Abstract
Cellulose acetate samples with a range of degrees of substitution (DS) were prepared by deacetylation of cellulose acetate (DS = 2.5). Chiral nematic solutions of the samples were prepared in formic acid. A handedness reversal from left to right was observed as the DS used to prepare the mesophase increased from 1.8 to 2.4. By selection of a suitably long-pitch mesophase, chiral nematic films cast from a CA (DS = 2.2)/formic acid solution showed a feint reflection of circularly polarized blue light. Deacetylation of this CA film gave a chiral nematic cellulose film with a more intense reflection band at the same wavelength. The improvement in intensity is attributed to the higher intrinsic birefringence of cellulose compared to cellulose acetate.
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Shimamoto, S., Gray, D.G. Chiral Nematic Cellulose Acetate Films; Reflectivity and Effect of Deacetylation. Cellulose 6, 15–22 (1999). https://doi.org/10.1023/A:1009248329779
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DOI: https://doi.org/10.1023/A:1009248329779