Molecular dynamics simulations are used to study interfacial interaction and diffusion properties of CNT/polymer chains. It shows that —CH₃ decreases interfacial interaction energies of PE/CNT and PP/CNT systems. However, interfacial interaction energy of CNT/PEO modified with —CH₃ is increased. Compare interaction energies between pure CNT and PE, PP and PEO, we found that the interfacial interaction energy increased as CNT modified with —OH and —COOH. And the strength satisfies —COOH<—OH. Besides, total energies of PE/CNT, PP/CNT and PEO/CNT modified with —CH₃, —OH and —COOH are reduced. The decrease rate follows rule: —COOH < —OH < —CH₃. Coulomb energy plays the main role in the non-bond energies rather than vdW energy. Moreover, diffusion coefficient of functional CNT/PE, CNT/PP and CNT/PEO are obviously reduced by the impose of function groups, and the diffusion coefficient of the polymer chains satisfy —COOH<—OH<—CH₃.

Binding energy, electronic structure and optical properties of pure AlN and Ag, S codoping AlN were calculated with first-principles ultrasoft pseudopotential approach of plane wave based upon density functional theory.It shows that concentration of doping Ag atoms can be increased in AlN and acceptor level becomes shallower by introduction of S atoms. Acceptor Ag atoms play an important role in activating. So Ag, S codoping AlN is expected as an efficient means of p-type doping.Imaginary part of dielectric function and optical absorption spectrum of the doping system show a new peak in low energy region.And absorption edge extends to low energy. Doping system enhances low frequency electromagnetic wave absorption.