Extensional Flow Induced Phenomena in Entangled Polymers: Three Easy Pieces

Abstract: This presentation summarizes recent MRAIL Group simulations of entangled polyethylene (C₁₀₀₀H₂₀₀₂) solutions and melts under planar and uniaxial elongational flow. Nonequilibrium molecular dynamics of solutions in n-hexadecane (14.5 C) and benzene (13.5 C) show that both systems undergo flow induced chemical phase separation when extension rates exceed the inverse Rouse time. Phase separation begins after ~2 Hencky strains and reaches steady state near 10. At very high extension rates, semicrystalline domains form in the polymer rich phase, with the critical rate depending on temperature and solvent chemistry. If time permits, we will discuss our recent work on atom scale crystallinity tracking, which integrates C index metrics, entropy based descriptors, and the ClusTEK ML/AI framework to consistently identify ordered regions, follow their evolution, and characterize the morphology of growing clusters.

This event is sponsored by FAMU-FSU College of Engineering and Department of Chemical & Biomedical Engineering.

Presented by: Bamin Khomami, Ph.D.

Granger and Beaman Distinguished University Professor

University of Tennessee, Knoxville