期刊
JOURNAL OF MEMBRANE SCIENCE
卷 308, 期 1-2, 页码 75-86出版社
ELSEVIER
DOI: 10.1016/j.memsci.2007.09.036
关键词
poly(N-isopropylacrylamide); track-etched membranes; aqueous surface-initiated polymerization; microstructure; thermo-responsive behavior
We report on the surface-initiated polymerization by aqueous free radical polymerization (FRP) and atom transfer radical polymerization (ATRP) of N-isopropylacrylamide (NIPAM) from nanopore walls of poly(ethyleneterephthal ate) (PET) membranes. By combining atomic force microscopy and transmission electron microscopy coupled with an electron energy loss detector, we show that grafting polymers from the walls is an efficient process leading to functional and switchable membranes. The thickness of PNIPAM brushes grafted within small and large nanopores could be measured by a template-based method, indicating that confinement impacts strongly the polymerization process. Finally, the temperature-modulated permeability properties of these responsive polymeric systems are evaluated. Depending on the membrane pore size, two types of permeation control mechanisms are observed. For large pore membranes (Phi similar to 330 nm), expanded PNIPAM chains conformations (at T< LCST) result in reduced effective pore size and therefore lower permeabilities relative to collapsed macromolecules chain conformations. In contrast, for narrow pore membranes (Phi similar to 80 nm), the PNIPAM layer grafted at the surface of the membrane becomes the rate-control ling factor; the expanded PNIPAM brush represents greater degrees of hydration in the surface layer and therefore gives rise to higher permeabilities than the collapsed conformation. In this situation, the overall permeability is thus comparable to that of a hydrogel membrane. (c) 2007 Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据