Polymer gel application

Ross-Murphy, SB, Physical Gelation of Synthetic and Biological Macromolecules. In Polymer Gels, Fundamentals and Biomedical Applications DeRossi, D Kajiwara, K Osada, Y Yamauchi, A, eds. Plenum Press New York, 1991 21. 

Polymer gels In response to pH changes in their enviromnent, materials derived from poly(acrylonitrile) will swell or shrink in a slow analogy to muscle action, thought to have robotic applications. 

From the experimental results, the ER effect in polymer gels is explained as follows (Fig. 8). When an electric field is applied, the particles electrically bind together and cannot slip past each other. Larger shear forces are needed in the presence of an electric field. Thus, the electric field apparently enhances the elastic modulus of the composite gel. The difference in ER effects between an oil and a gel is that the polarized particles necessarily cannot move between the electrodes to produce the ER effect in a gel. In order for the ER effect to occur, it is important to form migration paths before application of an electric field. 

Fig. 8. Schematic illustration of the ER effect in a polymer gel. The paths of the particles have been formed before application of an electric field...

Kokufuta, E. Novel Applications for Stimulus-Sensitive Polymer Gels in the Preparation of Functional Immobilized Biocatalysts. Vol. 110, pp. 157-178. 

De Rossi D, Kajiwara K, Osada Y, Yamauchi A (eds) (1991) Polymer gels fundamental and biomedical applications. Plenum, New York... 

Reports of building up two-dimensional polymers have been published by several research groups [9-12]. Additional reports [13-15] and a review [16] have appeared on stimuli-responsive polymer gels and their application to chemomechanical systems. The preparation and application of new monosized polymer particles have been reviewed [17]. 

Polymer gels have found wide applications in various fields medicine, the nutritive and petrochemical industries, agriculture, biotechnology, etc. They are also used in scientific research for example, in the separation and extraction of natural macromolecules such as DNA and proteins. 

We note here that gel is a coherent solid because its structure is characterized by a polymer network, and hence, the above theoretical considerations on crystalline alloys should be applicable to gels without essential alteration. It is expected that the curious features of the first-order transition of NIPA gels will be explained within the concept of the coherent phase equilibrium if the proper calculation of the coherent energy and the elastic energy of the gel network is made. This may be one of the most interesting unsolved problems related to the phase transitions of gels. 

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