Journal ArticleDOI
Kinetics of swelling of gels
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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
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Journal ArticleDOI
Motion induced by asymmetric enzymatic degradation of hydrogels
Jennifer H. Hou,Adam E. Cohen +1 more
TL;DR: It is proposed that asymmetric degradation leads to asymmetric swelling, which transports particles up the enzyme concentration gradient, as functions of enzyme and gel concentrations.
Book ChapterDOI
Compression Effects on Cartilage Permeability
TL;DR: The general acceptance that the principal deformational character of articular cartilage is viscoelastic is accepted, but Sokoloff and co-workers showed that after removal of the load complete recovery of the tissue is obtained only if it is submerged in a bath of fluid.
Journal ArticleDOI
Stimuli-responsive microgels with cationic moieties: characterization and interaction with E. coli cells.
Larissa Hussmann,Larissa Hussmann,Thomke Belthle,Thomke Belthle,Dan E. Demco,Dan E. Demco,Radu Fechete,Andrij Pich,Andrij Pich,Andrij Pich +9 more
TL;DR: In this paper, the authors synthesize poly(N-vinylcaprolactam-co-1,vinyl-3-methylimidazolium) (poly(VCL-VIM+)) microgels carrying permanent positive charges and demonstrate that 1H high-resolution NMR spectroscopy in combination with transverse (T2) magnetization relaxometry allows investigating separately the behavior of each functional group in the microgel network.
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Insulin delivery using dynamic covalent boronic acid/ester‐controlled release
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Journal ArticleDOI
Swelling Dynamics of a Disk-Shaped Gel
Xingkun Man,Masao Doi +1 more
Abstract: When a gel absorbs solvent from surrounding, stress field is created in the gel, and this causes complex dynamics of the swelling behavior. Here we study this effect for disk-shaped gel by rigorously solving the diffusio-mechanical coupling equation. We show that (a) while the macroscopic thickness and the radius of the gel increases monotonically in time, the gel is compressed near the mid-plane, and that (b) while the swelling time depends on the shear modulus $G$ of the gel, its dependence is weak, and the time is mainly determined by the friction constant of the gel network and the osmotic bulk modulus of the gel. We also show that these characteristic features are reproduced accurately by a simple variational calculation for the gel deformation. An analytical expression is given for the swelling time.
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