Shear induced fluctuations and fluctuation-length transition in the quasiflexible polymer in a solution of a hydrogen-bond enhancing solvent
| Autor: | Hiroyuki Kawanishi, Yoshisuke Tsunashima |
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| Rok vydání: | 1999 |
| Předmět: | |
| Zdroj: | The Journal of Chemical Physics. 111:3294-3301 |
| ISSN: | 1089-7690 0021-9606 |
| DOI: | 10.1063/1.479664 |
| Popis: | Dynamics of cellulose diacetate (a typical polysaccharide) in N,N-dimethylacetamide (a hydrogen-bond enhancing solvent) at 27 °C was investigated in a shear field of velocity gradient γ=0–5.3 s−1 through dynamic light scattering under circular Couette flow. The polymer mass concentration was set around the crossover of dilute and semidilute regimes. Growth of extra-large length-scale fluctuations and their transitions with shear were detected, which were originated by the long-ranged interaction, or the hydrogen bond, operating on the OH and CO groups in the glucose residues of cellulose acetates via high electronegative solvent. Two modes of fluctuations with fast and slow decay rates Γf and Γs were induced and each Γ value changed stepwise and linearly with γ, respectively. The decay rate distribution, which was estimated from the electric-field time correlation function expressed in the KWW-type of stretched exponential decay form g(1)(t)=A exp[−(t/τ)β] with β the index of decay rate distributions, was... |
| Databáze: | OpenAIRE |
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