Swelling monitorization of poly [(N-isopropylacrylamide)-co-(methacrylic acid)] copolymers by magnetic resonance imaging
Swelling monitorization of poly [(N-isopropylacrylamide)-co-(methacrylic acid)] copolymers by magnetic resonance imaging
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DOI：
10.1021/ma0509513
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发表时间：
2005-08-23
期刊：
影响因子：
5.5
通讯作者：
Barrales-Rienda, JM
中科院分区：
文献类型：
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作者：
Quijada-Garrido, I;Prior-Cabanillas, A;Barrales-Rienda, JM
用磁共振成像(MRI)研究了聚[(N-异丙基丙烯酰胺)-co-(甲基丙烯酸)]P[(N-iPAAm)-co-(MAA)]水凝胶在磷酸盐缓冲溶液(PBS)(PH 7)中的动态溶胀行为。为了确定全球范围内的吸水量，还采用了一种重量法。拍摄的照片提供了关于不同膨胀阶段的水凝胶形态的有价值的信息。通过结合这三种方法的数据，可以清楚地阐明水分吸收的模式。重量膨胀曲线和照片与从水凝胶中央切片上获得的MRI图像获得的信息一致。与均聚物不同，当相应的共聚物水凝胶在酸性条件下(pH=2)浸泡时，它们在pH=7时表现出特征的S型溶胀曲线。此外，从照片上观察到，水凝胶片具有特殊的形貌。在MRI图像中，区分了两个过程，对应于高度膨胀的外部区域，与硬核形成对比，硬核在滞后时间后开始膨胀，这取决于样品的组成。
The dynamic swelling behavior in phosphate buffer solution (PBS) (pH 7) of poly[(N-isopropylacrylamide)-co-(methacrylic acid)] P[(N-iPAAm)-co-(MAA)] hydrogels has been studied by using magnetic resonance imaging (MRI), which provides information at a local level. To determine the water uptake at a global level, a gravimetric technique was also employed. Photographs were taken providing valuable information on the hydrogel morphology at different stages of swelling. By combining the data from these three methods, the pattern of water uptake may be clearly elucidated. The gravimetric swelling curves and photographs were in agreement with the information obtained from MRI images acquired on central slices of the hydrogels. In contrast to the homopolymers, when the corresponding copolymers hydrogels were soaked under acidic conditions (pH 2), they exhibited characteristic sigmoidal swelling curves at pH 7. Furthermore, the hydrogel slabs adopt a peculiar morphology as it was photographically observed. In the MRI images two processes were distinguished, corresponding to a highly swollen external region in contrast to a rigid core which starts to swell after a lag time depending on sample composition.