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Inverse colloidal crystal membranes: formation, surface modification and applications

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dc.contributor.authorWang, Xinying, author
dc.contributor.authorWickramasinghe, Sumith Ranil, advisor
dc.contributor.authorHusson, Scott Michael, committee member
dc.contributor.authorBailey, Travis Slade, committee member
dc.contributor.authorQian, Xianghong, committee member
dc.date.accessioned2007-01-03T04:51:46Z
dc.date.available2007-01-03T04:51:46Z
dc.date.issued2010
dc.description.abstractInverse colloidal crystal (ICC) membranes have many advantages, such as highly uniform pore size, fully interconnected pores, and high porosity, over commercially available porous membranes as a selective barrier for ultrafiltration and microfiltration. However, making an ICC membrane which is applicable in separations using reported ICC membrane formation methods has been still not successful yet. We describe here a new ICC membrane formation method, vertical cell (VC) assembly method, to make ICC separation membranes in a simple, low-cost way. The VC assembly method is a versatile colloidal crystal assembly method which is specifically designed for making ICC membranes. Formation of colloidal crystal films(CCF), which is the first step in formation of the inverse colloidal crystal membrane, to large extent determines how good the final membrane properties. The vertical cell assembly method is described that yields CCFs with surface areas up to 5 cm2 and thicknesses up to 100 μm. The thickness of the CCF can also be easily controlled by the spacer which is used. Based on the new ICC membrane formation method, the ICC membranes have been fabricated with a variation of pore-sizes and thicknesses. The membrane casting cell facilitates easy variation of membrane thickness. The membrane pore size is varied by changing the diameter of the silica spheres used to prepare the colloidal crystal template. By changing the composition of the reactive monomer solution, the ICC membranes have been fabricated with different hydrophobicities. Following synthesis, the ICC membranes were tested in a commercially available stirred cell. Particle fractionation was studied in normal flow filtration experiments. The membrane produced from 835 nm particles and 100 μm spacer gives a good passage for 60 nm particles in 60-835 nm bidisperse particle suspension while gives poor passage for the same size paritcles in 60-440 nm bidisperse particle suspension. Fabrication of a UF membrane requires a much smaller pore size. However, for making the ICC membranes with pore size in UF range, it is hard to make them just relying on using small SiO2 particles. This would lead to poor membrane mechanical strength. Here, I described a way to reduce the ICC membrane pore size by growing a uniform poly (poly ethylene glycol methacrylate) (PPEGMA) nano-layer from the membrane surface using surface initiated atom transfer radical polymerization. There are two purposes for the surface modification. One is to control membrane pore size. The other is to improve the membrane surface hydrophobicity. The grafted membranes were characterized with SEM, XPS, ATR-FTIR and water contact angle measurement. Dextran rejection test was conducted on the modified membrane with modification time of 3hr. The rejection rate was obtained for dextran with Mw from 1 kDa through 2000 kDa. The tested membrane shows more than 80% rejection for Dextran with MW more than 100 kDa, and a partial rejection for Dextran with Mw from 10 kDa to 100 kDa, and a less than 20% rejection for Dextran with MW smaller than 10kDa.
dc.format.mediumborn digital
dc.format.mediumdoctoral dissertations
dc.identifierWang_colostate_0053A_10173.pdf
dc.identifierETDF2010100001CABE
dc.identifier.urihttp://hdl.handle.net/10217/44879
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relation.ispartof2000-2019
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.
dc.subjectultrafiltration
dc.subjectsurface modification
dc.subjectmicrofiltration
dc.subjectmembrane separation
dc.subjectinverse colloidal crystal
dc.subjectATRP
dc.subject.lcshMembrane separation
dc.subject.lcshUltrafiltration
dc.subject.lcshLiquid crystal films
dc.subject.lcshColloidal crystals
dc.subject.lcshNanostructured materials
dc.subject.lcshMembranes (Technology)
dc.titleInverse colloidal crystal membranes: formation, surface modification and applications
dc.typeText
dcterms.rights.dplaThis Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
thesis.degree.disciplineChemical and Biological Engineering
thesis.degree.grantorColorado State University
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy (Ph.D.)

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