Liquid Crystal Systems from Fibrillar Polysaccharides

Chitin-chitosan nanocomposite gels: reinforcement of chitosan hydrogels with rod-like chitin nanowhiskers

“…[7][8][9][10][11][12][13]15,16 The widths of these rod-like microcrystals, commonly referred to as nanocrystals or nanowhiskers, are similar to those of their original microfibrils, whereas their lengths are reduced to 100-200 nm for microfibrils obtained from higher plants, and 1-2 mm for those from tunicins and algaes. 6 The colloidal suspensions of nanowhiskers are typical liquid crystals, showing strong flow birefringence under polarized light 11 and spontaneous formation of chiral nematic 7,10,13 or nematic 8 ordering.…”

“…The widths are about 20 nm for cellulose microfibrils of tunicates and algaes, 5,6 5-10 nm for ramie and cotton, 7-9 2-4 nm for wood pulps 10,11 and about 5-10 nm for chitin microfibrils derived from shells of crabs or shrimps. 12,13 The microfibril cross-sections for bacterial cellulose are 10 Â 50 nm. 14 It is estimated that the lengths of all these microfibrils are at least several micrometers.…”

Cellulose Nanocrystals as Advanced "Green" Materials for Biological and Biomedical Engineering

“…The three-dimensional (3D) hierarchical structures of CNCs at various scales and their ability to integrate other functional materials make CNC-based products promising candidates for electrical, electrochemical, and optical devices (Zheng et al, 2013). The anisotropic rod-like morphology of CNCs promotes lyotropic liquid crystalline behavior, which can be modified through concentration modulations (Marchessault et al, 1959;Urena-Benavides et al, 2011;Lagerwall et al, 2014). Under certain concentration and conditions, CNC suspensions may be slowly evaporated, resulting in semi-translucent films with ordered chiral nematic liquid crystals.…”

Properties of Nanocrystalline Cellulose Obtained From Celluloses of Annual Plants

“…При использовании серной кислоты в результате гидролиза поверхностные гидроксиль-ные группы замещаются сульфогруппами, при этом отрицательный заряд поверхности стаби-лизирует водные дисперсии частиц НКЦ за счет электростатического отталкивания [8]. В 1959 г. Marchessault et al опубликовали сообщение о том, что дисперсии НКЦ, полученные сернокислотным гидролизом, образуют лиотропные жидко-кристаллические фазы [9]. В 1992 г. была установлена характерная для самоорганизации водных дисперсий НКЦ хиральная нематическая (холестерическая) фаза [8].…”