caa a22 4500 475763475 CHVBK 20180406123558.0 cr unu---uuuuu 170329e20000101xx s 000 0 eng 10.1007/s003960050003 doi (NATIONALLICENCE)springer-10.1007/s003960050003 Quasielastic light scattering study of chemically crosslinked gelatin solutions and gels [Elektronische Daten] [J. Sharma, H. B. Bohidar] Quasielastic light scattering measurements are reported for experiments performed on mixtures of gelatin and glutaraldehyde (GA) in the aqueous phase, where the gelatin concentration was fixed at 5 (w/v) and the GA concentration was varied from 1×10−5 to 1×10−3 (w/v). The dynamic structure factor, S(q,t), was deduced from the measured intensity autocorrelation function, g 2(τ), with appropriate allowance for heterodyning detection in the gel phase. The S(q,t) data could be fitted to S(q,t)=Aexp(−D f q 2 t)+Bexp(−t/τc)β, both in the sol (50 and 60 ∘C) and gel states (25 and 40 ∘C). The fast-mode diffusion coefficient, D f showed almost negligible dependence on the concentration of the crosslinker GA; however, the resultant mesh size, ξ, of the crosslinked network exhibited strong temperature dependence, ξ∼(0.5−χ)1/5exp(−A/RT) implying shrinkage of the network as the gel phase was approached. The slow-mode relaxation was characterized by the stretched exponential factor exp(−t/τc)β. β was found to be independent of GA concentration but strongly dependent on the temperature as β=β0+β1 T+β2 T 2. The slow-mode relaxation time, τc, exhibited a maximum GA concentration dependence in the gel phase and at a given temperature we found τc(c)=τ0+τ1 c+τ2 c 2. Our results agree with the predictions of the Zimm model in the gel case but differ significantly for the sol state. Springer-Verlag Berlin Heidelberg, 2000 Key words Quasielastic light scattering studies nationallicence Gelatin gels nationallicence Chemical crosslinking nationallicence Fast and slow modes nationallicence Sharma J. School of Physical Sciences Jawaharlal Nehru University New Delhi 110 067, India e-mail: bohidar@jnuniv.ernet.in, IN aut Bohidar H. B. School of Physical Sciences Jawaharlal Nehru University New Delhi 110 067, India e-mail: bohidar@jnuniv.ernet.in, IN aut https://doi.org/10.1007/s003960050003 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s003960050003 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Sharma J. School of Physical Sciences Jawaharlal Nehru University New Delhi 110 067, India e-mail: bohidar@jnuniv.ernet.in, IN aut NATIONALLICENCE 700 1- Bohidar H. B. School of Physical Sciences Jawaharlal Nehru University New Delhi 110 067, India e-mail: bohidar@jnuniv.ernet.in, IN aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer