Adsorption of poly(ethylene oxide) with different molecular weights on the surface of silica nanoparticles and the suspension stability

Adsorption of poly(ethylene oxide) (PEO) with different molecular weights (Mws) in aqueous suspension on the surface of silica nanoparticles and the stability of suspension dispersion were studied. Adsorption isotherms demonstrate that the plateau-adsorbed amount of polymer is related to Mw. Results of infrared analysis indicate that PEO is adsorbed on silica through a hydrogen bonding between –SiOH and ether oxygen of PEO molecule. The change in |ζ| of silica suspensions after adsorption varies distinctly with different Mw, and the main factors responsible for the changes and the stability mechanisms of suspension were discussed. Using the appropriate Mw PEO, a highly stabilized dispersion can be achieved at a certain concentration.