Ultrathin, cross-linked polyimide pervaporation membranes prepared from polyelectrolyte multilayers
Ultrathin, cross-linked polyimide pervaporation membranes prepared from polyelectrolyte multilayers
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DOI：
10.1016/j.memsci.2004.09.029
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发表时间：
2005-02-15
影响因子：
9.5
通讯作者：
Bruening, ML
中科院分区：
文献类型：
--
作者：
Sullivan, DM;Bruening, ML
聚酰胺酸盐和聚阳离子在多孔氧化铝载体上的交替静电吸附，然后热诱导亚胺化，可以得到超薄的聚酰亚胺薄膜。此外，在聚酰胺酸中加入额外的羧酸基团允许通过这些基团与聚阳离子的胺反应进行交联。FTIR光谱证实在250℃加热2小时后完全亚胺化并形成了酰胺交联，而扫描电子显微镜显示均匀的、类似于50 nm厚的基于7.5-12.5聚酰胺酸/聚阳离子双层的薄膜。通过改变聚阳离子，即聚烯丙基胺盐酸盐、聚乙烯亚胺或聚二烯丙基二甲基氯化铵，或改变聚酰胺酸中可交联基的数目，研究了渗透汽化作为交联度的函数。由聚烯丙基胺盐酸盐和在每个重复单元中含有二氨基苯甲酸的聚酰胺酸制备的亚胺化薄膜具有最大的交联性和选择性。这种膜对含有10%和90%异丙醇的溶液分别表现出1100和6100的水/醇选择性，并且多层膜的最小厚度仍然允许这些选择性分别在11和2 kg m(-2)h(-1)的通量下发生。对于水/乙醇溶液，通量基本相同，但对10%和90%乙醇的选择性分别降低到100和500。(C)2004爱思唯尔B.V.保留所有权利。
Alternating electrostatic adsorption of poly(amic acid) salts and polycations on porous alumina supports followed by heat-induced imidization yields ultrathin, polyimide membranes. Moreover, incorporation of additional carboxylic acid groups in the poly(amic acid) allows cross-linking via reaction of these groups with the amines of the polycation. FTIR spectroscopy confirms both full imidization and formation of amide cross-links after heating at 250 C for 2 h, while scanning electron microscopy reveals uniform, similar to50 nm thick films based on 7.5-12.5 poly(amic acid)/polycation bilayers. Pervaporation was investigated as a function of cross-linking by varying either the polycation, i.e., poly(allylamine hydrochloride), polyethylenimine, or poly(diallyldimethylammonium chloride), or the number of cross-linkable groups in the poly(amic acid). Maximum cross-linkage and selectivities occur with imidized films prepared from poly(allylamine hydrochloride) and a poly(amic acid) that contains diaminobenzoic acid in each repeat unit. Such membranes exhibit water/alcohol selectivities of 1100 and 6100 for solutions containing 10 and 90% isopropanol, respectively, and the minimal thickness of the multilayer films still allows these selectivities to occur at fluxes of 11 and 2 kg m(-2) h(-1), respectively. Fluxes are essentially the same for water/ethanol solutions, but selectivities decrease to 100 and 500 for 10 and 90% ethanol, respectively. (C) 2004 Elsevier B.V. All rights reserved.