Department of Chemical Engineering, University of Washington, Seattle, Washington 98195, United States.
Physical Science Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States.
J Phys Chem B. 2022 Jul 14;126(27):5117-5126. doi: 10.1021/acs.jpcb.2c02638. Epub 2022 Jun 28.
Shape-controlled colloidal nanocrystal syntheses often require facet-selective solution-phase chemical additives to regulate surface free energy, atom addition/migration fluxes, or particle attachment rates. Because of their highly tunable properties and robustness to a wide range of experimental conditions, peptoids represent a very promising class of next-generation functional additives for control over nanocrystal growth. However, understanding the origin of facet selectivity at the molecular level is critical to generalizing their design. Herein we employ molecular dynamics simulations and biased sampling methods and report stronger selectivity to Au(111) than to Au(100) for Nce3Ncp6, a peptoid that has been shown to assist the formation of 5-fold twinned Au nanostars. We find that facet selectivity is achieved through synergistic effects of both peptoid-surface and solvent-surface interactions. Moreover, the amphiphilic nature of Nce3Ncp6 together with the order of peptoid-peptoid and peptoid-surface binding energies, that is, peptoid-Au(100) < peptoid-peptoid < peptoid-Au(111), further amplifies its distinct collective behavior on different Au surfaces. Our studies provide a fundamental understanding of the molecular origin of facet-selective adsorption and highlight the possibility of future designs and uses of sequence-defined peptoids for predictive syntheses of nanocrystals with designed shapes and properties.
形状控制的胶体纳米晶体合成通常需要面选择性的溶液相化学添加剂来调节表面自由能、原子添加/迁移通量或颗粒附着速率。由于其高度可调的性质和对广泛实验条件的稳健性，肽代表了一类非常有前途的下一代功能添加剂，可用于控制纳米晶体的生长。然而，理解分子水平的面选择性的起源对于推广它们的设计至关重要。在此，我们采用分子动力学模拟和有偏采样方法，并报告了 Nce3Ncp6 对 Au(111)的选择性高于 Au(100)，Nce3Ncp6 已被证明有助于 5 重孪晶 Au 纳米星的形成。我们发现，面选择性是通过肽表面和溶剂表面相互作用的协同效应实现的。此外，Nce3Ncp6 的两亲性质以及肽-肽和肽-表面结合能的顺序，即肽-Au(100) < 肽-肽 < 肽-Au(111)，进一步增强了其在不同 Au 表面上的独特集体行为。我们的研究提供了对面选择性吸附的分子起源的基本理解，并强调了未来使用序列定义的肽设计和使用的可能性，以用于具有设计形状和性质的纳米晶体的预测合成。
