Dynamics of Gels

Then we address the dynamics of diblock copolymer melts. There we discuss the single chain dynamics, the collective dynamics as well as the dynamics of the interfaces in microphase separated systems. The next degree of complication is reached when we discuss the dynamic of gels (Chap. 6.3) and that of polymer aggregates like micelles or polymers with complex architecture such as stars and dendrimers. Chapter 6.5 addresses the first measurements on a rubbery electrolyte. Some new results on polymer solutions are discussed in Chap. 6.6 with particular emphasis on theta solvents and hydrodynamic screening. Chapter 6.7 finally addresses experiments that have been performed on biological macromolecules. 

In Sect. 2, we briefly review the thermodynamics of the volume phase transition. In Sect. 3, the dynamics of gels are discussed and the theory of dynamic light scattering (DLS) is reviewed. Section 4 describes the current knowledge of the microscopic gel structure as shown by small-angle neutron... 

Tanaka, Hocker, and Benedek first realized this essential nature of gds and developed a theory of the dynamics of gel networks [16]. According to their theory the quasi-elastic light scattering from gel networks became one of the standard methods of studying polymer gels. Here we briefly outline the theory of the dynamics of gels. 

E. Molecular Dynamics of Gel Network and Gelation Mechanism To characterize the molecular dynamics of a polymer-chain in the gel state, relaxation parameters such as the spin-lattice relaxation times, nuclear Overhauser enhancements and linewidths were compared among the gel state, solution state of the random-coil form for higher alkaline conditions and lower molecular weight fractions... 

This chapter was adapted from in part, by permission, M. Otake, M. Inaba and H. Inoue, Kinematics of Gel Robots made of Electro-Active Polymer PAMPS Gel , Proceedings of IEEE International Conference on Robotics and Automation, pp.488-493, 2000 M. Otake, Y. Kagami, M. Inaba, and H. Inoue, Dynamics of Gel Robots made of Electro-Active Polymer Gel , Proceedings of IEEE International Conference on Robotics and Automation, pp. 1458-1462, 2001 M. Otake, Y. Nakamura, and H. Inoue, Pattern Formation Theory for Electroactive Polymer Gel Robots , Proceedings of IEEE International Conference on Robotics and Automation, pp.2782-2787, 2004. 

The formation of ordered two- and three-dimensional microstructuies in dispersions and in liquid systems has an influence on a broad range of products and processes. For example, microcapsules, vesicles, and liposomes can be used for controlled drug dehvery, for the contaimnent of inks and adhesives, and for the isolation of toxic wastes. In addition, surfactants continue to be important for enhanced oil recovery, ore beneficiation, and lubrication. Ceramic processing and sol-gel techniques for the fabrication of amorphous or ordered materials with special properties involve a rich variety of colloidal phenomena, ranging from the production of monodispersed particles with controlled surface chemistry to the thermodynamics and dynamics of formation of aggregates and microciystallites. 

Solutions of surfactant-stabilized nanogels share both the advantage of gels (drastic reduction of molecular diffusion and of internal dynamics of solubilizates entrapped in the micellar aggregates) and of nonviscous liquids (nanogel-containing reversed micelles diffuse and are dispersed in a macroscopicaUy nonviscous medium). Effects on the lifetime of excited species and on the catalytic activity and stability of immobilized enzymes can be expected. 

T Tomari, M Doi. Hysteresis and incubation in the dynamics of volume transition of spherical gels. Macromolecules 28 8334-8343, 1995. 

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