Ordering of the lamellar phase under a shear flow
نویسندگان
چکیده
منابع مشابه
Oscillating viscosity in a lyotropic lamellar phase under shear flow.
We report some time-dependent behavior of lyotropic lamellar phase under shear flow. At fixed stress, near a layering instability, the system presents an oscillating shear rate. We build up a new stress versus shear rate diagram that includes temporal behavior. This diagram is made of two distinct branches of stationary states which correspond, respectively, to disordered and ordered multilamel...
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In this paper, we incorporate some real-system effects into the theory of orientational phase transitions under shear flow [M. E. Cates and S. T. Milner, Phys. Rev. Lett. 62 1856 (1989) and G. H. Fredrickson, J. Rheol. 38, 1045 (1994)]. In particular, we study the influence of the shear-cell boundaries on the orientation of the lamellar phase. We predict that at low shear rates, the parallel or...
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Small-angle neutron scattering was employed to study the effect of shear flow on the nematic (N) and lamellar (La) phases in aqueous solutions of cesium perfluoro-octanoate. Shear rates as high as 4000 s-l were used. The N phase was found to align with the director in the direction of the gradient velocity. The L, phase oriented with lamellae parallel to the shear plane. This change in equilibr...
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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...
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Self-assembled lamellar structures composed of block copolymers are simulated by molecular dynamics. The response of a bulk system to external shear is investigated, in particular, the average energy, the entropy production, and the stability of the lamellae's orientation. We distinguish two orientations, a parallel orientation in which the normal to the lamellae sheets lies in the direction of...
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ژورنال
عنوان ژورنال: Physical Review E
سال: 2002
ISSN: 1063-651X,1095-3787
DOI: 10.1103/physreve.66.016114