Block Copolymers Under Shear Flow

Stability of parallel/perpendicular domain boundaries in lamellar block copolymers under oscillatory shear

We introduce a model constitutive law for the dissipative stress tensor of lamellar phases to account for low frequency and long wavelength flows. Given the uniaxial symmetry of these phases, we argue that the stress tensor must be the same as that of a nematic but with the local order parameter being the slowly varying lamellar wavevector. This assumption leads to a dependence of the effective...

Adhesion under Shear Flow

The 4 integrin, 4 7, plays an important role in recruiting circulating lymphocytes to the gastrointestinal tract, where its ligand mucosal addressin cell adhesion molecule-1 (MAdCAM-1) is preferentially expressed on high endothelial venules (HEVs). Dual antagonists of 4 1 and 4 7, N-(2,6-dichlorobenzoyl)-(L)-4-(2 ,6 -bis-methoxyphenyl)phenylalanine (TR14035) and N-{N-[(3,5-dichlorobenzene)sulfo...

Erythrocyte deformation under shear flow.

Lamellar phase stability in diblock copolymers under reciprocating shear flows

A mesoscopic model of a diblock copolymer is used to study the stability of a uniform lamellar phase under a reciprocating shear flow. Approximate viscosity contrast between the microphases is allowed through a linear dependence of the (Newtonian) shear viscosity on monomer composition. We first show that viscosity contrast does not affect the composition of the base lamellar phase in an unboun...

Motion of a transverse/parallel grain boundary in a block copolymer under oscillatory shear flow

A mesoscopic model of a diblock copolymer is used to study the motion of a grain boundary separating two regions of perfectly ordered lamellar structures under an oscillatory but uniform shear flow. The case considered is a grain boundary separating lamellae along the so called parallel orientation (with wavevector parallel to the velocity gradient direction) and along the transverse orientatio...