Nanoscale Porosity in Microellipsoids Cloaks Interparticle Capillary Attraction at Fluid Interfaces
Nanoscale Porosity in Microellipsoids Cloaks Interparticle Capillary Attraction at Fluid Interfaces
复制标题
微椭球体中的纳米级孔隙掩盖了流体界面处的颗粒间毛细管吸引力
DOI：
10.1021/acsnano.3c03301
复制
发表时间：
2023
期刊：
影响因子：
17.1
通讯作者：
Beltramo, Peter J.
中科院分区：
文献类型：
--
作者：
Trevenen, Samuel;Rahman, Md Anisur;Hamilton, Heather S. C.;Ribbe, Alexander E.;Bradley, Laura C.;Beltramo, Peter J.
钉扎在流体界面处的各向异性颗粒由于大的、取向依赖的毛细管力而倾向于无序的多颗粒配置，这是利用这些颗粒来创建功能性自组装材料的显著障碍。因此，目前的界面组装方法通常集中在各向同性球体上，其具有最小的毛细吸引力并且不依赖于界面平面中的取向。为了通过界面捕获的各向异性粒子产生具有复杂构型的长程有序结构，通过外部场和/或粒子工程控制粒子间相互作用能是必要的。在这里，我们合成胶体椭球与纳米级的孔隙度，并表明，它们的颗粒间的毛细吸引力在水-空气界面减少了一个数量级相比，他们的顺利同行。这是通过比较在水-空气界面处的光滑、粗糙和多孔椭球体的行为来实现的。通过监测两个粒子相互接近的动力学，我们表明多孔粒子表现出短程毛细相互作用势，其标度与描述光滑椭圆体行为的理论有着有趣的不同。此外，一个单一的颗粒周围的流体变形的干涉测量表明，多孔椭球体周围的界面不具有光滑椭球体的特征四极对称性，并定量地证实了毛细管相互作用能的减少。通过以这种方式设计纳米结构化的表面特征，可以控制颗粒之间的界面毛细相互作用，为由各向异性颗粒组成的复杂二维微结构的自组装提供了一种方法。
Anisotropic particles pinned at fluid interfaces tend toward disordered multiparticle configurations due to large, orientationally dependent, capillary forces, which is a significant barrier to exploiting these particles to create functional self-assembled materials. Therefore, current interfacial assembly methods typically focus on isotropic spheres, which have minimal capillary attraction and no dependence on orientation in the plane of the interface. In order to create long-range ordered structures with complex configurationsviainterfacially trapped anisotropic particles, control over the interparticle interaction energyviaexternal fields and/or particle engineering is necessary. Here, we synthesize colloidal ellipsoids with nanoscale porosity and show that their interparticle capillary attraction at a water–air interface is reduced by an order of magnitude compared to their smooth counterparts. This is accomplished by comparing the behavior of smooth, rough, and porous ellipsoids at a water–air interface. By monitoring the dynamics of two particles approaching one another, we show that the porous particles exhibit a much shorter-range capillary interaction potential, with scaling intriguingly different than theory describing the behavior of smooth ellipsoids. Further, interferometry measurements of the fluid deformation surrounding a single particle shows that the interface around porous ellipsoids does not possess the characteristic quadrupolar symmetry of smooth ellipsoids, and quantitatively confirms the decrease in capillary interaction energy. By engineering nanostructured surface features in this fashion, the interfacial capillary interactions between particles may be controlled, informing an approach for the self-assembly of complex two-dimensional microstructures composed of anisotropic particles.