Chemical binders or processing aids have been widely used to control processing conditions of fine powders by changing the intrinsic cohesivity of the solid material and/or the filler-media interactions. This study is aimed at achieving this control with polymers that are responsive to external stimuli, such as temperature. In this paper, we will examine aggregation and dispersion of silica clusters induced by the temperature dependent conformational changes in an adsorbed layer of poly(N-isopropyl acrylamide) (PNIPAM). Experimental studies of silica powder incorporating PNIPAM and water were performed at low and high temperatures. Results show that as the PNIPAM undergoes a coil to globule transition with an increase in temperature, modifications in the interparticle interactions of the PNIPAM-treated powders take place. This dependence of the cluster morphology and cohesivity on temperature was evidenced through changes in the aggregate particle size and in the dispersion mechanism and kinetics for the treated silica clusters.

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