Dynamic phase diagram and onion formation in the system C10E3/D2O

Oliviero, Cesare; Coppola, Luigi; Gianferri, Raffaella; Nicotera, Isabella; Olsson, Ulf

doi:10.1016/s0927-7757(03)00356-x

Cited by 55 publications

(102 citation statements)

References 21 publications

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“…Hence, from the viscosity experiments we conclude that a steady state can be reached, independent of the shear history, at least if the shear rate is >10 s )1 . The MLVs are shear thinning and the viscosity values obtained here are similar to the ones obtained by Oliviero et al [32] at slightly higher temperatures.…”

Section: Polarized Light Microscopysupporting

confidence: 90%

“…Panizza et al [6] found two different regimes in the size changes of MLVs that depended on the initial and final shear rates. Mu¨ller and collaborators [7] reported reversibility in a related system, C 12 E 4 /D 2 O and, in the present work, we investigated the reversibility in the MLV size distribution during stepwise cycling of the shear rate, focusing on the dynamic phase diagram of the system C 10 E 3 / D 2 O described recently by Oliviero et al [32]; where the authors concluded that a steady-state viscosity could be reached independent of the shear history. The very existence of a history-independent steady state under continuous shear is an important issue and in this paper we present a more detailed investigation of this topic.…”

Section: Introductionmentioning

confidence: 81%

“…In general, the MLV systems are shear thinning and the average MLV radius, R, decreases as the shear rate increases [5,26,32]. For higher surfactant concentrations, the inter-bilayer spacing is independent of the MLV size [33].…”

Section: Introductionmentioning

confidence: 99%

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Reversible size of shear-induced multi-lamellar vesicles

et al. 2005

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IntroductionThe behavior of lamellar phases under shear is a subject that has been receiving a lot of attention in the recent years [1][2][3][4]. In fact, many different shear effects have been reported: transformation from lamellar phases to Multi-lamellar vesicles, MLVs (or ''onions''), in different amphiphilic systems and followed by different techniques [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]; formation of MLVs in presence of submicron-size particles (''stuffed onions'') [21]; changes in lamellar orientation [17,22,23]; formation of intermediates with cylindrical structure between a lamellar and MLV phases [24][25][26]; reduction in lamellar spacing [27]; transitions from MLVs to unilamellar vesicles [28] and ''layering'' effects on onions [8,29]. As a practical application, these MLVs can be used, for instance, to encapsulate chemicals leading to a new kind of controlled micro-reactor [30] or as carriers for oligonucleotide delivery [31].The size distribution of shear-induced multi-lamellar surfactant vesicles depends on the applied shear rate. In general, the MLV systems are shear thinning and the average MLV radius, R, decreases as the shear rate increases [5,26,32]. For higher surfactant concentrations, the inter-bilayer spacing is independent of the MLV size [33]. Hence, a decrease in the MLV size is accompanied by an increase in the MLV number density, N/V, where N is the number of vesicles and V the total volume. The MLVs at higher surfactant concentrations are polyhedral. They fill space with a total volume fraction which is essentially unity [8,34] and N/V is approximately proportional to R )3 . Abstract We have investigated the reversibility in the shear-induced multi-lamellar vesicle (MLV) size during stepwise cycling of the shear rate by employing common rheometry, polarized light microscopy and rheo-optic techniques. We thus address the question whether there is a true MLV steady state, irrespective of history. The system studied, was the nonionic surfactant triethylene glycol decyl ether (C 10 E 3 ) with a concentration of 40 wt.% in D 2 O and a constant temperature of 25°C. It was found that the MLV size varies reversibly with varying shear rate, and hence there exists a true steady state in the presence of shear flow. The experimental observations of reversibility are however restricted to higher shear rates. Because the transformation of the size results from the shear strain, the process is very slow at lower shear rates, where the steady state cannot be reached within a reasonable experimental time.

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Section: Polarized Light Microscopysupporting

confidence: 90%

Section: Introductionmentioning

confidence: 81%

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Reversible size of shear-induced multi-lamellar vesicles

et al. 2005

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“…In order to prepare oriented lamellar phase prior to measurements, the solution was always sheared with a shear rate of 5s -1 at 40°C close to the L α /L 3 phase boundary [7,9]. In the vicinity of the phase boundary, the onion phase is broken down into the planar lamellar phase under shear.…”

Section: Methodsmentioning

confidence: 99%

“…In their model, the shear-thickening behavior would be attributed to the buckling of membranes due to the effective lateral pressure. On the basis of their theory, the shear-induced onion phase formation has been studied from the viewpoint of structural development by the use of scattering and rheological methods [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. Richtering et al found intermediate structure, which can be either coherently buckled lamellar membranes, or multilamellar cylinder structure [9,11].…”

Section: Introductionmentioning

confidence: 99%

Structural rheology of composite onion phase

Fujii

2015

J Biorheol

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We study the shear-induced composite onion phase formation behavior of the nonionic surfactant C 10 E 3 lamellar phases containing colloidal particles. Composite lamellar phase gives rise to the onion phase similar to the free-particle system. Depending on the particle size and concentration, the nonlinear rheology and shear modulus are significantly influenced, while the critical shear rate and onion formation kinetics remains unchanged from those of the free-particle system. Modification of the nonlinear rheology indicates that the colloidal particles assist the onion structure formation so that undulation instability is easily induced by anchoring of membranes on surface of particles. The shear modulus of the composite lamellar and onion phases is reasonably explained by considering the line tension of defects and the effect of polyhedral edge of the onion, respectively.

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