ADSORPTION OF END-FUNCTIONALIZED POLYMERS ON COLLOIDAL SPHERES

We report a light scattering study of the adsorption of end-functionalized polymers on colloidal spheres. A light scattering method is developed to measure the amount of polymer molecules adsorbed on the colloidal surfaces. The experiment reveals that only a fraction of the end-functionalized polymers is adsorbed on the colloidal surface. The results for the end-functionalized polymers are compared with those for the unfunctionalized polymer. It is found that the interaction be-tween the colloid and the unfunctionalized polymer is repulsive, which introduces a depletion attraction between the colloidal particles. The functional end groups are found to interact attractively with the polar cores of the colloidal particles. The adsorption energy between the functional group and the colloidal surface is estimated to be approximately 4k(B)T. The experiment shows that the presence of the adsorbed polymer on the colloidal surfaces greatly reduces the depletion attraction between the colloidal particles and, therefore, enhances the stability of the colloid-polymer mixture.