The Stirring-assisted Liquid Exfoliation of Hexagonal Boron Nitride and the Performance of h-BN/Cellulose Aerogel

Abstract

The delamination is the focus of two-dimensional layered materials' nano-crystallization. In this paper, two methods of stirring-assisted liquid exfoliation, DMF exfoliation and Hummers exfoliation, were utilized to prepare h-BN nanosheets. Microstructure, crystal structure and chemical structure were analyzed, which indicated that the h-BN nanosheets, with thickness of 1.4 nm and 5.4 nm respectively, were delaminated from bulk h-BN and their structure didn't show any obvious change, in accordance with the theoretical model. The interaction of oxygen in DMF and boron in h-BN weakened the "lip to lip"interaction between neighboring layers and then nanosheets were gained under violent stirring. Due to excellent corrosion resistance, bulk h-BN couldn't be exfoliated by strong oxidants. H+ protonated h-BN and only weakened slightly the "lip to lip"interaction. As a result, Hummers exfoliation wasn't doing well compared with DMF exfoliation. The h-BN/nano-fibillated cellulose aerogel had a very bag surface area and the air filled in these pores, which gave it the performance of thermal insulation and oil absorption.