Determination of tensile strength of microalgal cellulose microfibrils by cavitation-induced scission

Abstract

Nannochloropsis sp., among other microalgae, has a great potential to produce cellulose microfibril (CMF) due to their microscopic structure, fast growth on a large scale, abundant cellulose, and high crystallinity of a fiber, etc. In this work, in order to measure the tensile strength of a single microalgal fiber by cavitation-induced scission, cavitation kinetics for CMF was studied via atomic force microscope and Matlab program, Fiberapp. As a result, lower scission rate of CMF than that of carbon nanotube is explained experimentally using a variation of persistence length depending on the fiber length and sonication time. Moreover, for a reasonable estimation of tensile strength, fibers were investigated based on the limited conditions of fiber length and persistence length while the tensile strength of Nannochloropsis oceanica CMF was identified to be around 5 GPa. The obtained value is highly comparable with the tensile strength of multiwalled carbon nanotube synthesized by chemical vapor deposition and is higher than that of CMFs from other species.