Study Of Conformations Of Polymer Chain In Nanocomposites And The Dispersion Of Nanoparticles

The effect of the polymer chain topology structure on the adsorption behavior and the effect of polymer conformations on nanoparticle dispersion in the polymer-nanoparticle(NP)interface is investigated by employing coarse-grained molecular dynamics simulations in various polymer-NP interaction and chain stiffness.At a weak polymer-NP interaction,ring chain with a closed topology structure has a slight priority to occupy the interfacial region than linear chain.At a strong polymer-NP interaction,the ‘middle' adsorption mechanism dominates the polymer local packing in the interface.As the increase of chain stiffness,an interesting transition from ring to linear chain preferential adsorption behavior occurs.The semiflexible linear chain squeezes ring chain out of the interfacial region by forming a helical structure and wrapping tightly the surface of NP.In particular,this selective adsorption behavior becomes more dramatic for the case of rigid-like chain,in which 3D tangent conformation of linear chain is absolutely prior to the 2D plane orbital structure of ring chain.The local packing and competitive adsorption behavior of bidisperse matrix in polymer-NP interface can be explained based on the adsorption mechanism of monodisperse(pure ring or linear)case.The conformations of ring polymer chain and the dispersion behavior of nanoparticle in nanocomposites are investigated by using coarse-grained molecular dynamics.With the increasing of polymer-NP interaction,nanoparticles perform three dispersion-aggregation states : contact aggregation,dispersion and telebridging aggregation,which are consistent with the theoretical results.By changing the stiffness of ring chain,three typical conformations are obtained: middle adsorption,saddle-shaped adsorption and obit-shaped adsorption.The increasing of ring chain stiffness is benefit for the dispersion of nanoparticle in nanocomposites.These investigations may provide some insights into polymer-NP interfacial adsorption behavior and guide the design of highperformance nanocomposites.