The influence of shear on the mesoscopic structure in the lamellar region of ternary poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) block copolymers PEO_(20)-b-PPO_(70)-b-PEO_(20) and PEO_(100)-b-PPO_(70)-b-PEO_(100) (Pluronic P123 and F127)/water/butanol systems was investigated by different techniques namely: small angle neutron and light scattering (SANS, SALS), as well as birefringence. A transition from parallel to perpendicular alignment of lamellae, with a corresponding decrease in the viscosity, was found with increasing shear rate at high block copolymer concentrations. However, a shear-induced formation of multilamellar vesicles ("onions") was observed when the polymer concentration was reduced.
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