Polymer melt/solid and polymer melt/vacuum interfaces are encountered in many technologies involving adhesives, coatings, lubricants, and composite materials, where adsorbed molecules control the overall performance of the multiphase material system. We are using hierarchical simulation approaches to study such interfacial systems. Our methods include Mote Carlo techniques for the equilibration of long atomistic polymers near to solid surfaces and long atomistic MD simulations to study the mobility of the polymer chains near to the substrate.


Recently [1,2] we obtained simulation predictions concerning chain mobility and diffusion in thin films of polyethylene melts adsorbed on graphite, obtained through detailed atomistic molecular dynamics (MD) simulations. The long-time diffusion coefficient of adsorbed segments normal to graphite has been calculated by mapping MD trajectories onto the solution of a macroscopic diffusion equation. Extracted self diffusion coefficients are reported as a function of film thickness; their dependence on chain length is also discussed. 

Then mesoscopic dynamic simulations in the CG level are performed. The proposed CG is tested along a different number of structural properties, i.e. on the monomeric level (distribution function of bonds, bending and dihedral angles) as well as on the level of the whole chain (internal distances, radius of gyration, end-to-end distance). This approach also allows to distinguish stereoregular polymer systems.





Polymer/Solid Interfaces