Concentration and energy fluctuations in a critical polymer mixture

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. ...

Critical Fluctuations of a Confined Binary Mixture

Exploiting the mapping between a binary mixture and the Ising model we have analyzed the critical fluctuations by means of the density-matrix renormalization group technique. The calculations have been carried out for a two-dimensional Ising strip subject to equally strong surface fields. It was found that the critical Casimir force has significantly different behavior on opposite sides of the ...

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...

Light scattering from nonequilibrium concentration fluctuations in a polymer solution

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...