This paper reports how a hairy layer of carbon nano-fibers can be prepared on the macro-porous silica foam produced by the sphere templating method. Firstly, three-dimensional close-packed crystals of polystyrene sphe...This paper reports how a hairy layer of carbon nano-fibers can be prepared on the macro-porous silica foam produced by the sphere templating method. Firstly, three-dimensional close-packed crystals of polystyrene spheres are assembled on porous disk substrate by vacuum filtration or evaporation. The polystyrene template is annealed slightly above the glass transition temperature in order to strengthen the colloidal crystal and ensure interconnection of the spheres so as to obtain porous materials with open structure. Following the treatment of hexdecyltrimethylammonium bromide, the polystyrene template is filled with silica colloidal solution, which solidifies in the cavities. Then the polystyrene particles are removed by calcination at 843K, leaving behind porous silica foam. Scanning electron microscopy images demonstrate that silica foam has uniform and open structured pores. Nickel particles were deposited on porous silica foam layer by the dipping method and porous carbon nano-fiber washcoat was prepared by catalytic decomposition of ethene over small nickel particles.展开更多
The role of roughness and composition on the wetting characteristics of a series of carbon nanofiber based coatings were studied in order to evaluate its superhydrophobic properties. In this study, idealized surfaces ...The role of roughness and composition on the wetting characteristics of a series of carbon nanofiber based coatings were studied in order to evaluate its superhydrophobic properties. In this study, idealized surfaces were created from a smooth stainless steel and aluminium sheets and two other stainless steel sheets with different textured surfaces. All surfaces were coated with carbon nanofiber alcohol solutions in order to generate coatings of variable compositions using mixtures of isopropanol, water and a commercial carbon nanofibre. The optimum concentration of carbon nanofiber in coatings was obtained to produce superhydrophobic surfaces. A general trend of increasing hydrophobicity was observed for coated surfaces as compared to the bare substrate. Individual contact angles were dependent on the nature of the underlying substrate, relative surface pattern, and roughness. Overall wetting properties were dependent upon composition and micro scale roughness of the coatings.展开更多
文摘This paper reports how a hairy layer of carbon nano-fibers can be prepared on the macro-porous silica foam produced by the sphere templating method. Firstly, three-dimensional close-packed crystals of polystyrene spheres are assembled on porous disk substrate by vacuum filtration or evaporation. The polystyrene template is annealed slightly above the glass transition temperature in order to strengthen the colloidal crystal and ensure interconnection of the spheres so as to obtain porous materials with open structure. Following the treatment of hexdecyltrimethylammonium bromide, the polystyrene template is filled with silica colloidal solution, which solidifies in the cavities. Then the polystyrene particles are removed by calcination at 843K, leaving behind porous silica foam. Scanning electron microscopy images demonstrate that silica foam has uniform and open structured pores. Nickel particles were deposited on porous silica foam layer by the dipping method and porous carbon nano-fiber washcoat was prepared by catalytic decomposition of ethene over small nickel particles.
文摘The role of roughness and composition on the wetting characteristics of a series of carbon nanofiber based coatings were studied in order to evaluate its superhydrophobic properties. In this study, idealized surfaces were created from a smooth stainless steel and aluminium sheets and two other stainless steel sheets with different textured surfaces. All surfaces were coated with carbon nanofiber alcohol solutions in order to generate coatings of variable compositions using mixtures of isopropanol, water and a commercial carbon nanofibre. The optimum concentration of carbon nanofiber in coatings was obtained to produce superhydrophobic surfaces. A general trend of increasing hydrophobicity was observed for coated surfaces as compared to the bare substrate. Individual contact angles were dependent on the nature of the underlying substrate, relative surface pattern, and roughness. Overall wetting properties were dependent upon composition and micro scale roughness of the coatings.
