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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Energy Consumption for the Desalination of Salt Water Using Polyelectrolyte Hydrogels as the Separation Agent
Lukas Arens,Julius B. Albrecht,Johannes Höpfner,Karin Schlag,Axel Habicht,Sebastian Seiffert,Manfred Wilhelm +6 more
TL;DR: In this article, the authors used self-synthesized and commercial poly(acrylic acid) hydrogels to study the desalination performance in reference to sodium chloride solutions within the concentration range of 0.1-35 g L−1.
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Artificial sensing skin mimicking mechanoelectrical conversion properties of human dermis
TL;DR: Intrinsic mechanoelectrical conversion properties of skin tissues are investigated, and their origin is suggested to originate primarily from electrokinetic phenomena ( streaming potentials) operating in the dermis.
Journal ArticleDOI
Swelling Dynamics of a Gel Undergoing Volume Transition.
Tsutomu Tomari,Masao Doi +1 more
TL;DR: In this paper, the authors studied the swelling dynamics of a gel undergoing the volume transition and showed that the characteristic time of the swelling is proportional to L 2 0 ζ/ |σ c | (L 0, ζ and σ c being the gel size, the friction constant and the transition stress respectively), which diverges at the equilibrium transition temperature and that the volume of the gel increases in proportion to ''sqrt{t}'' until it reaches the final volume.
Journal ArticleDOI
Theory and numerical calculation of pattern formation in shrinking gels
TL;DR: In this article, a Ginzburg-Landau theory is given for pattern formation in 3D gels with cylindrical shapes during their shrinking such as volume phase transition, and patterns are classified according to anisotropy and the incompressibility of gels by the linearized stability analysis of the theory.
Journal ArticleDOI
Enzymatically degradable and pH‐sensitive hydrogels for colon‐targeted oral drug delivery. I. Synthesis and characterization
S. K. Bajpai,Sutanjay Saxena +1 more
TL;DR: The gels exhibited minimum swelling in an acidic pH medium through the formation of a complex hydrogen-bonded structure and underwent enzymatic degradation in a medium of pH 7.4 (i.e., simulating intestinal fluid) along with chain-relaxation-controlled swelling, and have potential for colon-targeted drug delivery.
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