Surface modification by polymers

Surface modification by polymer adsorption is an alternative to surface modification by polymer grafting. For example, polystyrene nanospheres coated by Poloxamer or Poloxamine (Ilium and Davis, 1983 Muller, 1991) or poly(methyl methacrylate) colloidal carriers coated by Poloxamer (Trds-ter and Kreuter, 1988) circulate longer in blood. This family of surfactants consist of poly(propylene glycol) (PPG) blocks, which adsorb on the hydrophobic polystyrene surface, and of more hydrophilic PEG blocks, which stick out of the surface in aqueous solutions and prevent opsonin adsorption. In spite of the increase in blood circulation time, particle coating by polymer adsorption was found to have several drawbacks (Petrak, 1993) ... 

Surface modification by polymers is an effective method of enhancing polymer-clay compatibility. There are two mechanisms for surface modification of clay minerals with polymers (i) physical adsorption and (ii) chemical grafting of functional polymers onto the clay surface. Physical adsorption modifies the surface properties of clay, but the structure of the clay mineral is preserved. However, the forces between the adsorbed molecules and the clay mineral might be weak, causing desorption. Grafting of functional polymers onto the surfaces of clay minerals provides stronger clay-polymer interaction and permits control... 

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