Influence of Nonadditive Mixing on Colloidal Diamond Phase Formation from Patchy Particles
Influence of Nonadditive Mixing on Colloidal Diamond Phase Formation from Patchy Particles
复制标题
非加成混合对片状颗粒形成胶体金刚石相的影响
DOI：
10.1021/acs.jpcb.3c00708
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Escobedo, Fernando A.
中科院分区：
文献类型：
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作者：
Matos, Isabela Quintela;Escobedo, Fernando A.
纳米粒子(NPs)与杂化的嫁接DNA或DNA样链的混合物已被证明可以产生高度可调的NP-NP相互作用，如果设计成非加性混合，可能会导致更丰富的自组装行为。虽然非加性混合在分子流体中会导致非平凡的相行为，但它对胶体/NP材料的影响却很少被研究。在这里，通过对四面体片状NPs的二元系的分子模拟来探索这种效应，已知的四面体片状NPs自组装成钻石相。NPs是用隆起的斑块来模拟的，这些斑块通过代表嫁接链之间DNA杂交的粗粒间势相互作用。研究发现，在所研究的条件下，这些片状NPs自发成核成金刚石相，并且强相互作用的NP核消除了钻石相和体心立方相之间的竞争。我们的结果还表明，虽然较高的非加性对相行为的影响很小，但它在动力学上促进了金刚石相的形成。这种动力学增强被认为是由于相堆积密度的变化以及这些变化如何通过有利于各向同性相中的高密度基元和金刚石相中更大的NP振动来调制晶核的界面自由能。
Mixtures of nanoparticles (NPs) with hybridizing grafted DNA or DNA-like strands have been shown to create highly tunable NP–NP interactions, which, if designed to give nonadditive mixing, could lead to a richer self-assembly behavior. While nonadditive mixing is known to result in nontrivial phase behavior in molecular fluids, its effects on colloidal/NP materials have been much less studied. Such effects are explored here via molecular simulations for a binary system of tetrahedral patchy NPs, known to self-assemble into the diamond phase. The NPs are modeled with raised patches that interact through a coarse-grained interparticle potential representing DNA hybridization between grafted strands. It was found that these patchy NPs spontaneously nucleate into the diamond phase, and that hard-interacting NP cores eliminated the competition between the diamond and BCC phases at the conditions studied. Our results also showed that while higher nonadditivity had a small effect on phase behavior, it kinetically enhanced the formation of the diamond phase. Such a kinetic enhancement is argued to arise from changes in phase packing densities and how these modulate the interfacial free energy of the crystalline nucleus by favoring high-density motifs in the isotropic phase and larger NP vibrations in the diamond phase.