title: Automatic droplet transportation on a plastic microfluidic device having wettability gradient surface.
abstract: This paper presents a microfluidic device that can automatically transport a droplet on a plastic plate. This device consists of a Cyclo Olefin Polymer (COP) plate and a SiO2 membrane and has wettability gradient surface. Lithographic patterns of hydrophilic SiO2 permitted wettability modification of a hydrophobic COP surface. A series of alternate hydrophobic and hydrophilic wedge-shaped patterns generated a required gradient in wettability. When we dropped a droplet on the wettability gradient surface, it moved along the wettability gradient due to an imbalance between surface tension forces acting on the opposite sides of the droplet edge. The droplet transportation test was carried out using water of 5 μl. As a result, we succeeded in automatically transporting the droplet on the SiO2/COP wettability gradient pattern. We also carried out droplet transportation in an enclosed microchannel for preventing droplet evaporation using DI (Deionized) water of 5 μl. In this case, the droplet was automatically transported by forming the wettability gradient pattern at the top and bottom in an enclosed microchannel without evaporation.
authors: Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 096-8555, Japan.
authors: Y
authors: Y
authors: Nakashima
authors: Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 096-8555, Japan.
authors: Y
authors: Y
authors: Nakanishi
authors: Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Kitakyushu 808-0196, Japan.
authors: T
authors: T
authors: Yasuda
mesh_terms: D001331:Automation; D004867:Equipment Design; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods*; D010969:Plastics / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry; D013500:Surface Tension; D014867:Water / Q000737:chemistry; D017155:Wettability
chemical_list: D010969:Plastics; D014867:Water; D012822:Silicon Dioxide