Anomalous diffusion in aqueous solutions of gelatin

Ren, Shisong; Shi, Weiqing; Zhang, W. B.; Sorensen, C. M.

doi:10.1103/physreva.45.2416

Cited by 113 publications

(104 citation statements)

References 28 publications

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“…This crossover property is found also in other many-body relaxation systems besides glass-formers [7,[56][57][58][59][60][61][62], and hence it is a general property. The magnitude of t c depends on the intermolecular potential V (r ).…”

Section: Guides From Experimentsmentioning

confidence: 55%

Guides to solving the glass transition problem

Ngai¹,

Prevosto²,

Capaccioli³

et al. 2008

J. Phys.: Condens. Matter

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Relaxation in glass-forming substances is necessarily a many-body problem because of intermolecular interactions and constraints. Results from molecular dynamics simulations and experiments are used to reveal the critical elements and general effects originating from many-body relaxation, but not dealt with in conventional theories of the glass transition. Although many-body relaxation is still an unsolved problem in statistical mechanics, these critical elements and general effects will serve as guides to the construction of a satisfactory theory of the glass transition. This effort is aided by concepts drawn from the coupling model, whose predictions have been shown to be consistent with experimental facts.

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Section: Guides From Experimentsmentioning

confidence: 55%

Guides to solving the glass transition problem

Ngai¹,

Prevosto²,

Capaccioli³

et al. 2008

J. Phys.: Condens. Matter

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“…[21] The interpretation of the q dependence of m seems to be very controversial. Ren et al [27,28] reported such behavior for aqueous gelatin solutions and gels and made an interpretation in the context with anomalous diffusion. They discussed this behavior in terms of a and b relaxation in glasses.…”

Section: Resultsmentioning

confidence: 99%

Gelation Studies, 4

Richter¹,

Matzker²,

Schröter³

2005

Macromol. Rapid Commun.

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Summary: In a recent paper [S. Richter et al., Macromol. Rapid Commun. 2004, 25, 1504] the sol‐gel transition of two thermoreversible gelling mixtures made of xanthan gum and locust bean gum has been studied by using time‐resolved dynamic light scattering (DLS) and low‐amplitude oscillatory shear rheology, and is indicated by the presence of the typical power‐law behaviors in the time‐intensity correlation function g2(t) − 1 ∝ t−µ and in the oscillatory shear experiment G′(ω) ∝ G″(ω) ∝ ωn. A significant and reproducible difference of 7 K for the estimated gelation temperatures was found again, with the higher one always determined by rheology. We now present a logical explanation together with new results obtained on this system that may also be of importance for other ones. The incipient infinite percolated cluster that is formed during the gelation process is more pronounced, and is detectable earlier by rheology than by DLS for this present system.Double‐logarithmic plot of the time‐intensity correlation functions g2(t) − 1 versus the delay time t and at a scattering angle of θ = 90° and at several temperatures of the mixture.imageDouble‐logarithmic plot of the time‐intensity correlation functions g2(t) − 1 versus the delay time t and at a scattering angle of θ = 90° and at several temperatures of the mixture.

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“…The values of a s are somewhat higher (2.5-3) than that of the fast relaxation mode. This behavior is usually attributed [19,[36][37][38] to internal motions of large association complexes. In view of experimental errors of a f and a s , we argue that the photochemical scission of the polymer chains has no significant effect on either the q-dependence of the fast or the slow mode.…”

Section: Resultsmentioning

confidence: 99%

Characterization of Riboflavin‐Photosensitized Changes in Aqueous Solutions of Alginate by Dynamic Light Scattering

Kjøniksen

Baldursdóttir

Nyström

2004

Macromolecular Bioscience

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The effect of irradiation, in the wavelength range of 310-800 nm, on aqueous solutions (pH = 7.4) of alginate in the presence of the photosensitizer riboflavin (RF) has been investigated with the aid of dynamic light scattering (DLS). Under aerobic conditions light irradiation of RF causes scission of the polymer chains which affects the polymer dynamics. The time correlation data obtained from DLS experiments showed at all conditions the existence of two relaxation modes: one single exponential at short times, followed by a stretched exponential at longer times. The slow relaxation time revealed, over the whole considered concentration range, lower values for the alginate/RF system, whereas no effect of photochemical degradation was observed for the fast relaxation time in the semidilute regime. The results suggest that the photochemically induced fragmentation of alginate affects the slow relaxation mode, associated with disengagement relaxation of individual chains or cluster relaxation, in a similar way as the zero-shear viscosity. These findings provide detailed insight into the dynamics of the polymer matrix, and this knowledge can be useful in the context of controlled-release delivery of drugs. The chemical units of alginate (M = mannuronic acid and G = guluronic acid).

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Anomalous diffusion in aqueous solutions of gelatin

Cited by 113 publications

References 28 publications

Guides to solving the glass transition problem

Guides to solving the glass transition problem

Gelation Studies, 4

Characterization of Riboflavin‐Photosensitized Changes in Aqueous Solutions of Alginate by Dynamic Light Scattering

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