Generation of uniform photonic balls and colloidal clusters in soft-microfluidic devices = 미세연성유체 소자 내에서 균일한 크기의 광결정구 및 고분자 입자집합체의 제조

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Three-dimensional (3D) colloidal assemblies of sub-micrometer monodisperse latex particles have received much attention recently, because of their potential uses as photonic crystals and photonic molecules. If the shape and size of spherical photonic crystals are well controlled, it can be used in highly reflective paints, light diffusing materials or in electronic paper. And colloidal clusters are applicable to building blocks for novel photonic crystal, sensor technologies and microphotonics because of their morphology dependent resonances (MDRs). In this paper, the fabrication of such uniform colloidal aggregates using soft-microfluidic devices will be discussed. In soft-microfluidic devices, uniform emulsions were generated at regular intervals by droplet break-off at the junction of two microfluidic channels. The balance of surface tension and high shear forces at the leading edge of the water that is perpendicular to the emerging oil flow determines the diameter of droplets and generation frequency. Droplet size is increased as surface tension and flow rate ratio of aqueous phase and oil phase are increased. And polystyrene suspension whose mass concentration is less than 30% is used as aqueous phase, but there is no significant change in flow pattern such a low mass concentration. Generated droplets suspended in oil kept moving along the microchannel and was shrunk down slowly as water was dissolved into the oil phase and if PS suspension solution with adequate concentration is used as aqueous phase, consolidated spherical colloidal aggregates were obtained at the downstream of the microchannel. For high concentration of suspension solution, the number fluctuation was negligibly small and within a few percentages. For low concentration, however, the number fluctuation of colloidal aggregates became significant and the generated colloidal aggregates were not uniform.
Advisors
Yang, Seung-Manresearcher양승만researcher
Description
한국과학기술원 : 생명화학공학과,
Publisher
한국과학기술원
Issue Date
2004
Identifier
238391/325007  / 020023543
Language
eng
Description

학위논문(석사) - 한국과학기술원 : 생명화학공학과, 2004.2, [ vi, 50 p. ]

Keywords

DROP SIZE; SOFT-MICROFLUIDIC DEVICES; PHOTONIC BALLS; 고분자 입자집합체; 광결정구; 미세연성유체소자; COLLOIDAL CLUSTERS

URI
http://hdl.handle.net/10203/29834
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=238391&flag=dissertation
Appears in Collection
CBE-Theses_Master(석사논문)
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