SWELLING DESWELLING OF ANIONIC COPOLYMER GELS
SWELLING DESWELLING OF ANIONIC COPOLYMER GELS
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DOI：
10.1016/0142-9612(95)91130-q
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发表时间：
1995-05-01
期刊：
影响因子：
14
通讯作者：
PEPPAS, NA
中科院分区：
文献类型：
--
作者：
KHARE, AR;PEPPAS, NA
离子凝胶动态和平衡溶胀的研究对于了解生理学上重要的流体在特定位点受控药物输送应用的材料中的扩散非常重要。研究了干燥玻璃状聚(甲基丙烯酸2-羟乙酯-共聚-丙烯酸)和聚(甲基丙烯酸2-羟乙酯-共聚-丙烯酸)聚合物网络的动态和平衡溶胀特性作为pH、离子强度、抗衡离子性质和缓冲组合物的函数。随着溶胀介质 pH 值的增加以及在恒定 pH 值大于或等于 pK(a,gel) 时离子强度的降低，这些凝胶中的水扩散机制变得更加反常。在 pH 4.0（低于 pK(a,gel)）的所有无缓冲溶胀介质中，水扩散机制均为 Fickian。这些凝胶的 pK(a,gel) 介于 5.5 和 6 之间。在 pH 4.0 时，扩散机制与离子强度无关。这种膨胀行为可以用离子渗透膨胀压和离子交换动力学的概念来解释。
Studies of dynamic and equilibrium swelling of ionic gels are important in understanding the diffusion of physiologically important fluids in materials for site-specific controlled drug delivery applications. The dynamic and equilibrium swelling properties of dry glassy poly(2-hydroxyethyl methacrylate-co-methacrylic acid) and poly(2-hydroxyethyl methacrylate-co-acrylic acid) polymeric networks were studied as a function of pH, ionic strength, nature of the counterion and buffer composition. The mechanism of water diffusion in these gels became more anomalous as the pH of the swelling medium increased and as the ionic strength decreased at a constant pH greater than or equal to pK(a,gel). The mechanism of water diffusion was Fickian in all unbuffered swelling media at pH 4.0, which is lower than the pK(a,gel). The pK(a,gel) of these gels was between 5.5 and 6. At pH 4.0, the diffusion mechanism was independent of ionic strength. This swelling behaviour is explained in terms of the concept of ion osmotic swelling pressure and ion exchange kinetics.