Laboratoire de Physico-chimie des Polymères et Milieux Dispersés-Sciences et Ingénierie de la Matière Molle, UMR7615, UPMC Sorbonne Universités, ESPCI ParisTech, CNRS, 75231 Paris Cedex 05, France.
Langmuir. 2011 Oct 18;27(20):12329-35. doi: 10.1021/la2023852. Epub 2011 Sep 26.
Aggregation of thermosensitive polymer-coated gold nanoparticles was performed in aqueous solution in the presence of a triblock copolymer poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic P123, PEO(20)-PPO(68)-PEO(20)). The gold nanoparticles, AuNPs, which are covered by thermosensitive statistical copolymers poly(EO(x)-st-PO(y)), aggregate when the temperature is higher than the phase transition temperature of the polymer, leading to a macroscopic precipitation. The presence of Pluronic chains in solution prevents the uncontrolled aggregation of the AuNPs at higher temperature than both the aggregation temperature of the AuNPs (T(agg)) and the critical micellization temperature (cmt) of the Pluronic. The size, the colloidal stability, and the optical properties of the AuNPs aggregates are modulated as a function of the P123-to-AuNP ratio, which constitutes the critical parameter of the system. Moreover, the AuNP aggregation is totally reversible upon decreasing the temperature below T(agg). Our approach constitutes an easy way to the formation of well-controlled nanoparticle aggregates with well-defined sizes. The resulting aggregates have been characterized by UV-vis spectroscopy, dynamic light scattering, and electron microscopy.
在三嵌段共聚物聚（氧化乙烯）-嵌段-聚（氧化丙烯）-嵌段-聚（氧化乙烯）（Pluronic P123，PEO(20)-PPO(68)-PEO(20)）存在的情况下，在水溶液中进行了温敏聚合物包覆的金纳米粒子的聚集。金纳米粒子（AuNPs）被温敏统计共聚物聚（EO(x)-st-PO(y)）覆盖，当温度高于聚合物的相变温度时会聚集，导致宏观沉淀。溶液中存在的 Pluronic 链可防止 AuNPs 在高于 AuNPs 聚集温度（T(agg)）和 Pluronic 的临界胶束化温度（cmt）的温度下发生失控聚集。AuNPs 聚集体的大小、胶体稳定性和光学性质可通过 P123 与 AuNP 的比例来调节，这是该体系的关键参数。此外，当温度降低到低于 T(agg)时，AuNP 的聚集是完全可逆的。我们的方法为形成具有良好定义尺寸的可控纳米粒子聚集体提供了一种简单的途径。所得聚集体通过紫外可见光谱、动态光散射和电子显微镜进行了表征。
