Chang Shery L Y, Reineck Philipp, Williams Dewight, Bryant Gary, Opletal George, El-Demrdash Samir A, Chiu Po-Lin, Ōsawa Eiji, Barnard Amanda S, Dwyer Christian
Eyring Materials Center, Arizona State University, Tempe, USA.
Nanoscale. 2020 Mar 7;12(9):5363-5367. doi: 10.1039/c9nr08984e. Epub 2020 Feb 26.
Nanodiamonds are increasingly used in many areas of science and technology, yet, their colloidal properties remain poorly understood. Here we use direct imaging as well as light and X-ray scattering reveal that purified detonation nanodiamond (DND) particles in an aqueous environment exhibit a self-assembled lace-like network, even without additional surface modification. Such behaviour is previously unknown and contradicts the current consensus that DND exists as mono-dispersed single particles. With the aid of mesoscale simulations, we show that the lace network is likely the result of competition between a short-ranged electrostatic attraction between faceted particles and a longer-ranged repulsion arising from the interaction between the surface functional groups and the surrounding water molecules which prevents complete flocculation. Our findings have significant implications for applications of DND where control of the aggregation behaviour is critical to performance.
纳米金刚石在许多科学技术领域的应用日益广泛，然而，其胶体性质仍未得到充分理解。在这里，我们通过直接成像以及光散射和X射线散射揭示，即使没有额外的表面修饰，水环境中的纯化爆轰纳米金刚石（DND）颗粒也会呈现出自组装的花边状网络。这种行为此前未知，并且与当前认为DND以单分散单颗粒形式存在的共识相矛盾。借助中尺度模拟，我们表明花边网络可能是多面体颗粒之间短程静电吸引力与表面官能团和周围水分子之间相互作用产生的长程排斥力之间竞争的结果，这种排斥力阻止了完全絮凝。我们的发现对于DND的应用具有重要意义，在这些应用中，聚集行为的控制对性能至关重要。
