Study On The Preparation Of Honeycomb- Structured, Porous Films By Water Droplet Templating

Recently, ordered mesoporous / micropous porous materials has attracted considerable attentions because of their great interests in many areas such as catalysis, sensors, separating membrane, microreactor, cell culture backing material, and biomedicine.The formation of the regular honeycomb porous films by water droplet templating is one of the great developments in the field of molecular self-assemble. In this method, water droplets act as the template, and it is very easy to form regular honeycomb micropous films. Water droplet templating method has many advantages such as mild experimental conditions, simple experimental procedure. Meanwhile, the water droplets template can be removed easily in ambient temperature. Therefore, water droplet templating method is a nontoxic and easily available method for the formation of the regular honeycomb porous films.In this paper, we have successfully fabricated the honeycomb porous films of Hydrogenated Poly (styrene-b-isoprene-b-styrene) (SEPTON) by water droplet templating method in high humidity atmospheres. CS2, CHCl3, benzene, CH2Cl2, THF, n-hexane, and their mixed solvents are used to fabricate porous films in different experimental conditions. Moreover, the influences on pattern formations of honeycomb porous films are investigated, which included polymer structure, polymer solution concentration, properties of solvent, solution store time, environmental temperature, environmental humidity, temperature and hydrophilic property of substrates, spreading methods. In this paper, Optical Microscope and SEM are used to study the surface morphology of the honeycomb porous films; also Image-Pro Plus is utilized to analyze the pore size and the pore size distribution. The result suggested that the prerequisites for the successful formation of honeycomb porous films are high humidity atmospheres and certain concentration of polymer solution. The regular honeycomb porous films can be only formed from the polymer solution with proper concentration, and the increase in the concentration of polymer results in a decrease in the pore size. Good compatibility between the polymers and their solvents, and the appropriate volatility of the solvent were beneficial to the formation of regular structures. The pore size increases concomitantly with humidity, and decreases concomitantly with temperature. The regularity of honeycomb porous films is influenced by the temperature of substrate severely. For polymer solution with certain concentration, pore size and pattern of honeycomb films prepared on substrate with different temperature and different hydrophilic property are distinctively different.