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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Collapse-to-Swelling Transitions in pH- and Thermoresponsive Microgels in Aqueous Dispersions: The Thermodynamic Theory
TL;DR: In this article, the authors present a theory of a conformational collapse-to-swelling transition that occurs in aqueous dispersions of multiresponsive (pH- and thermoresponsive) microgels upon variation of ionic strength, temperature, or pH.
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Polyelectrolyte Multilayer Films for Building Energetic Walking Devices
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Characteristic Swelling–Deswelling of Polymer/Clay Nanocomposite Gels
TL;DR: Swelling behavior of nanocomposite hydrogels (NC gels) having organic polymer/inorganic clay network structures was systematically investigated, focusing on the role of exfoliated clay platelets with sodium counterions in the network and effects of various swelling conditions.
Journal ArticleDOI
Epoxy-based electroactive polymer gels
Yuka Yoshioka,Paul Calvert +1 more
TL;DR: In this paper, a new type of electroactive polymer gel is described, which is based on triepoxides cross-linked with polyfunctional amines, and the response time is in rough agreement with what would be expected for a diffusional process through a gel of this size (about 100 μm).
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Characterization of PNIPAAm photografted on PET and PS surfaces
Priscila Schroeder Curti,Márcia R. de Moura,Wanderley Veiga,Eduardo Radovanovic,Adley F. Rubira,Edvani C. Muniz +5 more
TL;DR: In this paper, virgin or oxidized films of PET and PS were submitted to surface modification by grafting of poly(N-isopropylacrylamide) or PNIPAAm.
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