Polymer-coated surfaces

Following the arguments by Van Loosdrecht et al. (1990) schematically the interaction between the (negatively charged) cell surface and the solid surface - a sulphated polystyrene surface (hydrophobic, negatively charged) - in presence of polymers, that have adsorbed to both surfaces can be shown to be caused by various interaction energies between the two partially or totally polymer-coated surfaces (Fig. 7.19). The effects of polymers have been interpreted (Van Loosdrecht et al., 1990) as follows ... 

Scheme 3 a Iniferter-derivatized polymer-coated surface, b Iniferter-derivatized surface... 

Whether a polymer is grafted on the surface or simply adsorbed on the surface has a bearing on the force between two polymer-coated surfaces. Adsorption is a reversible process and can be affected by temperature, compression of the polymer layer, and the like. 

FIG. 13.16 Interaction forces between polymer-coated surfaces and their dependence on the type of layers and quality of the solvents. (Redrawn with permission from Israelachvili 1991.)... 

This repulsion was calculated by different authors [201,202], For a low grafting density (T < 1 /R2g), the repulsive force per unit area in a good solvent and between two polymer coated surfaces is [200]... 

For two polymer coated surfaces, a simple extension of Reynolds formula for the lubrication force gives [4,60]... 

Blattler, T. M. Covalent Immobilization of Poly(L-lysine)-g-poly(ethylene glycol) onto Aldehyde Plasma Polymer Coated Surfaces. Diploma Thesis, University of South Australia, 2004. 

Ellipsometry measures the relative attenuation and phase shift of polarized light reflected from a polymer-coated surface. The Drude equations (Drude, 1889a,b, 1890 Stromberg et ai, 1963 McCrackin and Colson, 1964) relate the attenuation and phase shift to the average refractive index and thickness tel of an equivalent homogeneous film. Interpretation of fel in terms of the actual refractive index distribution or the polymer distribution [Pg.189]

Cellular adhesion FFF combines the controllable hydrodynamic shear forces of FFF and the selective adhesion of AC. The hydrodynamic shear is used to detach selectively and evenly adhered cells or particles from the surface and allows an estimation of the differences in cell/surface adhesion forces. The channel for cellular adhesion FFF is constructed in the same way as that used for Gr-FFF but is smaller in size and with the modification that the accumulation wall consists of either bare or polymer-coated surfaces. After the cell suspension is filled into the channel allowing sufficient time for cell adhesion, the flow is applied and fractions are collected. Despite the collection of fractions, cellular adhesion FFF can also be used as a tool to study rapid kinetics of cell surface adhesion, a largely unexamined area [332]. 

Figure 31.14 Polarization resistance of [2A] panels with different chemical pretreatments and TMS plasma polymer-coated surfaces.

Figure 31.26 Rp values of AA2024-T3 ([2B]), AA7075-T6 ([7B]), Alclad 2024-T3 ([2A]), and Alclad 7075-T6 ([7A]) panels with different chemical pretreatments and plasma polymer-coated surfaces.

The long-range repulsive force increases somewhat when the polyelectrolyte concentration is increased to above 20 ppm. This indicates that the charges in the adsorbed polyelectrolyte layer slightly overcompensate the charge of the substrate surface, and that the polymer-coated surface now has a net positive charge. It is interesting to note that under these conditions the... 

Adsorption onto polymer-coated surfaces has also been attempted [1]. Polystyrene was used, presumably to mimic the binding capabilities of enzyme linked immunosorbant assay (ELISA). While the method showed good binding of the antibodies the sensor had a low sensitivity to cells. This was... 

The applications of the SFM include force measurement between surfaces in liquid and vapor, adhesion between similar or dissimilar materials, contact deformation, wetting and capillary condensation, viscosity in thin films, forces between surfactant and polymer-coated surfaces, and surface chemistry. Fluid-electrolyte interactions between conductive surfaces can also be measured [Smith, et. al., 1988]. A typical microforce of 10 nN can be detected over separation distances to a resolution of 0.1 nm with optical interoferometry between reflective surfaces. With electrostatic forces, relatively large separation are measured 1-100 nm, whereas, short range forces such as van der Waals forces take place over distances of less than 3.0 nm. Ultrasmooth and electrically conductive surfaces can be formed by the deposition of a metal film (40 nm thickness) such as Pt on a smooth substrate of mica [Smith, et. al., 1988]. The separation distance between the two surfaces is controlled by a... 

Fig. 3.7. A setup scheme for studying capillary flow of liquids over the polymer coatings surface...

FIGURE 4.7 SAW velocity and attenuation changes vs. shear wave phase shift (i) for several values of film loss parameter. The dashed line corresponds to prediction using Tiersten formula. (Reprinted with permission from Martin S. J., Frye G. C., and Senturia S. D., Dynamics and response of polymer-coated surface acoustic wave devices Effect of viscoelastic properties and film resonance, Anal. Chem., 66, 2201-2219, 1994. Copyright (1994) American Chemical Society.)... 

Martin S. J., Frye G. C., and Senturia S. D., Dynamics and response of polymer-coated surface acoustic wave devices Effect of viscoelastic properties and film resonance. Anal. Chem., 66, 2201-2219, 1994. 

Reported studies include various deposition and dissolution processes [876,908] and mechanistic studies of electrode processes at redox-active polymer-coated surfaces [909-912]. In a typical study of a polymer film containing ruthenium ions as redox-active centers, a cyclic voltammogram indicative of the one electron transfer at this center is observed as depicted in Fig. 5.144. The movement of ions needed for charge compensation in the film after a change of the redox state can be detected with PBD. The positive-going response during oxidation of the ruthenium center... 

Chlorobenzene Dimer acid, hydrogenated Epoxy, bisphenol F N-(p-Ethoxycarbonylphenyl)-N -ethyl-N -phenylformamidine 2,2, 4,4, 5,5 -Hexachlorobiphenyl Polychlorinated biphenyls coatings, surface film Tetrahydrofuran coatings, surface lipophilic Octadecyltrichlorosilane coatings, surface PU paints Hexamethylene diisocyanate biuret Hexamethylene diisocyanate polymer coatings, surface PU varnishes Hexamethylene diisocyanate biuret Hexamethylene diisocyanate polymer coatings, surface textiles Tetrahydrofuran... 

Gibson, J. B., Chen, K., and Chynoweth, S. Simulation of particle adsorption onto a polymer-coated surface using the dissipative particle dynamics method. J Colloid Interface 5cz., 206,464-74 (1998). 

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