Nano continua processes

Although continuum mechanics have been well accepted to describe the nonlinear dynamies and fi ee-surface jet flows in maero seale [2], the eontinuum modeling is not applieable when nano-seale or molecular level physics become dominant,. In addition to experimental investigation, molecular dynamic (MD) simulation is a powerful tool to study nano-scale processes under different operating conditions. Recently, many researchers reported MD simulation results for nano-jet formation [3,4]. 

On the nano-scale, the discrete moleculai structure of the polymer has to be considered. Segmental immobilization seems to be the primary reinforcing mechanism in true polymer nanocomposites at temperatures near and above the Tg. Reptation model and simple percolation model were used to describe immobilization of chains near solid nanopaiticles and to explain the peculiarities in the viscoelastic response of polymers near solid surfaces of lar ge polymer-inclusion contact areas. The inteiphase in the continuum sense does not exist at the nano-scale when relaxation processes in individual discrete chains are taken into account and the chains with retarded reptation catr be considered forming the iirterphase analogue irr the discrete matter. For a common polymer, all the chains in the composite are immobilized when the internal filler-matrix interface area reached about 42 m per 1 g of the nanocomposite. 

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