Concentration fluctuations in polymer solutions under mixed flow

Slip, concentration fluctuations and flow instability in sheared polymer solutions

Recent experiments suggest that shear-enhanced growth of concentration fluctuations in polymer solutions is strongly influenced by solid boundaries. We analyze the dynamics of a model of a sheared polymer solution, accounting for the effect of stress variations on mass flux and for wall-slip. If (and only if) these effects are present, the flow exhibits a boundary-localized instability consiste...

Concentration Fluctuations in a Polymer Solution under a Temperature Gradient

We have performed small-angle Rayleigh light-scattering measurements in polymer solutions under various externally applied temperature gradients. Our experiments confirm the existence of an enhancement of the concentration fluctuations. The nonequilibrium concentration fluctuations are proportional to s=Td2yk4, where =T is the applied temperature gradient, and k is the wave number of the fluctu...

Flow enhancement of electrical fluctuations in polymer solutions and melts

We show that the origin of the enhanced electrical fluctuations under flow, observed over the last is years in polymer solutions, can be traced back to a dissipative cross coupling between the strain tensor (characterizing transient polymeric networks) and electric fields. Additional experiments to further test our picture are suggested.

Light scattering from nonequilibrium concentration fluctuations in a polymer solution

Concentration and energy fluctuations in a critical polymer mixture.

A semi-grand-canonical Monte Carlo algorithm is employed in conjunction with the bond fluctuation model to investigate the critical properties of an asymmetric binary (AB) polymer mixture. By applying the equal peak-weight criterion to the concentration distribution, the coexistence curve separating the A-rich and B-rich phases is identified as a function of temperature and chemical potential. ...