The effect of shear on ordered block copolymer solutions

Block copolymers are extensively used in solution, especially aqueous solut ion, because of their amphiphilic character. This leads to the formation of lyotropic mesophases under given conditions of concentration and temperatu re. In many applications, block copolymer solutions are subjected to shear during processing (for example in drug delivery or when washing in detergen t solutions) and thus it is of considerable interest to understand how shea r affects the mesophase structure. Recent research has focussed on probing shear-induced structural transformations in lamellar, hexagonal and cubic-p acked micellar phases using small-angle X-ray and neutron scattering. (C) 2 000 Elsevier Science Ltd. All rights reserved.