Visualizing the inside of three-dimensional self-organizing systems by three-dimensional atomic force microscopy

Abstract

Abstract The development of three-dimensional atomic force microscopy (3D-AFM) enabled the direct visualization of 3D hydration structures at solid–liquid interfaces with subnanometer resolution. Such imaging is possible because the hydration structure, once disorganized by the tip scan, can recover its original state through self-organization. Based on the same concept, the interior of any 3D self-organizing systems (3D-SOSs) may be visualized by 3D-AFM. To pursue this possibility, we have explored 3D-AFM imaging of various 3D-SOSs in interface sciences, life sciences and electrochemistry. Here, we review our recent progress in such 3D-AFM studies on 3D-SOSs, including hydration structures on cellulose nanocrystals, adsorption structures of anti-freezing surfactants on sapphire (0001) surfaces, intra-cellular components inside living cells, and charges accumulated inside an electric double layer. These examples demonstrate the effectiveness of 3D-AFM for understanding the nanoscale structures, properties and functions of various 3D-SOSs.