Assembly of Linked Nanocrystal Colloids by Reversible Covalent Bonds
Assembly of Linked Nanocrystal Colloids by Reversible Covalent Bonds
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DOI：
10.1021/acs.chemmater.0c04151
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发表时间：
2020-12-08
影响因子：
8.6
通讯作者：
Milliron, Delia J.
中科院分区：
文献类型：
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作者：
Dominguez, Manuel N.;Howard, Michael P.;Milliron, Delia J.
利用动态键合分子可逆地连接溶剂分散的纳米晶(NCS)是形成具有可控结构和宏观性质的胶体组装的一种很有前途的策略。在这项工作中，锡掺杂的氧化铟纳米管被功能化，配体与连接分子形成可逆的共价键，以驱动纳米管凝胶的组装。我们使用小角X射线散射来监测凝胶化过程，并表征了凝胶结构的变化如何影响由NCS的局域表面等离子体共振引起的红外光学性质。由于设计的连接化学，组装是可逆的，我们使用两种策略来拆解凝胶：添加多余的NCS来改变连接分子与NCS的比例，以及添加一个封端分子来取代连接分子。用热力学微扰理论计算了NC连接分子混合物的相图，使组装行为合理化。粗粒度分子动力学模拟揭示了环和桥连接基序之间的竞争，这对于理解NC凝胶是必不可少的。这项实验、计算和理论相结合的工作为控制和设计包含NC和溶剂组成的可逆胶体组件的性能提供了一个平台，这些组件与其他当代(例如，基于DNA)的连接策略兼容。
The use of dynamically bonded molecules designed to reversibly link solvent-dispersed nanocrystals (NCs) is a promising strategy to form colloidal assemblies with controlled structures and macroscopic properties. In this work, tin-doped indium oxide NCs are functionalized with ligands that form reversible covalent bonds with linking molecules to drive assembly of NC gels. We monitor the gelation by using small angle X-ray scattering and characterize how changes in the gel structure affect the infrared optical properties arising from the localized surface plasmon resonance of the NCs. The assembly is reversible because of the designed linking chemistry, and we disassemble the gels using two strategies: addition of excess NCs to change the ratio of linking molecules to NCs and addition of a capping molecule that displaces the linking molecules. The assembly behavior is rationalized using a thermodynamic perturbation theory to compute the phase diagram of the NC-linking molecule mixture. Coarse-grained molecular dynamics simulations reveal the competition between the loop and bridge linking motifs essential for understanding NC gelation. This combined experimental, computational, and theoretical work provides a platform for controlling and designing the properties of reversible colloidal assemblies that incorporate NC and solvent compositions beyond those compatible with other contemporary (e.g., DNA-based) linking strategies.