Impact of the Distributions of Core Size and Grafting Density on the Self-Assembly of Polymer Grafted Nanoparticles
Impact of the Distributions of Core Size and Grafting Density on the Self-Assembly of Polymer Grafted Nanoparticles
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DOI：
10.1021/acs.macromol.7b01093
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发表时间：
2017-10-10
期刊：
影响因子：
5.5
通讯作者：
Kumar, Sanat K.
中科院分区：
文献类型：
--
作者：
Bachhar, Nirmalya;Jiao, Yang;Kumar, Sanat K.
目前公认的是，当将亲水性纳米颗粒（NP）与聚合物链轻度接枝时，其在疏水性均聚物基质或小分子溶剂中自组装成各种超结构。目前，人们认为，一个给定的NP样品应该只组装成一种超结构取决于有利的NP核-核吸引力和接枝聚合物链之间的空间排斥力之间的相对平衡。令人惊讶的是，我们发现每个样品显示出多种NP组装体的同时形成，例如，分散良好的颗粒、线和聚集体。我们通过一个简单的几何模型，占NP核心大小的分布和每个NP上的接枝链的数量（这是特别重要的，在低覆盖率）的推广，使我们能够定量建模的聚集体形状分布。我们的结论是，在与明确定义的化学性质的分子表面活性剂相比，这些NP类似物的自组装是由这样的波动效应为主。
It is now well-accepted that hydrophilic nanoparticles (NPs) lightly grafted with polymer chains self-assemble into a variety of superstructures when placed in a hydrophobic homopolymer matrix or in a small molecule solvent. Currently, it is thought that a given NP sample should only assemble into one kind of superstructure depending on the relative balance between favorable NP core-core attractions and steric repulsion between grafted polymer chains. Surprisingly, we find that each sample shows the simultaneous formation of a variety of NP-assemblies, e.g., well-dispersed particles, strings, and aggregates. We show through the generalization of a simple geometric model that accounting for the distributions of the NP core size and the number of grafted chains on each NP (which is especially important at low coverages) allows us to quantitatively model the aggregate shape distribution. We conclude that, in contrast to molecular surfactants with well-defined chemistries, the self-assembly of these NP analogues is dominated by such fluctuation effects.