Shear flow of lamellar polymer surfactants

Schmidt, Claudia; Burgemeister, Daniel

doi:10.1007/3-540-47822-1_18

Cited by 4 publications

(1 citation statement)

References 32 publications

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“…This is reminiscent of the D 2 O spectra of lyotropic liquid crystalline polymers and elastomers. 38,39 The most probable explanation is a smaller domain size, which results from a higher defect density. Such a defect structure may allow for a slow exchange (on the time scale of the NMR experiment) of the D 2 O molecules between the domains, which in turn would lead to the observed line broadening (onset of motional narrowing).…”

Section: Visual and 2 H Nmr Phase Studiesmentioning

confidence: 99%

Gelled Lyotropic Liquid Crystals

Laupheimer

Preisig

et al. 2015

Langmuir

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In our previous work we were able to prove that gelled bicontinuous microemulsions are a novel type of orthogonal self-assembled system. The study at hand aims at complementing our previous work by answering the question of whether gelled lyotropic liquid crystals are also orthogonal self-assembled systems. For this purpose we studied the same system, namely, water-n-decane/12-hydroxyoctadecanoic acid (12-HOA)-n-decyl tetraoxyethylene glycol ether (C10E4). The phase boundaries of the nongelled and the gelled lyotropic liquid crystals were determined visually and with (2)H NMR spectroscopy. Oscillating shear measurements revealed that the absolute values of the storage and loss moduli of the gelled liquid crystalline (LC) phases do not differ very much from those of the binary organogel. While both the phase behavior and the rheological properties of the LC phases support the hypothesis that gelled lyotropic liquid crystals are orthogonal self-assembled systems, freeze-fracture electron microscopy (FFEM) seems to indicate an influence of the gel network on the structure of the Lα phase and vice versa.

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Section: Visual and 2 H Nmr Phase Studiesmentioning

confidence: 99%

Gelled Lyotropic Liquid Crystals

Laupheimer

Preisig

et al. 2015

Langmuir

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Rheo-NMR and velocity imaging

Callaghan

2006

Current Opinion in Colloid & Interface Science

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Shear-Induced Structural Transition and Recovery in the Salt-Free Catanionic Surfactant Systems Containing Deoxycholic Acid

Liu

Hao

2011

J. Phys. Chem. B

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Shear-induced structural transition and recovery were studied by freeze-fracture transmission electron microscopy, cryogenic transmission electron microscopy (cryo-TEM), rheological measurements, and the variation of birefringent textures in the system of tetradecyltrimethylammonium hydroxide (TTAOH)/lauric acid (LA)/deoxycholic acid (DeCA)/H(2)O as a function of the molar fraction of DeCA [x = n(DeCA)/(n(DeCA) + n(LA))]. At x = 0.3, giant vesicles and planar lamellar structures were formed before exerting shearing. Shear thickening and large hysteresis loop are observed under shearing, indicating the occurrence of structural transition. Multilamellar and close-packed vesicles were determined by cryo-TEM observations. Exerting further shearing, the elastic properties of the sample were increased due to the strip off of the outer shell of the vesicles and formation of small vesicles. After shearing was stopped, the sample can slowly relax back to the original state. At x = 0.25, lamellar structures, giant vesicles, and small unilamellar vesicles were observed. Cryo-TEM observations show that the multilamellar vesicles can be formed after exerting shearing, and the sample cannot spontaneously recover to the original state. At x = 0.2, vesicles are dominant in the solution, and the aggregates structures are almost the same before and after shearing. Shearing can increase the elastic properties of the sample, which is ascribed to the strip off of the outer shells of the multilamellar vesicles, forming much smaller vesicles in the solution.

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Shear flow of lamellar polymer surfactants

Cited by 4 publications

References 32 publications

Gelled Lyotropic Liquid Crystals

Gelled Lyotropic Liquid Crystals

Rheo-NMR and velocity imaging

Shear-Induced Structural Transition and Recovery in the Salt-Free Catanionic Surfactant Systems Containing Deoxycholic Acid

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