Cellulose nanocrystals with different morphologies and chiral properties

Publication date: 6 June 2018 Source:Polymer, Volume 145 Author(s): Volodymyr F. Korolovych, Vladyslav Cherpak, Dhriti Nepal, Amy Ng, Noor R. Shaikh, Anise Grant, Rui Xiong, Timothy J. Bunning, Vladimir V. Tsukruk The study reports the morphology and optical properties of a variety of cellulose nanocrystals (CNC) obtained from different natural sources with different dimensions and composition. A library of CNCs components with different dimensions, sulfate contents, and crystallite sizes was prepared under identical hydrolysis conditions from five distinct sources representing traditional choices ranging from soft and hard wood pulps to microcrystalline cellulose. High-resolution atomic force microscopy, scanning electron microscopy, scanning transmission electron microscopy, and X-ray diffraction confirmed that all CNCs have a well-defined needle-like morphology with different aspect ratios and axi-asymmetric cross-sections. Varying the cellulose sources resulted in wide variability of the CNC dimensions, including length (120–210 nm), aspect ratio (30–70), height (2.9–3.6 nm), and width (6–11 nm). Specifically, the CNCs from microcrystalline sources have large cross-sectional dimensions and produce straight CNC bundles, but CNCs from wood pulps have small cross-sections and form twisted bundles of a few individual nanocrystals. Chemical composition and surface potentials were found to be less critical to the resulting chiral characteristics and str...
Source: Polymer - Category: Chemistry Source Type: research