Max Planck Institute of Colloids and Interfaces, 14424, Potsdam, Germany.
Macromol Rapid Commun. 2013 Oct;34(20):1629-34. doi: 10.1002/marc.201300517. Epub 2013 Sep 11.
A new class of colloidal polymeric particles consisting of polystyrene spheres grown in a poly(N-isopropyl acrylamide) precursor scaffold is synthesized via redox-initiated heterophase polymerization. The morphology and thermoresponsiveness of these assemblies is proven by electron microscopy investigations and temperature-dependent measurements of the change of both the speed of sound travelling through the dispersion and the hydrodynamic particle size. Electron microscopy (EM) micrographs (transmission and scanning EM as well cryo-scanning EM) prove the existence of colloidal clusters when the freeze-dried copolymer is redispersed in pure water. The clusters have a size of several micrometers, contain about 800 polystyrene particles with diameter below 100 nm, and show a highly reproducible thermoresponsive behavior with a lower critical solution temperature corresponding to that of pure poly(N-isopropyl acrylamide).
通过氧化还原引发的多相聚合，合成了一类由聚苯乙烯球在聚（N-异丙基丙烯酰胺）前体支架中生长而成的新型胶体聚合物粒子。通过电子显微镜研究和分散体中声速传播速度以及水动力粒径随温度变化的温度依赖性测量，证明了这些组装体的形态和温敏性。电子显微镜（EM）显微照片（透射和扫描 EM 以及冷冻扫描 EM）证明了当冻干共聚物在纯水中重新分散时存在胶体簇。这些簇的尺寸为数微米，包含约 800 个直径小于 100nm 的聚苯乙烯颗粒，并且表现出高度可重现的温敏行为，其下临界溶液温度对应于纯聚（N-异丙基丙烯酰胺）的下临界溶液温度。
