Polymer chains in crowded environments often show subdiffusive behavior. We adopt molecular dynamics simulations to study the conditions for the subdiffusion of polymer chains in crowded environments containing randomly distributed,...

The glass transition and dynamics of densely grafted semiflexible polymer brushes are studied by molecular dynamics simulation. The glass transition temperature (Tg) increases with the polymer rigidity. The local glass...

The dynamical and conformational properties of polymer chains are affected significantly by strongly attractive nanoparticles. The adsorption of polymer chains on nanoparticles not only reduces the dynamics but also changes...

Dry polymer brushes have attracted great attention because of their potential utility in regulating interface properties. However, it is still unknown whether dry polymer brushes will exhibit degrafting behavior as a result of thermal annealing. Herein, a study of the conformational entropy effect on thermal degrafting of dry polystyrene (PS) brushes is presented. For PS brushes with an initial grafting density (σp ini) of 0.61 nm–2, degrafting behavior was observed at 393 K, and the equilibrium σp was approximately 0.14 nm–2 at 413 K. However, for brushes with σp ini ≤ 0.14 nm–2, thermal degrafting was not observed even if the temperature was increased to 453 K. Furthermore, we found that the degrafting rate was faster for PS brushes with higher σp ini and higher molecular weights when σp ini > 0.14 nm–2. Our findings confirmed that degrafting is a mechanochemical activation process driven by tension imposed on bonds that anchor the chains to the surface, and the process is amplified by conformational entropy.

Adsorption of polymer chains on solid surface is a universal interfacial behavior. Loops in the adsorbed chains are considered to exert significant effect on the overall properties of substrate-supported polymer...