Paiva Felipe L, Hore Michael J A, Secchi Argimiro, Calado Verônica, Maia João, Khani Shaghayegh
Department of Macromolecular Science and Engineering, Case Western Reserve University, 2100 Adelbert Road, Cleveland, Ohio 44106, United States.
School of Chemistry, Universidade Federal do Rio de Janeiro, Rua Horácio Macedo 2030, Cidade Universitária, Rio de Janeiro, Rio de Janeiro 21941-909, Brazil.
Langmuir. 2020 Apr 21;36(15):4184-4193. doi: 10.1021/acs.langmuir.9b03604. Epub 2020 Apr 6.
Taking advantage of both shape and chemical anisotropy on the same nanoparticle offers rich self-assembly possibilities for nanotechnology. Through dissipative particle dynamics calculations, in the present work, the directed assembly of Janus nanorod aggregates and their capability to assemble into metastable novel structures at an interfacial level have been assessed. Symmetric Janus rods become kinetically trapped and exhibit either parallel or antiparallel alignment with respect to their long axis (different compositions). This depends on several factors that have been mapped herein and that can be precisely tuned: Flory-Huggins interaction parameter χ between polymer phases; concentration; shear rate; and even aggregate shape. Ultimately, two different aggregate structures result from rod tumbling that are not observed under quiescent conditions: monolayer-like aggregates exhibiting trapped rods with antiparallel configuration; and stacked nanorod arrays similar to superlattice sheets. These different structures can be controlled by the likelihood with which tumbling Janus rods encounter other aggregate portions showing parallel alignment. Hence, the present study offers fundamental insight into relevant parameters that govern the directed assembly of Janus nanoparticles at an interfacial level. Novel applications may potentially derive from the resulting aggregate structures, such as peculiar displays and sensors.
利用同一纳米颗粒上的形状和化学各向异性可为纳米技术提供丰富的自组装可能性。通过耗散粒子动力学计算，在本研究中，已评估了Janus纳米棒聚集体的定向组装及其在界面水平上组装成亚稳新结构的能力。对称Janus棒在动力学上被捕获，并相对于其长轴（不同组成）呈现平行或反平行排列。这取决于本文已确定且可精确调节的几个因素：聚合物相之间的弗洛里－哈金斯相互作用参数χ；浓度；剪切速率；甚至聚集体形状。最终，棒的翻滚产生了两种在静态条件下未观察到的不同聚集体结构：呈现反平行构型的捕获棒的单层状聚集体；以及类似于超晶格片的堆叠纳米棒阵列。这些不同的结构可通过翻滚的Janus棒与显示平行排列的其他聚集体部分相遇的可能性来控制。因此，本研究为控制Janus纳米颗粒在界面水平上定向组装的相关参数提供了基本见解。由此产生的聚集体结构可能会衍生出新颖的应用，例如特殊显示器和传感器。
