Rheological characterization of CNC-CTAB network below and above critical micelle concentration (CMC)

Carbohydr Polym. 2021 Apr 1:257:117552. doi: 10.1016/j.carbpol.2020.117552. Epub 2021 Jan 12.

Abstract

The network of Cellulose Nanocrystal (CNC) suspension is explored below and above the critical micelle concentration (CMC), in the presence of cetyltrimethylammonium bromide (CTAB) with a positively charged head using TEM imaging and rheological characterization. CNC-CTAB gels show shear thinning behavior, complex relationship between strain amplitudes and CTAB concentration, diminishing thixotropic behavior as a function of CTAB and single and two yielding stress maxima as a function of CTAB, resulting from different microstructure below and above the critical Micelle Concentration (CMC) of CTAB. Comparing the flow curves of CNC-CTAB suspension/gel revealed the role played by CTAB content, CNC concentration and sonication energy in strengthening of the network. We analyzed and obtained yield stress from steady shear, creep testing and oscillatory experiments and compared them.

Keywords: Cellulose nanocrystals; Cetyltrimethylammonium bromide; Hydrogel; Micelle charge; Rheology; Sodium dodecyl sulfate; Thixotropic gel.