Synergistic structures in lyotropic lamellar gels

Dieterich, Sonja; Prévost, Sylvain; Dargel, Carina; Sottmann, Thomas; Gießelmann, Frank

doi:10.1039/d0sm01473g

Cited by 9 publications

(5 citation statements)

References 82 publications

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“…On the other hand, in the g-N C (3) sample, a turbid gel with thick stacks of ribbons already formed within 20 h, and according to the FFEM images, the structure of these BHPB-6 fibers did not change significantly thereafter. Comparing the obtained fibers with previous attempts to gel lyotropic liquid crystals using different gelators [12,13,16,17], one sees that they were significantly larger. Using the gelators DBS and 12-HOA, one obtains fibers with a width of 8-18 nm in the case of the former [16] and ~27 nm in the case of the latter [12].…”

Section: Freeze Fracture Electron Microscopy Of the Gelled N C Phasesmentioning

confidence: 77%

“…This classification, however, is not applicable in our case where the liquid to be gelled is neither an aqueous solution nor an organic solvent. What we are aiming at is to gel complex fluids in general [12][13][14][15][16][17][18][19][20][21][22][23] and nematic lyotropic liquid crystals in particular [22,23]. The gelation of lyotropic liquid crystals can be influenced by interactions between the surfactants composing the lyotropic liquid crystals and the gelator molecules.…”

Section: Introductionmentioning

confidence: 99%

“…In this case, the presence of the gelator can cause a shift in the phase boundaries of the Gels 2024, 10, 261 2 of 14 lyotropic liquid crystal leading to a phase transition or to a destruction of the lyotropic liquid crystal [12,14,15,21]. If no significant interactions occur between the surfactant and the gelator, the gel network and the lyotropic liquid crystal may form independently of each other, a phenomenon called orthogonal self-assembly [12,13,16,17,24,25]. For the present and the previous study [23], we used the gelator 3,5-bis-(5-hexylcarbamoyl-pentoxy)benzoic acid hexyl ester (BHPB-6), which is a typical organogelator that is insoluble in water [26].…”

Section: Introductionmentioning

confidence: 99%

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Time Dependence of Gel Formation in Lyotropic Nematic Liquid Crystals: From Hours to Weeks

Dombrowski,

Herbst,

Preisig

et al. 2024

Gels

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The combination of lyotropic liquid crystals (LLCs) and low-molecular-weight gelators (LMWGs) for the formation of lyotropic liquid crystal gels (LLC gels) leads to a versatile and complex material combining properties of both parent systems. We gelled the calamitic nematic NC phases of a binary and ternary system using the LMWG 3,5-bis-(5-hexylcarbamoyl-pentoxy)-benzoic acid hexyl ester (BHPB-6). This binary system consists of the surfactant N,N-dimethyl-N-ethyl-1-hexadecylammonium bromide (CDEAB) and water, whereas the ternary system consists of the surfactant N,N,N-trimethyl-N-tetradecylammonium bromide (C14TAB), the cosurfactant n-decanol, and water. Though containing similar surfactants, the gelled NC phases of the binary and ternary systems show differences in their visual and gel properties. The gelled NC phase of the binary system remains clear for several days after preparation, whereas the gelled NC phase of the ternary system turns turbid within 24 h. We investigated the time evolution of the gel strength with oscillation rheology measurements (a) within the first 24 h and (b) up to two weeks after gel formation. The shape of the fibers was investigated over different time scales with freeze fracture electron microscopy (FFEM). We demonstrate that despite their similarities, the two LLC gels also have distinct differences.

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Section: Freeze Fracture Electron Microscopy Of the Gelled N C Phasesmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Time Dependence of Gel Formation in Lyotropic Nematic Liquid Crystals: From Hours to Weeks

Dombrowski,

Herbst,

Preisig

et al. 2024

Gels

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“…Besides experiments for the reversible gelling of hydrogels [44,52], mostly two types of gel-forming agents were used to gel thermotropic LC-phases (see Figure 1). They are presented in Figure 3.…”

Section: Gelation To Prepare Lc-elastomersmentioning

confidence: 99%

Reversible Crosslinking of LC-Materials by Gel-Formation

Zentel

2024

Crystals

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The topic of this review is the physical gelling of liquid crystalline (LC) phases. It allows the combination of order and mobility of the LC-phase with macroscopic stability, which makes it a soft material. Thus, the gelled LCs acquire properties of LC-elastomers without the need for complicated chemistry to allow polymerization and crosslinking. But, instead, an LC-material (either a pure compound or a mixture) can be mixed with a few percent of a gel-forming agent, which self-assembles into long fibers that span the volume of the gel and make it a soft-solid. The use of azo-containing gel-forming agents thereby allows us to make gelation not only thermo-responsive, but also photo-responsive (trans-cis isomerization). This review discusses the micro-morphology of the gelled LCs and their influence on the mechanical properties and the switching in external electric fields. In addition, the potential of reversibility is discussed, which is not only interesting for recycling purposes, but also offers a route to inscribe a complex director pattern into the gelled liquid crystal.

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“…To obtain a stable dispersion of microparticles incorporated in liquid formulations (such as emulsions or microemulsions), thickening with an external polymeric thickener or an organo- , or hydrogelator is often necessary. Most of the polymers (bio- or synthetic) are highly charged, and the mixing of the liquid dispersion with another liquid formulation could induce precipitation.…”

Section: Introductionmentioning

confidence: 99%

New Lyotropic Complex Fluid Structured in Sheets of Ellipsoidal Micelles Solubilizing Fragrance Oils

Tchakalova,

Oliveira,

Figueiredo Neto

2023

ACS Omega

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New lyotropic, fragranced, viscoelastic fluid with a complex structure is obtained from fragranced microemulsions by the addition of a fatty acid. Nonhomogeneous mixing of an appropriate nonionic surfactant, a fatty acid, and a fragrance oil led to the formation of anisotropically shaped and highly oriented micelles in aqueous solution. The nano- and microstructures, and consequently the viscosity, are controlled by the balance of fatty acids used as a cosurfactant and fragrance molecules, which partly behave as a cosurfactant and partly segregate in the micelles of the hydrophilic nonionic surfactant. The transition from isotropic microemulsion to a more structured viscoelastic solution is characterized by X-ray scattering and rheological methods. Considering our X-ray scattering results, we propose a structure composed of planar sheets of ellipsoidal micelles arranged in a lamellar type of stacking. The complex structured, low viscous, transparent fluid is capable of solubilizing a fragrance inside the ellipsoidal micelles, as well as retaining microparticles containing fragrance, without the addition of a polymeric thickener or another gelator. These features allow the creation of a 2-in-1 fragrance-solubilizing liquid product compatible with all types of home and body care consumer products.

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Synergistic structures in lyotropic lamellar gels

Abstract: In this work we present a systematic study on the microstructure of soft materials which combine the anisotropy of lyotropic liquid crystals with the mechanical stability of a physical gel....

Cited by 9 publications

References 82 publications

Time Dependence of Gel Formation in Lyotropic Nematic Liquid Crystals: From Hours to Weeks

Time Dependence of Gel Formation in Lyotropic Nematic Liquid Crystals: From Hours to Weeks

Reversible Crosslinking of LC-Materials by Gel-Formation

New Lyotropic Complex Fluid Structured in Sheets of Ellipsoidal Micelles Solubilizing Fragrance Oils

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