Journal ArticleDOI
Kinetics of swelling of gels
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TLDR
In this article, a theory of the kinetics of the swelling of polyacrylamide gels is presented, which is based on the assumption that the swelling time is determined by the diffusion coefficient of the fluid molecules.Abstract:
We present a theory of the kinetics of the swelling of a gel. The characteristic time of swelling is proportional to the square of a linear dimension of the gel and is also proportional to the diffusion coefficient of the gel network, which is defined as D=E/f where E is the longitudinal bulk modulus of the network, and f is the coefficient of friction between the network and the gel fluid. This constitutes an essential difference between the present theory and the previous theory which is based on the assumption that the swelling time is determined by the diffusion coefficient of the fluid molecules. Experimental data are shown for spheres of 5% polyacrylamide gels and are analyzed using the present theory. The value of the diffusion coefficient obtained from the macroscopic swelling experiments shows excellent agreement with that obtained microscopically using laser light scattering spectroscopy.read more
Citations
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Poroelastic swelling kinetics of thin hydrogel layers: comparison of theory and experiment
TL;DR: These experiments provide a simple route to completely characterize the material properties of the gel within the framework of linear poroelasticity, using only an optical microscope.
Journal ArticleDOI
A novel positively thermosensitive controlled-release microcapsule with membrane of nano-sized poly(N-isopropylacrylamide) gel dispersed in ethylcellulose matrix.
TL;DR: The present MC demonstrated a positively thermosensitive drug release and it was found that the present MC membrane made it possible to obtain an 'on-off' pulsatile release, which could alter the release rate in the order of a minute, in response to stepwise temperature changes between 30 and 50 degrees C.
Journal ArticleDOI
Controlling nanoparticle delivery in magnetic nanoparticle hyperthermia for cancer treatment: Experimental study in agarose gel
TL;DR: By adjusting the gel concentration and injection flow rate, the results have demonstrated that a relatively low injection rate leads to a spherically shaped nanofluid distribution in the gels which is desirable for controlling temperature elevations.
Journal ArticleDOI
Aging and drying of gels
TL;DR: In this paper, the chemical and physical processes occurring during the aging and drying of an inorganic gel are described, and several strategies are described that minimize the tendency of the gel to crack.
Journal ArticleDOI
Microgels and microcapsules in peptide and protein drug delivery.
TL;DR: Results from recent studies on factors affecting peptide/protein binding to, and release from, microgels and related systems are discussed, including effects of network properties, as well as protein aggregation, peptide length, hydrophobicity and charge (distributions), secondary structure, and cyclization.
References
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Journal ArticleDOI
Statistical-Mechanical Theory of Irreversible Processes : I. General Theory and Simple Applications to Magnetic and Conduction Problems
TL;DR: In this paper, a general type of fluctuation-dissipation theorem is discussed to show that the physical quantities such as complex susceptibility of magnetic or electric polarization and complex conductivity for electric conduction are rigorously expressed in terms of timefluctuation of dynamical variables associated with such irreversible processes.
Journal ArticleDOI
Spectrum of light scattered from a viscoelastic gel
TL;DR: In this paper, the spectrum of light scattered from thermally excited displacement fluctuations in polyacrylamide gels was measured using optical mixing spectroscopy, and the correlation function for the displacements having wave vector q is predicted for these gels to have the form of an exponential decay: exp(− Γt).
Journal ArticleDOI
An Introduction to the Theory of Elasticity
P. G. Appleby,R. J. Atkin,N. Fox +2 more