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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Journal ArticleDOI
Photografted temperature-sensitive poly(N-isopropylacrylamide) thin film with a superfast response rate and an interesting transparent–opaque–transparent change in its deswelling process
TL;DR: In this paper, the fabrication of temperature-sensitive poly(N-isopropylacrylamide) thin films by a UV-induced surface photografting method was reported.
Book ChapterDOI
Swelling-Related Processes in Hydrogels
TL;DR: In this paper, the authors introduce the Flory-Huggins theory and rubber elasticity theory for the fluid dynamics of hydrogels, and show that these theories can explain changes of the gel properties, mostly the dramatic change of their swollen volume, in response to specific environmental stimuli.
Journal ArticleDOI
Ultrafast Responsive Poly(N-isopropylacrylamide) Gel Produced by Cryostructuring of Self-crosslinkable Polymer Microgels
TL;DR: A macroporous structure composed of closely aggregated thermoresponsive particles which exhibit an ultrafast temperature response is prepared by cryo-structuration of N-isopropylacrylamide-co-N-hydroxymethylacylamide (NIPA- co-HMAm) particle suspensions.
Journal ArticleDOI
The Double-Faced Electrostatic Behavior of PNIPAm Microgels.
TL;DR: In this paper, the authors show that collapsed ionic PNIPAm microgels undergo large mobility reversal and reentrant condensation when they are co-suspended with oppositely charged polyelectrolytes (PE) or nanoparticles (NP), while their stability remains unaffected by PE or NP addition at lower temperatures, where microgel are swollen and their charge density is low.
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