D-O-012-溶剂可逆型(Solvent-reversible)多孔聚合物材料研制-严 锋

溶剂可逆型(Solvent-reversible)多孔聚合物材料的研制
严 锋1 俞绍玫1 路建美1 John Texter 2
1
苏州大学化学化工学院， 215123;
2 School of Engineering Technology, Eastern Michigan University, Ypsilanti, MI, 48197
关键词：微乳液聚合，离子液体，多孔材料，溶剂可逆
离子液体是完全由阴、阳离子构成，在低于100o C 下呈液态的物质。

与传统的有机溶剂和电解质相比，离子液体具有蒸气压低、化学稳定性以及热稳定性优异的特性，因此，被称之为“绿色溶剂”。

[1-3] 目前，离子液体在高分子科学领域中的一个主要应用是作聚合反应(如ATRP, RAFT 等反应)溶剂。

[4,5]
本课题组利用基于离子液体的微乳液聚合制备了溶剂可逆型(Solvent- reversible) 多孔聚合物材料的并对其性质进行表征： N N O O Br -IL-Br N N O
O
BF 4-IL-BF 4
Figure 1. Syntheses of IL-Br and IL-BF 4 IL surfactants. 11-Bromoundecanol is first acrylated. The resulting bromoundecylacrylate a is then quaternarized with methylimidazole to give IL-Br . Ion
Figure 2. Phase diagram (weight fraction) of IL-BF4/aqueous propanol/MMA systems at 24o C,
shadowed area shows two-phase region.
我们首先合成了可聚合型甲基咪唑离子液体乳化剂(Figure 1)，并成功配制了微乳液体系(Figure 2)。

在适当组分配比下的微乳液聚合得到聚(离子液体/甲基丙烯酸甲酯) 共聚物水凝胶。

离子液体共聚物保留了离子液体的特性和微乳液体系所有的纳米微结构。

Figure 3. SEM images of polymers: (A) after microemulsion polymerization (IL-BF4, MMA, 1-propanol, H2O at 15:15:35:35 weight ratio plus EGDMA at 2 wt% by weight with respect to other components); (B) gel in (A) treated with aqueous 0.1M KPF6; (C) gel in (B) treated with aqueous DMSO; (D) gel in (C) treated with water; (E) after 3 cyclic treatments of aqueous DMSO/water; (F) after 7 cyclic treatments of aqueous DMSO/water.
共聚物水凝胶经KPF6水溶液处理后，共聚物中离子液体结构单元的阴离子由Br-转变为PF6-，聚合物由亲水性水凝胶(Figure 3A)转变为疏水材料，并在水溶液中收缩形成多孔结构材料(Figure 3B)。

该多孔聚合物材料在DMSO等有机溶剂中能够被“修复” 成聚合物凝胶(Figure 3C)；“修复”后的聚合物凝胶在水溶液中再次生成多孔结构材料(Figure 3D)。

这种凝胶/多孔结构可以在DMSO/水体系中多次循环生成(Figure 3E、F)，被称为“溶剂可逆型”多孔聚合物材料。

通过调节微乳液体系的组成，可以将多孔聚合物孔径控制在50-200 nm之间。

W e i g h t w t %Temperature o C
Figure 4. TGA analysis of copoly(IL-BF 4/MMA) samples with different crosslinker
(EGDMA) contents and of a precursor polymer gel.
另外，离子液体与甲基丙烯酸甲酯的共聚大大提高了聚合物的热稳定性
（Figure 4）。

该材料在控制释放、组织工程等领域有着潜在的应用价值。

参考文献
1 T. Welton, C hem. Rev ., 1999, 99, 2071. 2
J. Dupont, R. F. de Souza, P. A. Z. Suarez, C hem. Rev ., 2002, 102, 3667. 3
P. Wasserscheid, W. Keim, Angew. Chem., Int. Ed., 2000, 39, 3772. 4
H. Zhang, K. Hong, J. W. Mays, Macromolecules , 2002, 35, 5738. 5 S. Ding, M. Radosz, Y. Shen, Macromolecule , 2005, 38, 5921.
Solvent-Reversible Poration in Ionic Liquid Copolymers
Feng Yan,1 Shaomei Yu, 1 Jianmei Lu,1 John Texter 2
1 Key Laboratory of Organic Synthesis of Jiangsu Province, School of Chemistry and
Chemical Engineering, Suzhou University, Suzhou 215123, China. 2School of
Engineering Technology, Eastern Michigan University, Ypsilanti, MI, 48197, USA
Abstract A new class of hydrogel/solvogel copolymers have been derived by microemulsion polymerization of methacrylates and reactive ionic liquid surfactants in aqueous/methacrylate/surfactant microemulsions. Depending on the cross-linking density, the resulting gels (transparent or translucent) can be reversibly transformed into microporous or nanoporous materials with open cell structures via spinodal
decomposition of the gel phases. Reversibility is aided by the cross-linking. The spinodal decomposition is induced by changing the solvent quality from good to poor for the copolymeric blocks containing the polymerized ionic liquid surfactant. With suitable cross-linking such materials may also provide porous fabric coatings for repelling water while allowing vapor to freely permeate.
Key Words：microemulsion polymerization，ionic liquid，porous materials，solvent-reversible。