Kim Young-Gon, Wagner Manfred, Thérien-Aubin Héloïse
Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany.
Macromolecules. 2020 Feb 11;53(3):844-851. doi: 10.1021/acs.macromol.9b01813. Epub 2020 Jan 28.
The design of surface-modified functional nanoparticles (NPs) is used to control the properties of the NPs and the NP/environment interactions. The efficient control of the final behavior of the NPs demands a comprehensive understanding of the resulting system. This is particularly challenging for systems with an architecture of the type polymer core-polymer canopy. In such systems, one of the key parameters influencing the behavior of the NPs is the local dynamics of the polymer canopy. However, because the grafting points of the canopy are experiencing their own local dynamics, predicting the final behavior of such systems is difficult. To get a deeper understanding of NPs made of a soft and swollen polymer core and a swollen polymer canopy, we prepared a library of hairy NPs made of a polystyrene (PS) core and a canopy of grafted poly(methyl acrylate) (PMA) chains. The softness of the PS core and the thickness of the PMA canopy were controlled, and the behavior and dynamics of the soft and hairy PS-PMA NPs in suspension were measured by H NMR relaxation and dynamic light scattering. It was observed that the rigid PS core slowed down the subsegmental dynamics of the PMA chains, while thick PMA canopies accelerated the relaxation of the PS core. The dynamics of the NPs in suspension was the result of the interplay between the PS core and the PMA canopy.
表面改性功能纳米粒子（NPs）的设计用于控制纳米粒子的性质以及纳米粒子与环境的相互作用。要有效控制纳米粒子的最终行为，需要全面了解所得系统。对于具有聚合物核-聚合物冠层结构类型的系统而言，这尤其具有挑战性。在这类系统中，影响纳米粒子行为的关键参数之一是聚合物冠层的局部动力学。然而，由于冠层的接枝点自身也存在局部动力学，因此预测此类系统的最终行为很困难。为了更深入地了解由柔软且溶胀的聚合物核和溶胀的聚合物冠层构成的纳米粒子，我们制备了一系列由聚苯乙烯（PS）核和接枝聚（甲基丙烯酸甲酯）（PMA）链冠层组成的多毛纳米粒子库。控制了PS核的柔软度和PMA冠层的厚度，并通过核磁共振弛豫和动态光散射测量了悬浮状态下柔软且多毛的PS-PMA纳米粒子的行为和动力学。观察到刚性的PS核减缓了PMA链的亚段动力学，而厚的PMA冠层加速了PS核的弛豫。悬浮状态下纳米粒子的动力学是PS核与PMA冠层之间相互作用的结果。
