8/17/2023 0 Comments Fission sv temperature rating![]() ![]() In this phase the bilayer mid-surface has a mean curvature close to zero and a negative Euler characteristic. In addition to the anisotropic lamellar phase (L-alpha) there is also, at slightly higher temperature, a sponge or L-3-phase where the bilayers build up an isotropic structure extending macroscopically in three dimensions. In contrast, the lamellae-to-sponge transformation apparently occurs through a succession of uncorrelated bilayer fusion events.Ībstract = "The system water-oil (n-decane)-nonionic surfactant (C12E5) forms bilayer phases in a large concentration region, but, for a given oil-to-surfactant ratio, only in a narrow temperature range. We find that the sponge-to-lamellae transition occurs through a nucleation process followed by domain growth involving bilayer fission at domain boundaries. We here report on the first experiments concerned with the dynamics of the macroscopic phase transition sponge-lamellae by H-2-NMR. ![]() At phi<0.1 the relaxation times are so slow that experiments using deuterium nuclear magnetic resonance (H-2-NMR) appear feasible. These experiments revealed an extraordinarily strong dependence of the relaxation time on the bilayer volume fraction phi. Such dynamic processes have previously been monitored by temperature jump experiments using light scattering in the sponge phase. The equilibration therefore involves kinetic steps of fusion/fission of bilayers. The monolayer spontaneous curvature depends sensitively on temperature and a change of temperature thus provides a driving force for a change in bilayer topology. In this paper we study how the bilayers in the lamellar and the sponge phase respond dynamically to sudden temperature changes. The system water-oil (n-decane)-nonionic surfactant (C12E5) forms bilayer phases in a large concentration region, but, for a given oil-to-surfactant ratio, only in a narrow temperature range. ![]()
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