0000000000297384
AUTHOR
Harry L. Frisch
Surface effects on spinodal decomposition in binary mixtures: The case with long-ranged surface fields
We present detailed numerical results for phase-separation kinetics of critical binary mixtures in the vicinity of a surface that exerts a long-ranged attractive force on one of the components of the mixture. We consider surface potentials of the form $V(Z)\ensuremath{\sim}{Z}^{\ensuremath{-}n}$, where $Z$ is the distance from the surface and $n=1,2,3$. In particular, we investigate the interplay of the surface wetting layer with the dynamics of domain growth. We find that the wetting layer at the surface exhibits power-law growth with an exponent that depends on $n$, in contrast to the case with a short-ranged surface potential, where the growth is presumably logarithmic. From correlation …
Surface critical behaviour near the uniaxial Lifshitz point of the axial next-nearest-neighbour Ising model
The semi-infinite axial next-nearest-neighbour Ising (ANNNI) model in the disordered phase is treated within a molecular-field approximation, and the singularities of various response functions characterizing the critical behaviour at the surface are obtained. In previous work (Binder K and Frisch H L 1999 Eur. Phys. J. B 10 71) the axis where a nearest-neighbour ferromagnetic (J 1 ) and next-nearest-neighbour antiferromagnetic (J 2 ) exchange compete was chosen perpendicular to the surface plane. In the present work we consider an orientation of this axis parallel to the surface, allowing also for different values of these exchange interactions (j 1 ,j 2 ) in the surface plane. We derive t…
Surface-directed spinodal decomposition: modelling and numerical simulations
We critically review the modelling and simulations of surface-directed spinodal decomposition, namely, the dynamics of phase separation of a critical or near-critical binary mixture in the presence of a surface with a preferential attraction for one of the components of the mixture.
Monte Carlo simulation of DNA electrophoresis
This paper describes an attempt to study the electrophoresis mobility of a DNA molecule in a gel by means of a Monte Carlo simulation. We find that the electrophoresis mobility mu can be well described by the empirical equation mu v kappa 1/N + kappa 2E2 with N being the number of monomers of the model chain and E being the applied field. For small E the data can merge into the linear response result mu = kappa 1/N. The paper also discusses necessary extensions of the present approach.
Dynamics of star polymers in a good solvent: A Kramers potential treatment
The ‘‘effective’’ relaxation time τ of isolated star polymers with excluded volume interactions in the Rouse model limit (i.e., disregarding hydrodynamic interactions present in real solvents) is studied varying both the number of arms f and the number of monomers per arm l. Here τ is defined from the response of the gyration radius of the star polymer to a Kramers potential that describes the effect of shear flow in lowest order in the shear rate. Monte Carlo simulations are performed with two different techniques (simple sampling with enrichment or dynamic Monte Carlo, respectively) for two different models (simple self‐avoiding walks with an extended core or the bond fluctuation model, r…