Posel Zbyšek, Posocco Paola, Lísal Martin, Fermeglia Maurizio, Pricl Sabrina
Department of Informatics, Faculty of Science, J. E. Purkinje University, Ústí nad Labem, Czech Republic and Laboratory of Physics and Chemistry of Aerosols, Institute of Chemical Process Fundamentals of the CAS, v. v. i., Prague, Czech Republic.
Molecular Simulations Engineering (MOSE) Laboratory, Department of Engineering and Architecture (DEA), University of Trieste, via Valerio 10, 34127 Trieste, Italy and National Interuniversity Consortium for Material Science and Technology (INSTM), Research Unit MOSE-DEA, University of Trieste, Italy.
Soft Matter. 2016 Apr 21;12(15):3600-11. doi: 10.1039/c5sm02867a.
In this work, the structural features of spherical gold nanoparticles (NPs) decorated with highly grafted poly(styrene) (PS), poly(vinylpyridine) (PVP) and PS-PVP diblock copolymer brushes immersed in a good solvent are investigated by means of Dissipative Particle Dynamics (DPD) simulations as a function of grafted chain length and of homopolymer and copolymer chain composition. For NPs grafted either by PS or PVP homopolymer brushes (selected as a proof of concept), good agreement between the Daoud-Cotton theory, experimental evidence, and our DPD simulations is observed in the scaling behavior of single chain properties, especially for longer grafted chains, and in brush thickness prediction. On the other hand, for grafted chain lengths comparable to NP dimensions parabolic-like profiles of the end-monomer distributions are obtained. Furthermore, a region of high concentration of polymer segments is observed in the monomer density distribution for long homopolymers. In the case of copolymer-decorated NPs, the repulsion between PS and PVP blocks is found to substantially influence the radius of gyration and the shape of the end-monomer distribution of the relevant polymer shell. Moreover, for diblock chains, the un-swollen region is observed to be thinner (and, correspondingly, the swollen layer thicker) than that of a NP modified with a homopolymer of the same length. Finally, the lateral segregation of PS and PVP blocks is evidenced by our calculations and a detailed analysis of the corona behavior is reported, thus revealing the key parameters in controlling the surface properties and the response of diblock copolymer modified nanoparticles.
在本工作中，通过耗散粒子动力学（DPD）模拟研究了浸没在良溶剂中的、接枝有高度支化的聚（苯乙烯）（PS）、聚（乙烯基吡啶）（PVP）和PS - PVP二嵌段共聚物刷的球形金纳米粒子（NPs）的结构特征，考察了其作为接枝链长度以及均聚物和共聚物链组成的函数关系。对于通过PS或PVP均聚物刷接枝的纳米粒子（作为概念验证进行选择），在单链性质的标度行为方面，尤其是对于较长的接枝链，以及在刷厚度预测方面，观察到达乌德 - 科顿理论、实验证据和我们的DPD模拟之间具有良好的一致性。另一方面，对于与纳米粒子尺寸相当的接枝链长度，获得了端基单体分布的抛物线状轮廓。此外，对于长均聚物，在单体密度分布中观察到聚合物链段的高浓度区域。在共聚物修饰的纳米粒子的情况下，发现PS和PVP嵌段之间的排斥力对相关聚合物壳层的回转半径和端基单体分布形状有显著影响。此外，对于二嵌段链，观察到未溶胀区域比用相同长度的均聚物修饰的纳米粒子的未溶胀区域更薄（相应地，溶胀层更厚）。最后，我们的计算证明了PS和PVP嵌段的横向偏析，并报告了对冠层行为的详细分析，从而揭示了控制二嵌段共聚物修饰纳米粒子的表面性质和响应的关键参数。
