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
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Synthesis and characterization of poly(N‐vinyl imidazole) hydrogels crosslinked by gamma irradiation
Nursel Pekel,Olgun Güven +1 more
TL;DR: In this article, crosslinked poly(N-vinyl imidazole) (PVIm) hydrogels in the form of rods have been prepared by 60Co γ-radiation initiated simultaneous polymerization and crosslinking of Nvinyl IMIDazole in bulk and water.
Journal ArticleDOI
Responsive P(NIPAM-co-NtBAM) microgels: Flory–Rehner description of the swelling behaviour
TL;DR: In this article, a series of poly(N-isopropylacrylamide)(NIPAM) -poly(Ntert-butyl-acryamide) (NtBAM) copolymer microgels is prepared by surfactant-free emulsion polymerization using N,N′-methylenebis(acrylamide) (BIS) as crosslinker.
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Responsive hydrogels with poly(N-isopropylacrylamide-co-acrylic acid) colloidal spheres as building blocks
TL;DR: The proposed MCG hydrogels with improved thermo-responsive phase transition property are attractive for developing efficient stimuli-responsive smart sensors, actuators, bioseparation absorbants, and so on.
Journal ArticleDOI
Caterpillar-Inspired Design and Fabrication of A Self-Walking Actuator with Anisotropy, Gradient, and Instant Response.
TL;DR: A caterpillar-mimetic bilayer actuator is reported, based on a wrinkled polydimethylsiloxane elastomer decorated with a hydroresponsive polyelectrolyte brush, which can fold ultrafast into complex three-dimensional structures upon a change in relative humidity of the surrounding air.
Journal ArticleDOI
Fabrication and properties of thermosensitive organic/inorganic hybrid hydrogel thin films.
TL;DR: The thermoresponsive swelling-deswelling behavior and the viscoelastic properties of the hydrogel thin films were investigated as a function of temperature by using a quartz crystal microbalance (QCM) operated in water.
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