Effect of cellulose nanocrystals in a cellulosic liquid crystal behaviour under low shear (regime I): Structure and molecular dynamics

In the field of cellulosic liquid crystals, attempts to establish the relationship between structure/properties have been developed. Above a critical concentration in an aqueous solution, hydroxypropylcellulose self-assembles in order to form cholesteric liquid crystal phases (LC-HPC). In this work we aim to understand how the incorporation of a low content of cellulose nanocrystals (CNC) within LC-HPC/H2O (50 wt%), could influence the behaviour of the system when subjected to low shear rates, where the cholesteric phase still persists. The analysis of the deuterium spectrum and the T-2 (transversal relaxation) values confirm that the mobility of LC-HPC at low shear rates is restricted due to CNC, and consequently so is the flow of the cholesteric polydomains. These effects are more evident in the some sample containing 2 wt% of CNC; besides needing more strain units to induce some degree of order, the achieved degree of order is recovered faster when compared to the reference sample. (C) 2016 Elsevier Ltd. All rights reserved.