Macromolecular adsorbed layer

Figure 2. Schematic lattice representation of a macromolecular adsorbed layer showing adsorbed and nonadsorbed uncharged macromolecules. (Reproduced with permission from reference 11. Copyright 1985.)...

The final proof of the physical reality of our model of macromolecular adsorption was provided by simultaneous independent work, by an entirely different method, at the National Bureau of Standards (27). Stromberg et al., allowed polystyrene fractions, besides other polymers, to become adsorbed on ferrochrome plates and determined the thicknesses of the adsorbed layers... 

The answer to (a) is not necesseirlly, and that to (b) that depends. Regarding (a) we are dealing with non-equilibrium monolayers, of which the properties are partly determined by their history. Only when, in two experiments, exactly the same histories and the same experimental conditions can be met for the same chemicals, may the identity of observables be anticipated. Issues that play a role include the age of the interface before cycles are started in particular when the surfactant contains a minor, but very surface-active, compound there can be a substantial difference in the results between the situation where this minor component is already fully adsorbed, or starts to do so. The issue of Incomplete equilibration of the monolayer also plays its role in macromolecular adsorbates, which not only equilibrate notoriously slowly but also often exhibit non-linear behaviour. Once such a partly-equilibrated layer is subjected to compression-expansion cycles, the possibilities of further equilibration will depend on quantities such as AA and a, and these may be different in different methods. Nonlinearity of the phenomena may be another problem. 

The presence of a sharply defined interface between a polymer solution and a solid wall leads to important modifications in the local polymer concentration with respect to the bulk concentration. These variations can be positive or negative depending on the sign of the interaction between the solid wall and the macromolecular chains immersed in the solvent. Attractive forces lead to adsorbed layers while repulsive forces lead to depletion layers. Due to their connection with important technological applications such as adhesives, protective coatings, microlithography, emulsion stabilizers, adsorbed polymer layers have been the subject of extensive theoretical studies. ... 

The forces acting between atomically smooth mica surfaces immersed in both organic and aqueous liquid media have been determined in the range of surface separations 0 - 300 nm, both in the absence and the presence of adsorbed polymer layers. In this way the interactions between the adsorbed macromolecular layers themselves were determined. We present results for the following cases i) Poor solvent, ii) 0 - solvent, iii) good... 

The substantial thickness of adsorbed polymer layers has important consequences for many systems that contain macromolecular components. When adsorbed, e.g., on the particles of fluid dis-... 

King, S. Griffiths, P. Hone, J. Cosgrove, T. SANS from adsorbed polymer layers. Macromolecular Symposia 2002, 190, 33 2. 

A broad review of the effects of macromolecular compounds in disperse systems has been presented by Heller (311). He discusses the adsorption characteristics of polymer. molecules which on the one hand, are adsorbed at the surface with a terminal segment only, with the remainder of the chain protruding from the surface radially, and on the other hand, are adsorbed lying flat with all segments attached to the surface. Both situations can occur, of course, depending on the nature of the polymer and how much of an excess over the amount required to form a flat monomolecular layer is present. 

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