Interaction of polymer with discotic clay particles

摘要

Normally synthetic well defined monodisperse discotic laponite clays are known to211u001eform a gel phase at mass concentrations as low as a few percent in distilled 211u001ewater. Hydrosoluble polymer polyethylene oxide was added to this intriguing clay 211u001esystem, it was observed that it either prevents gelation or slows it down 211u001eextremely depending on the polymer weight, concentration or the laponite 211u001econcentration. Small Angle Neutron scattering (SANS) was used to study these 211u001esystems because only by isotopic labeling can the structure of the adsorbed 211u001epolymer layers be determined. The contrast variation technique is specifically 211u001eused to determine separately the different partial structure factors of the clay 211u001eand polymer. In this way the signal of the adsorbed chains is separated from the 211u001esignal of the free chains in the dilute regime. Attempts have also been made to 211u001echaracterize the structure in the concentrated regime of laponite with polymer.