Dynamics of adsorbed polymers

Dynamics of adsorbed polymers", in New Trends in Physics and Physical Chemistry of Polymers. Ed. L.H. Lee, to be published by Plenum, New York, 1989. 

Structures and Dynamics of Adsorbed Polymer Nanolayers on Planar Solids... 

While the static aspects of the adsorption of single chains at walls have been studied for a long time [2], the dynamic properties of adsorbed polymers have received much less attention [30-32]. Most work considers the kinetics of either adsorption or desorption of polymers at a solid surface [31], or the... 

P. Y. Lai. Statics and dynamics of a polymer chain adsorbed on a surface Monte Carlo simulation using the bond fluctuation model. Phys Rev E 49 5420-5430, 1994. 

When adsorbed (from ambient air), water molecules might act as plasticizers and alter the dynamics of polymers. Moreover, water has a strong dipole moment and, consequently, dielectric active relaxation processes, which could partially occlude significant parts of the dielectric spectra of interest. Special attention to this effect has to be paid when the dynamics of thin polymer films is investigated, for example in relation to phenomena like the glass transition, dewetting, pattern formation, surface mobility etc. 

McCormick et al. (2003) studied the structure and dynamics of adsorbed water and polymer components in PEM films and the bulk PEC using H MAS NMR spectroscopy. The films (1-5 bilayers) with poly(diallyl dimethylammonium chloride) (PDADMAC) and poly(sodium-4-styrenesulfonate) (PSS) were adsorbed onto colloidal silica particles. Relaxation and line width measurements showed that the adsorbed water is less mobile in the films than in the analogous PEC. This result can be explained by compacting of the adsorption layer at a surface and enhancement of confined space effects for bound water. Relaxation measurements and H double-quantum (DQ) NMR experiments revealed that polymer dynamics in the PEMs was strongly influenced by the layer number and water content (Eigures 5.18 and 5.19). 2D spin... 

Detachment of Adsorbed Polymer Chain Statics and Dynamics... 

Several methods may be applied to determine the hydrodynamic thickness of adsorbed polymer layers, of which viscosity, sedimentation coefficient (using an ultracentrifuge) and dynamic light scattering measurements are the most convenient. A less accurate method is from zeta potential measurements. These techniques are based on hydrodynamic techniques and these are discussed below. 

Some dynamical features of adsorbed polymers , in Molecular Conformation and Dynamics of Macromolecules in Condensed Systems. M. Nagasawa (Ed.) Studies in Polymer Science, Volume 2, pages 315-331, Elsevier Science Publishers B.V., Amsterdam (1988) ... 

In principle every method suited for measuring some property of an adsorbed polymer as a function of time can be used for studying one or more aspects of the dynamics of polymer adsorption. Some methods can only be used for polymer adsorption on flat (oxidic) siufaces, others require higher amounts of adsorbed polymers and therefore can only be applied in dispersions with sufficient surface area. Recently some reviews on experimental methods have been published [1, 35]. In this section we will discuss some frequently applied methods applicable for oxidic surfaces. 

By means of neutron reflectivity [57] and neutron scattering [58] one can determine density profiles of adsorbed polymer layers, but the data acquisition time is usually of the order of hoius and therefore not very suitable for studying the dynamics of polymer layers. 

Measurements on Flat Surfaces. Using planar substrates, polymer adsorption can be studied under well-defined conditions of surface eneigies and known surface area. These measurements provide important insists into the structure and dynamics of adsorbed pol3rmers, which are often not experimentally achievable using dispersed particles. 

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