Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan.
Department of Applied Biological Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, 183-8509, Japan.
Chemistry. 2022 Sep 6;28(50):e202201560. doi: 10.1002/chem.202201560. Epub 2022 Aug 3.
Surface ligands are essential tools for the stabilization of colloidal nanoparticles (NPs) in solvents. However, knowledge regarding the effects of the ligand shell, especially the ligand length, is insufficient and controversial. Here we demonstrate solution-based experiments on n-alkylphosphonate-capped TiO NPs to investigate the effects of ligand length and solution temperature on colloidal stability. A robust ligand-exchange process is achieved that draws free ligands and impurities away from the colloidal solution. In the case of 8 nm anatase NPs in toluene, the dodecylphosphonate ligand provided better colloidal stability than all the other n-alkylphosphonate ligands. In addition, relaxation studies suggested there is kinetic hysteresis in the dispersion/agglomeration transition. The proposed method is applicable to a wide range of surface ligands designed to maximize the colloidal stability of NPs.
表面配体是稳定胶体纳米粒子（NPs）在溶剂中的重要工具。然而，关于配体壳，特别是配体长度的影响的知识还不够充分，并且存在争议。在这里，我们通过基于溶液的实验研究了正磷酸酯封端的 TiO2 NPs，以研究配体长度和溶液温度对胶体稳定性的影响。实现了一种强大的配体交换过程，将游离配体和杂质从胶体溶液中去除。在甲苯中的 8nm 锐钛矿 NPs 的情况下，十二烷基磷酸酯配体比所有其他正磷酸酯配体提供了更好的胶体稳定性。此外，弛豫研究表明在分散/聚集转变中有动力学滞后。所提出的方法适用于广泛的表面配体，旨在最大限度地提高 NPs 的胶体稳定性。
