arXiv subjects

C. I. Addison

Publications and source records attributed to C. I. Addison.

4 recordsLinked to original sources

arXiv2005

Coarse-graining diblock copolymer solutions: a macromolecular version of the Widom-Rowlinson model

We propose a systematic coarse-grained representation of block copolymers, whereby each block is reduced to a single ``soft blob'' and effective intra- as well as intermolecular interactions act between centres of mass of the blocks. The coarse-graining approach is applied to simple athermal lattice models of symmetric AB diblock copolymers, in particular to a Widom-Rowlinson-like model where blocks of the same species behave as ideal polymers (i.e. freely interpenetrate), while blocks of opposite species are mutually avoiding walks. This incompatibility drives microphase separation for copolymer solutions in the semi-dilute regime. An appropriate, consistent inversion procedure is used to extract effective inter- and intramolecular potentials from Monte Carlo results for the pair distribution functions of the block centres of mass in the infinite dilution limit.

cond-mat.soft↗

arXiv2005

Polymer solutions: from hard monomers to soft polymers

A coarse-graining strategy for dilute and semi-dilute solutions of interacting polymers, and of colloid polymer mixtures is briefly described. Monomer degrees of freedom are traced out to derive an effective, state dependent pair potential between the polymer centres of mass. The cross-over between good and poor solvent conditions is discussed within a scaling analysis. The method is extended to block copolymers represented as "necklaces" of soft "blobs", and its success is illustrated here in the case of a symmetric diblock copolymer which exhibits microphase separation.

cond-mat.soft↗

arXiv2004

From concentration profiles to polymer osmotic equations of state

We show that equilibrium monomer and centre-of-mass concentration profiles of lattice polymers in a gravitational field, computed by Monte-Carlo simulations, provide an accurate and efficient road to the osmotic equation-of-state of polymer solutions, via a straightforward application of the hydrostatic equilibrium condition. The method yields the full equation of state over a wide range of concentrations from a single simulation, and does not suffer from significant finite size effects. It has been applied to self-avoiding walk polymer chains with nearest neighbour monomer attractions, from the good solvent to the theta solvent regimes. The consistency of the method has been carefully checked by varying the strength of the gravitational field.

cond-mat.soft↗

arXiv2004

Influence of solvent quality on polymer solutions: a Monte Carlo study of bulk and interfacial properties

The effect of solvent quality on dilute and semi-dilute regimes of polymers in solution is studied by means of Monte Carlo simulations. The equation of state, adsorptions near a hard wall, wall-polymer surface tension and effective depletion potentials are all calculated as a function of concentration and solvent quality. We find important differences between polymers in good and theta solvents. In the dilute regime, the physical properties for polymers in a theta solvent closely resemble those of ideal polymers. In the semi-dilute regime, however, significant differences are found.

cond-mat.soft↗