Less-Concentrated HPAM Solutions as a Polymer Retention Reduction Method in CEOR

Concentrated polymer solutions in the presence of fixed obstacles

Entanglement-controlled subdiffusion of nanoparticles within concentrated polymer solutions.

We describe x-ray photon correlation spectroscopy (XPCS) experiments tracking the motion of gold nanoparticles within solutions of high-molecular-weight polystyrene. Over displacements from nanometers to tens of nanometers, the particles undergo subdiffusive motion that is dictated by the temporal evolution of the entangled polymer mesh in the immediate vicinity of the particles. The results th...

Molecular dynamics simulations of dielectric relaxation of concentrated polymer solutions

Molecular dynamics simulations are conducted for concentrated solutions of flexible polymers. The results are contrasted with literature dielectric spectroscopy data, in an attempt to elucidate the observed phenomena from a molecular level perspective. A bead-spring model is used and systems with chain sizes up to N5150 beads at reduced densities 0.5<r<0.8 are studied. The dimensions of the cha...

Drag reduction and solvation in polymer solutions

A model is described which explains drag reduction (DR) in dilute polymer solutions in terms of solvation of macromolecular chains and formation of relatively stable domains. The domains partly suppress the vortex formation, act as energy sinks, and also play a role in mechanical degradation in flow (MDF). We report ultrasonically determined solvation numbers for a series of copolymers with the...

Diffusion Coefficients in Polymer- Solvent Systems for Highly Concentrated Polymer Solutions

The Vrentas/Duda proposal for the diffusion of polymer-solvent systems, which is based on the free-volume theory, was employed in correlating and predicting mutual diffusion coefficients in highly concentrated polymer solutions. It has been observed that the predictive version of the model is capable of qualitatively representing the experimental data, while the use of an adjustable parameter g...