Aqueous counter collision using paired water jets as a novel means of preparing bio-nanofibers

•This shows a detailed investigation of the ACC technique as a rapid nano-decomposition process.•In ACC, aqueous suspensions are ejected from dual nozzles and collide at high speed and pressure.•ACC was capable of preparing cellulose nanofibers from wood, microbial and animal cellulose.•This work compared the ACC pulverization of stable Iβ-rich and meta-stable Iα-rich celluloses.•ACC is applicable not only to cellulose but to other polymeric materials. This study involved a detailed investigation of a novel approach to reducing naturally occurring cellulose fibers into nanofibers solely by the use of aqueous counter collision (ACC) without any chemical modification. In this process, equivalent aqueous suspensions of cellulose are ejected from dual nozzles and collide at high speed and pressure. Even a few repetitions of the collision process are sufficient to produce nano-sized fibers dispersed in water. This work compared the ACC nano-pulverization of stable Iβ-rich and meta-stable Iα-rich cellulose samples. The ACC method is applicable to various kinds of polymeric materials with hierarchical structures, either natural or synthetic, as a means of preparing aqueous dispersions of nano-sized structures.