SURFACE-STRUCTURE OF LATEX-PARTICLES COVERED WITH TEMPERATURE-SENSITIVE HYDROGEL LAYERS
SURFACE-STRUCTURE OF LATEX-PARTICLES COVERED WITH TEMPERATURE-SENSITIVE HYDROGEL LAYERS
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DOI：
10.1006/jcis.1994.1291
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发表时间：
1994-08-01
影响因子：
9.9
通讯作者：
OHSHIMA, H
中科院分区：
文献类型：
--
作者：
MAKINO, K;YAMAMOTO, S;OHSHIMA, H
测量了两种具有核壳结构的模型乳胶粒子的电泳迁移率和尺寸，并与无壳结构的乳胶粒子进行了比较。这些乳胶颗粒具有带负电的核心，覆盖有带负电或不带电的温度敏感聚（N-异丙基丙烯酰胺）水凝胶层。乳胶表面层的电荷密度和“柔软度”是从乳胶颗粒的电泳迁移率数据中获得的，显示出在聚（N-异丙基丙烯酰胺）相变温度（33℃）附近的突然变化。此外，这些变化与 33 摄氏度左右乳胶颗粒尺寸的变化相关。水凝胶层厚度对颗粒的温度依赖性解释了上述观察结果。带负电荷的聚（N-异丙基丙烯酰胺）表面凝胶层随着温度升高而收缩，导致聚（N-异丙基丙烯酰胺）链段在颗粒核心上积累。这使得粒子变得更硬。另一方面，不带电的聚(N-异丙基丙烯酰胺)表面凝胶层的厚度没有明显变化，但随着温度升高，聚合物链段的构型发生变化，使得表面层变得更软，这可能是因为聚合物链段的积累在表面层中产生了空隙空间。 (C) 1994 年学术出版社。公司
The electrophoretic mobility and the size of two types of model latex particles with a core-shell structure were measured and compared with those for latex particles with no shell structure. These latex particles have a negatively charged core, covered with negatively charged or uncharged temperature-sensitive poly(N-isopropylacrylamide) hydrogel layers. The charge density and the ''softness'' of the latex surface layer were obtained from the electrophoretic mobility data of the latex particles, showing a sudden change around the phase transition temperature (33-degrees-C) of poly(N-isopropylacrylamide). Also, these changes are correlated with a change in the size of the latex particles around 33-degrees-C. The temperature dependence of the hydrogel layer thickness on the particle accounts for the above observations. The negatively charged poly(N-isopropylacrylamide) surface gel layer shrinks as temperature increases, leading to an accumulation of the poly(N-isopropylacrylamide) segments on the particle core. This makes the particle harder. The uncharged poly(N-isopropylacrylamide) surface gel layer, on the other hand, does not change its thickness appreciably, but a change in configuration of the polymer segments occurs as the temperature increases, so that the surface layer becomes softer, probably because void spaces are created in the surface layer by the accumulation of polymer segments. (C) 1994 Academic Press. Inc.