Correlation between crosslinking efficiency and spatial inhomogeneity in poly(acrylamide) hydrogels
Correlation between crosslinking efficiency and spatial inhomogeneity in poly(acrylamide) hydrogels
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聚丙烯酰胺水凝胶交联效率与空间不均匀性之间的相关性
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
O. Okay
中科院分区：
文献类型：
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作者：
Nermin Orakdogen;O. Okay
本文研究了以丙烯酰胺（AAm）和N，N '-亚甲基双丙烯酰胺（BAAm）为单体，在不同反应条件下制备的聚丙烯酰胺（PAAm）水凝胶的弹性和光散射性能。弹性测试表明，BAAm的交联效率εxl，即形成有效交联的BAAm分数，随着初始单体浓度Co的降低而降低。在Co= 3%时，发现εxl为10-2-10-3，表明水凝胶制备中使用的99 - 99.9%的BAAm浪费在弹性无效连接中。光散射数据的Debye-Bueche分析表明，与凝胶合成条件无关，相关长度λ，即水凝胶中不均匀性的延伸为101 nm。水凝胶中的冻结浓度波动的程度（由η2表示）随着BAAm的交联效率的增加而减小。凝胶的光散射和弹性数据的组合显示了凝胶化过程中浪费的交联剂分子的分数和空间凝胶不均匀性之间的直接相关性。
SummaryElasticity and light scattering measurements were carried out on poly(acrylamide) (PAAm) hydrogels prepared from acrylamide (AAm) and N,N’-methylenebisacrylamide (BAAm) monomers under various reaction conditions. Elasticity tests showed that the crosslinking efficiency of BAAm εxl, that is the fraction of BAAm forming effective crosslinks decreases as the initial monomer concentration Co is decreased. At Co=3%, εxl was found to be 10-2–10-3, indicating that 99 to 99.9% of BAAm used in the hydrogel preparation are wasted in elastically ineffective links. Debye-Bueche analysis of the light scattering data showed that, irrespective of the gel synthesis conditions, the correlation length ξ, that is, the extension of inhomogeneities in the hydrogels is 101 nm. The extent of frozen concentration fluctuations in the hydrogels represented by 〈η2〉 decreases with increasing crosslinking efficiency of BAAm. The combination of the light scattering and the elasticity data of gels shows a direct correlation between the fraction of wasted crosslinker molecules during gelation and the spatial gel inhomogeneity.