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Preparation of Patterned Isopore Poly(urethane acrylate) and Microporous Poly(vinylidene fluoride) Membranes by Soft Lithography and Their Application to Water Treatment
소프트 리소그래피 방법을 이용한 패턴형 등방공경 PUA 분리막과 패턴형 PVDF 정밀여과막의 제작 및 수처리에의 적용

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Authors
최동찬
Advisor
이정학
Major
공과대학 화학생물공학부
Issue Date
2015-08
Publisher
서울대학교 대학원
Keywords
Isopore membranePatterned membraneAnti-foulingParticle depositionThree dimensional modelingSoft lithographyShear stressVortex
Description
학위논문 (박사)-- 서울대학교 대학원 : 화학생물공학부, 2015. 8. 이정학.
Abstract
Membrane filtration process is widely used for water and wastewater treatments because of numerous advantages it offers. Critical issues in membrane processes are membrane fouling as well as broad pore size distribution. In this study, patterned isopore membrane with high fouling resistance was fabricated combining soft lithographic method with UV-curable polymer and the effect of pattern on particle deposition were elucidated.
First, membrane with uniform pore size was fabricated using a soft-lithographic method. Due to the precisely controlled pore size by micro size patterns, the membrane presented narrow pore size distribution comparing with conventional membrane. Furthermore, because the UV-curable polyurethane acrylate with releasing agent which decreases surface energy of PUA was used as the membrane material, it gave rise to better anti-biofouling performance than materials of commercial isopore membrane such as polycarbonate.
Second, a patterned isopore membrane with reverse-pyramid patterns was prepared from UV-curable polyurethane acrylate by the soft lithographic method and extent of particle deposition was investigated during microfiltration. The extent of particle deposition was dependent on not only the ratio of crossflow velocity to permeation velocity, but also the size of particles in the feed. Three dimensional modeling based on computational fluid dynamics was also conducted to predict the vortex formation and elucidate the anti-fouling mechanisms of reverse-pyramid patterned membranes. The vortex was in accordance with the trends of particle depositions during the microfiltration.
Third, correlations between pattern shape and extent of particle deposition were investigated experimentally and were elucidated through three dimensional modeling. The extent of particle deposition on patterned membranes was dependent on both pattern shape and orientation. Three dimensional modeling predicted velocity profile and shear stress distribution on patterned membrane surface. The changes in hydraulic trait at each pattern affected particle deposition. In particular, maximum shear stress mostly governed the extent of particle depositions on the membrane surface.
Language
English
URI
https://hdl.handle.net/10371/119749
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College of Engineering/Engineering Practice School (공과대학/대학원)Dept. of Chemical and Biological Engineering (화학생물공학부)Theses (Ph.D. / Sc.D._화학생물공학부)
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