Influence of polymerization conditions on the structure of temperature-sensitive poly(N-isopropylacrylamide) microgels
Influence of polymerization conditions on the structure of temperature-sensitive poly(N-isopropylacrylamide) microgels
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DOI：
10.1021/ma047776v
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发表时间：
2005-02-22
期刊：
影响因子：
5.5
通讯作者：
Richtering, W
中科院分区：
文献类型：
--
作者：
Meyer, S;Richtering, W
聚（N-异丙基丙烯酰胺）（PNiPAM）的水性混合物越来越受到人们的关注，主要是因为它们在水中的温度敏感溶解度。 1, 2 当较低临界溶液温度约为 1, 2 时，线性 PNIPAM 大分子会表现出卷曲到球状的转变。接近32°C；宏观凝胶在加热时表现出强烈的收缩，并且发现了体积相变。胶体分散的 PNIPAM 微凝胶也观察到类似的行为，3 其流体动力学半径在高温下急剧减小。由于这种强烈的温度敏感性，已经讨论了这种 PNIPAM 微凝胶的几种应用。在大多数实验研究中，微凝胶颗粒的尺寸通过动态光散射来表征，尽管众所周知，静态光散射可以通过完整形状因子的分析提供更详细的信息（参见参考文献 4 和 5）。即使无法获得完整的形状因子，F 参数（即回转半径与流体动力学半径的比值）也可以提供有关颗粒结构的附加信息。 6
Aqueous mixtures of poly (N-isoproplyacrylamide)(PNiPAM) are of growing interest mainly due to their temperature-sensitive solubility in water. 1, 2 Linear PNIPAM macromolecules display a coil-to-globule transition when the lower critical solution temperature of ca. 32 C is approached; macroscopic gels display strong shrinking upon heating, and a volume phase transition is found. Similar behavior is observed with colloidally dispersed PNIPAM microgels, 3 the hydrodynamic radius of which decreases strongly at elevated temperatures. Because of this strong temperature sensitivity, several applications of such PNIPAM microgels have been discussed.In most experimental studies the size of microgel particles is characterized by means of dynamic light scattering albeit it is well-known that static light scattering can provide more detailed information via the analysis of the full form factor (see eg refs 4 and 5). Even if the full form factor is not accessible, the F parameter, which is the ratio of radius of gyration and hydrodynamic radius, gives additional information on the particle structure. 6