Effect of Temperature on the Flexibility of Cellulose Tricarbanilate in Dioxane and Ethyl Acetate by Dielectric Measurements

Gupta, A. K.; Marchal, E.; Burchard, Walther

doi:10.1021/ma60048a028

Cited by 44 publications

(25 citation statements)

References 3 publications

(4 reference statements)

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“…The temperature dependencies of [] are monotonous in THF, which are in a contrast with sigmoidal temperature dependencies of the dielectric relaxation frequency reported for CTC in dioxane. 22 The chain expansion of CTC with decreasing temperature was reported by several workers. [22][23][24][25][26] The values of k 0 are normal, indicating no aggregation of CTC in THF upon cooling.…”

Section: Resultsmentioning

confidence: 72%

“…22 The chain expansion of CTC with decreasing temperature was reported by several workers. [22][23][24][25][26] The values of k 0 are normal, indicating no aggregation of CTC in THF upon cooling. Figure 2 plots [] vs. M w double-logarithmically of CTC in THF at 0 and À25 C as well as the previous results at 25 C. 9 The molecular weight dependencies of [] become slightly stronger with lowering temperature.…”

Section: Resultsmentioning

confidence: 72%

“…references cited in ref 9). Figure 4 contains some literature data 10,22 for CTC in THF and dioxane by a diamond and triangles. Those results are not so much different from ours (filled and …”

Section: Resultsmentioning

confidence: 99%

“…Hsu et al assumed the cooperative ''stiff'' and ''flexible'' two state model from a sigmoidal temperature dependence of the dielectric relaxation frequency Local Conformation of the Cellulosic Chain in Solution in dioxane 22 and also an unusual molecular weight dependence of the radius of gyration in dioxane/methanol mixture 25 for CTC. As mentioned above, there are no such peculiar dependencies for CTC in THF that we do not have to introduce the cooperative two state model, at least for CTC in THF.…”

Section: Torsional Fluctuation In the Ctc Chainmentioning

confidence: 99%

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Local Conformation of the Cellulosic Chain in Solution

Yanai

Sato

2006

Polym J

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ABSTRACT:The temperature and molecular weight dependencies of the intrinsic viscosity [] were investigated for cellulose tris(phenyl carbamate) (CTC) in tetrahydrofuran (THF). By the analysis of the [] data in terms of the wormlike cylinder model, the persistence length q of CTC was determined as a function of the temperature. With decreasing the temperature from 25 to À20 C, q increases from 10.5 to 13.7 nm. This temperature dependence of q was successfully explained by the broken wormlike chain model, where each glucose residue in the cellulosic chain is assumed to take left-handed 3/1 or 2/1 helical state and occasionally a kink state generated by a glucosidic bridge angle fluctuation. While the torsional fluctuation in each glucosidic bond is considerably small, there are two energetically favored helical (3/1 and 2/1) states, so that the cellulosic chain may not be regarded as a regular helix in solution. [DOI 10.1295/polymj.38.226] KEY WORDS Cellulose Derivative / Intrinsic Viscosity / Persistence Length / Broken Wormlike Chain / Local Conformation / Helicity of polymer chains plays important roles in chain rigidity, liquid crystallinity, and chiral discrimination. Recently, several synthetic polymers have been found to take more or less regular helical conformations in solution, and extensive arguments have been made on the relationship among their chemical structure, helicity, chain rigidity, liquid crystallinity, and cholesteric structure. Many review articles deal with recent advances in this subject. [1][2][3][4][5] Cellulose derivatives are known as semiflexible polymers exhibiting liquid crystallinity 6,7 and important materials in chiral chromatography.8 These features imply helical nature in the cellulosic chain. Conformations of cellulose derivatives in solution were studied both experimentally and theoretically for a long time. However, as mentioned in a previous paper, 9 their conformational analysis was not an easy task because both chain stiffness and excluded volume effect must be taken into account simultaneously due to their intermediate chain rigidity. Only recent literature provides proper analyses for the conformation of cellulosic chains 9,10 and also for solution properties (e.g., liquid crystallinity, 11 viscosity, 12 and diffusivity 13 ) based on the properly analyzed conformation. On the other hand, theoretical studies on the conformation of the cellulosic chain were carried out by Brant et al.14-17 in 1970s, who made an extensive conformational energy analysis and found two energetically stable conformations implying left-handed 3/1 and 2/1 helices for the cellulosic chain. However, the characteristic ratio C 1 and its temperature dependence estimated from their conformational energy did not satisfactorily agree with experimental results for cellulose derivatives. 15,16 The disagreement was argued occasionally afterward, 17,18 but satisfactory explanation has not been made yet. Thus, the local conformation of the cellulosic chain is still unclear.In this study, we have revisited...

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Section: Resultsmentioning

confidence: 72%

Section: Resultsmentioning

confidence: 72%

Section: Resultsmentioning

confidence: 99%

Section: Torsional Fluctuation In the Ctc Chainmentioning

confidence: 99%

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Local Conformation of the Cellulosic Chain in Solution

Yanai

Sato

2006

Polym J

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“…Derivatives of cellulose are known to form cholesteric phases either in the melt or as highly concentrated solutions. After the description of the carbanilation reaction towards cellulose tricarbanilates (CTC), products of this reaction were examined regarding to persistence length and flexibility, the main characteristics to be capable of forming liquid crystalline phases. Liquid crystalline phases made of cellulose derivatives were examined intensively regarding to molecular and structural arrangement and with focus to molar mass, solvent compatibility, ternary mixtures as well as texture formation .…”

Section: Introductionmentioning

confidence: 99%

High Optical Quality Films of Liquid Crystalline Cellulose Derivatives in Acrylates

Wenzlik

Zentel

2013

Macro Chemistry & Physics

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Cholesteric liquid crystals based on polymers are attractive because of their film‐forming properties. However, their optical properties (sharpness and directionality of the selective reflection) are usually lower than low molar mass compounds because of a polydomain structure and an angular distribution of the helix axes. In this work, cholesteric films made of liquid crystalline cellulose derivatives with improved optical properties are prepared. The careful choice of the solvent, hydrogen bond influencing additives, the synthetic realization of a very high degree of substitution on the cellulosic polymer, and the use of mechanical stirring in combination with a tuned substrate treatment and film‐preparation method and subsequent polymerization allow the fabrication of free standing cholesteric films of high optical quality. They show selective reflection with a half width of only 25 nm and nearly only perpendicular reflection. In addition, a method is developed by which fluorescent dyes can be introduced into the films after their preparation.

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Conformational Properties of Polysaccharide Derivatives

Terao

Sato

2018

Bioinspired Materials Science and Engineering

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Effect of Temperature on the Flexibility of Cellulose Tricarbanilate in Dioxane and Ethyl Acetate by Dielectric Measurements

Cited by 44 publications

References 3 publications

Local Conformation of the Cellulosic Chain in Solution

Local Conformation of the Cellulosic Chain in Solution

High Optical Quality Films of Liquid Crystalline Cellulose Derivatives in Acrylates

Conformational Properties of Polysaccharide Derivatives

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