Conference Paper Preparation and hydrophobicity of solid/liquid bulk composite using porous glass and low-surface-energy oil

横山, 広大  ,  Yokoyama, Kouta  ,  高田, 康寛  ,  Takada, Yasuhiro  ,  酒井, 宗寿  ,  SAKAI, Munetoshi  ,  磯部, 敏宏  ,  Isobe, Toshihiro  ,  松下, 祥子  ,  Matsushita, Sachiko  ,  中島, 章  ,  Nakajima, Akira

Recently, a new bulk composite material prepared by impregnating low-surface-energy liquid into hydrophobic porous solid with interconnected pore structure was proposed. In the present study, we prepared the composites using a commercial porous glass and fluorinated or silicone oil, then investigated their static and dynamic hydrophobicity by changing oil viscosity and solid surface tension. Various hydrophobic glass plates (average pore size: ~1 mm) were prepared by coating hydrophobic silanes onto the porous glass with or without surface modification by colloidal silica (~100 nm). Porous glass/fluorinated oil bulk composites were prepared by subsequent impregnating two fluorinated oils with different viscosity and a similar surface energy. The composites provided a smaller sliding angle and a contact angle than those of the sample without impregnating lubricants. The composites possessed excellent sustainability on their small sliding angle under the exposure in turbulent water flow. The composite with high viscosity oil exhibited smaller sliding velocity for a water droplet than that with low viscosity oil. Particle image velocimetry revealed that the dominant sliding mode for water droplets on the composites was slipping. Detailed calculation suggested that viscous dissipation at the wetting ridge (oil meniscus at the three phase contact line) plays an important role on the moving behavior of water droplet on the composites. The motion of the droplet sandwiched between these composites, and the sliding behavior of water powder mixture on the composites will be also presented and discussed.

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