Pore assembled multilayers of charged polypeptides in microporous membranes for ion separation.
Pore assembled multilayers of charged polypeptides in microporous membranes for ion separation.
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DOI：
10.1021/la049688
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发表时间：
2004-05
期刊：
影响因子：
--
通讯作者：
A. Hollman;D. Bhattacharyya
中科院分区：
文献类型：
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作者：
A. Hollman;D. Bhattacharyya
在这项研究中，通过将聚电解质多层网络固定在微孔(孔径为0.2微米)载体的内部孔结构中，制备了高渗透离子选择膜。静电逐层组装是通过在对流条件下交替吸附阳离子和阴离子聚电解质来实现的。为了启动孔组装，第一层由共价结合的带电多肽(聚(L-谷氨酸)或聚(L-赖氨酸))组成，为后续的吸附建立带电载体。在受限的孔几何结构内非化学计量固定带电多层膜导致膜相中可电离基团的体积密度增加。有效电荷密度的整体增加允许使用渗透率值超过传统膜工艺的微孔材料来排除离子物种(特别是二价共离子)。使用PLGA/PLL和合成聚电解质(聚苯乙烯磺酸盐/聚烯丙基胺)来制备多层组件，试图比较所得到的材料的吸附和分离性能的水平。考察了载体溶剂中盐浓度对聚电解质总吸附的影响，以确定其对溶质(Cl-、SO4(2-)、As(V))和水传输的影响。在沉积过程的每个阶段，通过渗透率测量和葡聚糖抑制研究，监测了多层传播引起的孔尺寸收缩。
In this study, highly permeable ion-selective membranes are prepared via immobilization of polyelectrolyte multilayer networks within the inner pore structure of a microporous (pore size = 0.2 microm) support. Electrostatic layer-by-layer assembly is achieved through alternate adsorption of cationic and anionic polyelectrolytes under convective flow conditions. To initiate pore assembly, the first layer consists of covalently bound charged polypeptides (poly(L-glutamic acid) (PLGA) or poly(L-lysine) (PLL)) establishing a charged support for subsequent adsorption. Nonstoichiometric immobilization of charged multilayers within a confined pore geometry leads to an enhanced volume density of ionizable groups in the membrane phase. This overall increase in the effective charge density allows for Donnan exclusion of ionic species (especially divalent co-ions) using microporous materials characterized by permeability values that exceed conventional membrane processes. Multilayer assemblies are fabricated using both PLGA/PLL and synthetic polyelectrolytes (poly(styrenesulfonate)/poly(allylamine)) in an attempt to compare the level of adsorption and separation properties of the resulting materials. The role of salt concentration in the carrier solvent on overall polyelectrolyte adsorption was examined to determine its effect on both solute (Cl-, SO4(2-), As(V)) and water transport. Constriction of the pore size induced by multilayer propagation was monitored through permeability measurements and dextran rejection studies at each stage of the deposition process.