Physical properties of hydrogels synthesized from lyotropic liquid crystalline templates
Physical properties of hydrogels synthesized from lyotropic liquid crystalline templates
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DOI：
10.1021/cm021703d
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发表时间：
2003-08-26
影响因子：
8.6
通讯作者：
Guymon, CA
中科院分区：
文献类型：
--
作者：
Lester, CL;Smith, SM;Guymon, CA
近年来，大量的研究集中在通过在溶向液晶（LLC）相中聚合单体来合成纳米结构的水凝胶上。由于具有可控纳米结构的潜力，这些材料在各种应用中显示出巨大的潜力。这项工作描述了光聚合动力学和聚合物纳米结构对LLC模板合成的水凝胶物理性质的影响。丙烯酰胺和2-羟乙基甲基丙烯酸酯（HEMA）在高度有序的LLC相中光聚合速度更快，从而产生更高的分子量聚合物。这些单体在有组织的表面活性剂/水组件中的光聚合可以形成高度有序的聚合水凝胶。最终的物理性质似乎是不同聚合动力学和聚合物纳米结构的函数。纳米结构的聚丙烯酰胺水凝胶比各向同性水凝胶膨胀更快，膨胀程度更大。与各向同性类似物相比，纳米结构聚丙烯酰胺水凝胶的压缩模量也更高。HEMA的光聚合产生纳米结构的水凝胶，尽管一些结构变化是明显的。由于不同的纳米结构，观察到的物理性质有很大的不同。各向同性多hema水凝胶比任何有组织的水凝胶膨胀程度更大，膨胀速度更快。此外，各向同性的多hema水凝胶比在有组织的LLC相中合成的水凝胶具有更高的压缩模量。对于聚hema和聚丙烯酰胺凝胶，不同的纳米结构产生不同的物理性质，这意味着可以通过改变母体LLC相来优化膨胀和机械强度等特性。
Recently, a considerable amount of research has centered on the synthesis of nanostructured hydrogels via the polymerization of monomers in lyotropic liquid crystal (LLC) phases. Because of the potential for controllable nanostructures, these materials have exhibited tremendous potential for a variety of applications. This work describes the impact of photopolymerization kinetics and polymer nanostructure on the physical properties of hydrogels synthesized from LLC templates. Both acrylamide and 2-hydroxyethyl methacrylate (HEMA) photopolymerize more rapidly in the highly ordered LLC phases, resulting in higher molecular weight polymers. The photopolymerization of these monomers in organized surfactant/water assemblies allow formation of highly ordered polymeric hydrogels. The ultimate physical properties appear to be a function of the different polymerization kinetics and polymer nanostructure. Nanostructured polyacrylamide hydrogels swell faster and to a greater extent than isotropic hydrogels. Compressive moduli are also higher for nanostructured polyacrylamide hydrogels when compared to isotropic analogues. The photopolymerization of HEMA results in nanostructured hydrogels, although some structural changes are evident. As a result of the different nanostructures, vastly different physical properties are observed. The isotropic polyHEMA hydrogels swell to a greater extent and considerably faster than any of the organized hydrogels. Additionally, the isotropic polyHEMA hydrogels exhibit higher compressive modulus than the hydrogels synthesized in the organized LLC phases. For both polyHEMA and polyacrylamide gels, different nanostructures produce different physical properties, implying that characteristics such as swelling and mechanical strength can be optimized simply by changing the parent LLC phase.