Emergence of\nAmphiphilicity on Surfaces of Pure Cellulose\nNanofibrils Directly Generated by Aqueous Counter Collision Process

The present paper describes a downsizing mechanism of\nan aqueous\ncounter collision (ACC) process that enables the rapid preparation\nof cellulose nanofibrils (CNFs) as an aqueous dispersion solely by\nimpinging a pair of water jets containing the raw materials. Extensive\nstudies have revealed that the resulting CNFs by ACC have amphiphilic\nfiber surfaces, in which two kinds of faces with different natures\nare present along the entire fiber axis. They therefore have superior\nadsorption to surfaces of various conventional polymer plastics. These\ncharacteristic adsorption behaviors, which are totally different from\nthose for other CNFs prepared by other means, are attributable to\ntheir hydrophobic surfaces. In the present study, high-resolution\nmicroscopy, including atomic force microscopy, confocal laser scanning\nmicroscopy, and scanning electron microscopy with broad argon ion\nbeam milling, was used to determine how the emergence of such hydrophobic\ncharacteristics in a nanofibril face occurs in relation to the ACC\nnanopulverization mechanism due to the collision of the pair of water\njets.