Gel-sol transition and thermotropic behavior of a chitosan derivative in lyotropic solution

“…Rout and coworkers [8][9][10] reported that N-phthalolyl chitosan, N-phthalolyl-3,6-di-O-acetyl chitosan, and N-phthalolyl-3,6-O-(butyl carbamate) chitosan had a lyotropic liquid-crystal property in dimethyl sulfoxide. The critical concentrations (C*'s; i.e., the lowest concentrations to form lyotropic liquid crystals) of these polymers were 0.25-0.27, 0.1, and 0.5%, respectively.…”

Section: Introductionmentioning

confidence: 99%

Liquid‐crystalline behavior of chitosan in malic acid

Chang

Tsai

2007

J of Applied Polymer Sci

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This report describes how the degree of deacetylation and molecular weight of chitosan and the concentrations of sodium chloride and malic acid affect the formation of lyotropic chitosan liquid crystals. Chitosan samples of various degrees of deacetylation were prepared from b-chitin that was isolated from squid pens. They were degraded by ultrasonic irradiation to various molecular weights. The critical concentrations forming chitosan liquid crystals were determined with a polarized microscope. A chitosan sample with a degree of deacetylation of 67.2-83.6% formed cholesteric lyotropic liquid crystals when it was dissolved in 0.37-2.59M malic acid. The critical concentrations increased with increasing degrees of deacetylation of chitosan. They decreased with increasing molecular weights or increasing concentrations of sodium chloride and malic acid.

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“…6 Rout and colleagues found cholesteric solutions in N-phthalolyl chitosan and N-phthaloyl-3,6-di-Oacetyl chitosan dissolved in organic solvents. [7][8][9] Ratto et al investigated the mesophase of water/ chitosan systems with differential scanning calorimetry. 10 Dong and colleagues demonstrated the lyotropic liquid crystallinity of some chitosan derivatives and studied structure factors such as molar mass and degree of substitution on critical concentration (C*) forming the liquid-crystal phase.…”

Section: Introductionmentioning

confidence: 99%

Influence of degree of deacetylation on critical concentration of chitosan/dichloroacetic acid liquid‐crystalline solution

Dong

Wang

et al. 2001

J of Applied Polymer Sci

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We prepared chitosans with various degrees of deacetylation (DDAs) by mixing completely deacetylated chitosan and acetic anhydride at room temperature without serious degradation and O-substitution. We obtained a standard curve to measure DDA by plotting the IR absorbance ratio of A(1560)/A(2880) against the known DDAs (from 1-100%) of 10 specimens. The effect of DDA on the critical concentration (C*) of chitosan/dichloroacetic acid solutions required to form mesophase was investigated by optical methods. A maximum C* value of 23 wt % appeared at a relative medium DDA (similar to 20%). The effect was explained by the disordering of chains with medium composition ratios of the copolymer of glucosamine and N-acetyl glucosamine. (C) 2002 John Wiley & Sons, Inc. J Appl Polym Sci 83: 1204-1208, 2002

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Gel-sol transition and thermotropic behavior of a chitosan derivative in lyotropic solution

Cited by 38 publications

References 3 publications

Polyelectrolyte complex materials from chitosan and gellan gum

Polyelectrolyte complex materials from chitosan and gellan gum

Liquid‐crystalline behavior of chitosan in malic acid

Influence of degree of deacetylation on critical concentration of chitosan/dichloroacetic acid liquid‐crystalline solution

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