Prof. Sergei Egorov

Univ. of Virginia, USA

Tunable Cylindrical Brushes

Abstract

We present a self-consistent field theoretical study of the microstructure of concave cylindrical brushes as a function

of the cylinder radius, grafting density, grafted chain length, and the solvent quality. We show that the results for the

radial monomer density profile and the distribution of the free ends are in good agreement with the corresponding

molecular dynamics results.

In addition, we consider conformational behavior of a free macromolecule in a cylindrical brush. The central result

is the observed

non-monotonous variation of the size of a free chain in a brush-coated tube when the tube radius

is systematically changed. An interpretation of this behavior is given by considering the overlap between the free

polymer and the grafted chains as a function of the tube radius.

In the second part of the talk, we present a self-consistent field theoretical study of phase separation in binary

polymer brushes physisorbed on cylindrical surfaces. In agreement with earlier simulation and experimental work,

we find that macrophase separation occurs for two immiscible polymers of the same length, while chain length

mismatch between two polymer types promotes microphase separation, with ring-shaped alternating stripes forming

perpendicular to the cylinder axis. We observe that the width of the stripes increases with increasing immiscibility,

increasing substrate curvature, decreasing mismatch in the chain length, and decreasing amount of adsorbed polymer.

We rationalize these observations by analyzing entropic and energetic contributions to the Helmholtz free energy of

the system.



Date: 19/6/2015
Time:12:00 (coffee & cookies will be served at 11:45)
Place:FORTH Seminar Room 2