Silica nanoparticle-membrane interactions investigated by atomic force microscopy in an organic solvent

Ion-exchange membranes have been widely used not only in water but also in organic solvents for both scientific exploration and industrial applications. Atomic force microscopy (AFM) is a promising analytical technique to determine membrane functions in both water and organic solvents. Nevertheless, the use of organic solvents frequently causes significant contamination and mechanical drift in AFM imaging investigations. Additionally, the rapid evaporation of organic solvents imposes the limitation of measurement time. Thus, a force curve array measurement requiring a longer time is challenging in organic solvents. Herein, we propose a widely adaptable holder design that facilitates stable AFM measurements in organic solvents for a broad range of AFM systems. Using the designed AFM holder, we investigated silica-membrane interactions in 2-propanol. Our AFM evaluation provides important information on nanoparticle removal with ion-exchange membranes in 2-propanol. The concept of widely adaptable holder design should contribute to the understanding of nanoparticle-membrane interactions and the development of various functional membranes used in organic solvents.