 150". Wettability of solid surfaces with water is known to be influenced by two main factors, i.e., surface chemistry and surface topography [1, 2]. A perfect example from nature is the lotus leaf, on which a water droplet apparently forms a sphere, unstably sitting on the leaf, and dirt is easily removed with a rain shower. This is also called "lotus effect" or "self-cleaning effect." There are many other plant leaves which possess this property such as cabbage, kohlrabi and gingko. The self cleaning mechanisms of these leaves are mainly based on epicutic-ular wax crystals in combination with papillose epidermal cells, which form a very hydrophobic top-layer of a structured surface [3J. The mechanisms in these super water repellent leaves has been recognized by scientists and many efforts have been made in topography design and its application onto a certain substrate. Various techniques have been applied, including microwave plasma-enhanced chemical vapor deposition (MWPE-CVD) of trimethylmethoxysilane (TMMOS) [4], anodic oxidization of aluminum [1], solidification of melted alkylketene dimmer [5], phase separation [6j, hot water immersion of sol-gel alumina [7]. However, those techniques of embossing a certain texture onto a surface are either too complex or not cost-effective.