Intrinsic viscosity of cellulose derivatives and the persistent cylinder model of Yamakawa

Dayan, Serkan; Maïssa, P.; Vellutini, M.J.; Sixou, P.

doi:10.1016/0032-3861(82)90137-9

Cited by 30 publications

(5 citation statements)

References 27 publications

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“…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: 99%

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: 99%

Local Conformation of the Cellulosic Chain in Solution

Yanai

Sato

2006

Polym J

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“…In the Yamakawa–Fujii model for wormlike chains, the intrinsic viscosity is a function of molecular weight, contour length, Kuhn length, and a constant dependent on the diameter and contour length of the chain . These equations may be applied to simultaneously solve for diameter and Kuhn length through iteration, which tends to underestimate their values. , Alternatively, the chain diameter has been approximated with eq or through X-ray diffraction measurements, such that the Kuhn length remained the only unknown parameter. , Bohdanecky’s technique builds upon the Yamakawa–Fujii method and involves plotting true( M 2 [ η ] true) 1 / 3 vs M , where M is the molecular weight in g/mol and [η] is the intrinsic viscosity in Pa·s, evaluating the linear slope between these variables, and converting this value into Kuhn length and diameter. ,,, Kuhn lengths calculated with the Bohdanecky plot generally agree well with those determined from the Yamakawa−Fujii treatment but the rod diameters obtained with Bohdanecky theory tend to have stronger agreements with experimentally determined values. , …”

Section: Cholesteric Solutions Of Cellulose Derivativesmentioning

confidence: 99%

“…Applying a theoretical framework such as the one we have outlined may also aid in explaining the observed trends of critical concentrations in chiral nematic cellulosic mesophases. For example, the idea that adding a larger substituent side group to the cellulose backbone would increase the chain diameter and alter the critical concentration was introduced while comparing cellulose tricarbanilate (CTC), cellulose nitrate (CN), and cellulose triacetate (CTA) and investigating cyanoethyl hydroxypropyl cellulose (CEHPC). , Yet, the impact of switching the side group on the persistence length remains largely unaddressed; the Kuhn length reported for CEHPC is nearly the same as that for HPC (286 and 274 Å, respectively), while this dimension increases in the order of CTA (114 Å), CTC (172 Å), and CN (312 Å), a pattern unrelated to the size, as pointed out by Dayan et al , Additionally, when comparing cellulose diacetate and triacetate, which differ only in their degree of substitution (DS), persistence length decreases for increasing the number of substituent groups, explained by the reduced ability to form hydrogen bonds which decreases chain rigidity . While there is no report for the critical concentrations of these derivatives in various solvent systems, we can predict how changes in diameter and Kuhn length would alter the critical concentration value computed by Flory’s equation.…”

Section: Cholesteric Solutions Of Cellulose Derivativesmentioning

confidence: 99%

“…60 These equations may be applied to simultaneously solve for diameter and Kuhn length through iteration, which tends to underestimate their values. 11,62 Alternatively, the chain diameter has been approximated with eq 2 or through X-ray diffraction measurements, such that the Kuhn length remained the only unknown parameter. ( )…”

Section: ■ Introductionmentioning

confidence: 99%

“…10,62 Yet, the impact of switching the side group on the persistence length remains largely unaddressed; the Kuhn length reported for CEHPC is nearly the same as that for HPC (286 and 274 Å, respectively), while this dimension increases in the order of CTA (114 Å), CTC (172 Å), and CN (312 Å), a pattern unrelated to the size, as pointed out by Dayan et al 10,62 Additionally, when comparing cellulose diacetate and triacetate, which differ only in their degree of substitution (DS), persistence length decreases for increasing the number of substituent groups, explained by the reduced ability to form hydrogen bonds which decreases chain rigidity. 62 While there is no report for the critical concentrations of these derivatives in various solvent systems, we can predict how changes in diameter and Kuhn length would alter the critical concentration value computed by Flory's equation. Moreover, the framework we present may explain trends in the critical concentration using stiffness and bonding arguments, because of the connections between Kuhn length, intrinsic viscosity, and solubility.…”

Section: ■ Introductionmentioning

confidence: 99%

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Unraveling the Governing Mechanisms Behind the Chiral Nematic Self-Assembly of Cellulose-Based Polymers

Fine,

Chazot

2023

Chem. Mater.

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Thanks to their abundance and ability to selfassemble into photonic crystals that selectively reflect light, chiral nematic liquid crystalline cellulose polymers have been investigated as the basis for colorimetric sensors responsive to humidity, pressure, temperature, and other stimuli. In this perspective, we start by revisiting the early research on these materials to explain how different geometric and thermodynamic factors influence the self-assembly and optical properties of cholesteric phases constructed from cellulose derivatives. We explore how solubility, viscosity, and hydrogen bonding impact the onset of mesophase formation and the helicoidal arrangement. Having elucidated the controlling factors influencing the pitch−concentration relationship in these materials, we discuss efforts to preserve liquid crystalline order in solids and underscore the critical knowledge gaps in understanding how the kinetics of self-assembly affects both cholesteric order formation and retention.

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Order–Disorder conformation change of xanthan in 0.01M aqueous sodium chloride: Dimensional behavior

Liu

Norisuye

1988

Biopolymers

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SynopsisWeight-average molecular weights M,, second virial coefficients, and z-average radii of gyration (S2):/2 were determined by light scattering as a function of temperature T for four sodium salt samples of xanthan in 0.01M aqueous NaCI, in which the polysaccharide undergoes an order-disorder conformation change with increasing T. The data for (S2):/' and 44, at 25 and 80"C, the lowest and highest temperatures studied, confirmed the previous conclusion that the predominant conformation at the former T, i.e., in the ordered state, is a double helix, while that at the latter T, i.e., in the disordered state, is a dimerized coil expanded by electrostatic repulsions between charged groups of the polymer. As T was increased from 25 to W C , (SZ):/' sigmoidally decreased or increased depending on the dimer's molecular weight. This temperature dependence of (S2):/2 and that determined elsewhere for a high molecular weight sample were found to be described almost quantitatively by a simple dimer model in which the double helix melts from both ends, when the double-helical fraction in the dimer at a given T estimated previously from optical rotation data was used.

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Intrinsic viscosity of cellulose derivatives and the persistent cylinder model of Yamakawa

Cited by 30 publications

References 27 publications

Local Conformation of the Cellulosic Chain in Solution

Local Conformation of the Cellulosic Chain in Solution

Unraveling the Governing Mechanisms Behind the Chiral Nematic Self-Assembly of Cellulose-Based Polymers

Order–Disorder conformation change of xanthan in 0.01M aqueous sodium chloride: Dimensional behavior

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