|Title||Nanorheology of Entangled Polymer Melts|
|Publication Type||Journal Article|
|Year of Publication||2018|
|Authors||T Ge, GS Grest, and M Rubinstein|
|Journal||Phys Rev Lett|
We use molecular simulations to probe the local viscoelasticity of an entangled polymer melt by tracking the motion of embedded nonsticky nanoparticles (NPs). As in conventional microrheology, the generalized Stokes-Einstein relation is employed to extract an effective stress relaxation function GGSE(t) from the mean square displacement of NPs. GGSE(t) for different NP diameters d are compared with the stress relaxation function G(t) of a pure polymer melt. The deviation of GGSE(t) from G(t) reflects the incomplete coupling between NPs and the dynamic modes of the melt. For linear polymers, a plateau in GGSE(t) emerges as d exceeds the entanglement mesh size a and approaches the entanglement plateau in G(t) for a pure melt with increasing d. For ring polymers, as d increases towards the spanning size R of ring polymers, GGSE(t) approaches G(t) of the ring melt with no entanglement plateau.
|Short Title||Phys Rev Lett|