Effect of Graft Length and Matrix Molecular Weight on String Assembly of Aligned Nanoplates in a Lamellar Diblock Copolymer
Effect of Graft Length and Matrix Molecular Weight on String Assembly of Aligned Nanoplates in a Lamellar Diblock Copolymer
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DOI：
10.1021/acs.macromol.1c02478
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发表时间：
2022-04
期刊：
影响因子：
5.5
通讯作者：
Christian Tabedzki;Nadia M. Krook;C. Murray;R. Composto;Robert A. Riggleman
中科院分区：
文献类型：
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作者：
Christian Tabedzki;Nadia M. Krook;C. Murray;R. Composto;Robert A. Riggleman
接枝纳米颗粒聚合物复合材料已被用于创建高度定制的一类材料，其中球形纳米颗粒作为进入这类材料的门户设计。接枝的纳米片（纳米颗粒，其中半径比颗粒的高度长）提供了通过其各向异性特性来控制整体系统特性的机会和途径。目前关于应对与组装有关的挑战的研究相当有限，而且未经探索。使用混合粒子/自洽场理论（hSCFT）模拟，我们建立在我们以前的工作研究聚乙二醇（PEG）接枝纳米片内的近对称（f = 0.5）层状聚（苯乙烯-b-甲基丙烯酸甲酯）（PS-b-PMMA）嵌段共聚物（BCP）矩阵。我们研究了纳米片接枝长度和基质分子量之间的相互作用及其对平均力（PMF）势的影响。最终，我们发现，位置和深度的充满活力的井（局部最小值）和充满活力的障碍（局部最大值）的PMF，以及局部最大值的存在，是依赖于相对宽度的纳米片的层状域，与较长的移植物经历更深的充满活力的威尔斯井和进一步板间分离距离。结果是由界面张力驱动的，由于局部域膨胀效应所造成的插入到层状系统的纳米片。与实验分离距离的PEG接枝三氟化钆掺杂镱和铒，GdF 3：Yb/Er（20/2摩尔%）纳米片证实了在模拟中发现的相关性较大的矩阵域和扩大的能量阱。此外，平均间隔距离遵循与hSCFT数据类似的趋势。我们预计这些结果将有助于开发和设计BCP中的各向异性纳米颗粒，以创建针对特定应用和性能定制的纳米复合材料。
Grafted nanoparticle polymer composites have been used to create a highly bespoke class of materials, with spherical nanoparticles serving as the gateway design into this class. Grafted nanoplates (nanoparticles where the radius is longer than the height of the particle) provide opportunities and pathways to control overall system properties through their anisotropic properties. Current research on addressing the challenges associated with assembly is quite limited and unexplored. Using hybrid particle/self-consistent field theory (hSCFT) simulations, we build upon our previous work examining polyethylene glycol (PEG) grafted nanoplates within a nearly symmetric (f≈ 0.5) lamellar poly(styrene-b-methyl methacrylate) (PS-b-PMMA) block copolymer (BCP) matrix. We examine the interplay between the nanoplate graft length and matrix molecular weight and their effect on the potential of mean force (PMF). Ultimately, we discover that the location and depth of both the energetic well (local minimum) and the energetic barrier (local maxima) of the PMF, as well as the existence of the local maxima, are dependent on the relative width of the nanoplates to the lamellar domain, with the longer grafts experiencing deeper energetic wells and further interplate separation distances. The results are driven by the interfacial tension due to the local domain bulging effects caused by the insertion of the nanoplates into the lamellar system. With experimental separation distances of a PEG-grafted gadolinium trifluoride doped with ytterbium and erbium, GdF3:Yb/Er (20/2 mol %) nanoplates corroborate the correlation found in the simulations between larger matrix domains and a widening of the energetic well. Additionally, the average separation distance follows a trend similar to the hSCFT data. We anticipate these results to help in the development and design of anisotropic nanoparticles within BCPs to create nanocomposites tailored for specific applications and properties.