Statistical Properties of a Polymer Chain in the Environment with Low Concentration of Nanoparticles

Dessalegne A. Tsehay, Meng-Bo Luo Department of Physics, Zhejiang University, Hangzhou 310027, China

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We have investigated the statistical properties of polymer in the environment with low concentration of nanoparticles by using large-scale molecular dynamics simulations. The scaling law for the mean square radius of gyration was examined and simulation results for the polymer lengths 64≤N≤144 yielding a reasonably accurate value of the Flory exponent ν=0.58 at weak polymer-nanoparticle interaction εPN. Within the same range of N, the mean asphericity of the chain is independent of N. We found that the polymer behaves like a self-avoiding walk chain at small εPN and a compact sphere at large εPN. The results are attributed to the increase in the contact between polymer and nanoparticles with increasing εPN. Normal diffusions of polymer are always observed at whatever εPN and size and concentration of nanoparticles. Our result shows that the normal diffusion behavior of polymer is independent of polymer's state even though there is a phase transition from a desorbed polymer phase at small εPN to an adsorbed polymer phase at large εPN.

DOI:10.12693/APhysPolA.133.1274 topics: diffusion, conformation, polymer chain, nanoparticles, molecular dynamics