Interparticle Interaction between Functionalized Clay Nanosheets Dispersed in Polymer Matrix

Incorporation of nanofillers in polymer melt produces composites with extra-ordinary properties due to enhanced surface to volume ratio of the fillers. Fillers are functionalized by grafting polymeric chains on the surface inducing steric stabilizing preventing particle agglomeration. Here, we address the dispersion of clay nanosheets in polymer matrix. We use self-consistent field theory to theoretically construct the polymer mediated interparticle potential curve. The interaction potential is obtained from the inhomogeneous composition field for the polymer segments. First, we examine the interpaticle interaction between two grafted nanosheets immersed in the matrix of polymeric chains of dissimilar chemistry to that of the grafted chains. The interaction potential is repulsive at short separation and shows depletion attraction for moderate separations. Further, we construct the interaction potential between two nanosheets grafted with polymeric chains of varying architectures, like star polymer and diblock copolymer. Nanosheets disperse better in the matrix of star polymer than linear polymer. In surfaces grafted with diblock copolymers, the interplay between the enthalpic and entropic interaction gives rise to a rich behavior in the interparticle interaction potential curve.