Unexpected observation of an intermediate hexagonal phase upon fluid-to-gel transition: SDS self-assembly in glycerol

Matthews, Lauren; Stevens, Michaël C.G.; Schweins, Ralf; Bartlett, Paul; Johnson, Andrew J.; Sochon, Robert; Briscoe, Wuge H.

doi:10.1016/j.colcom.2020.100342

Cited by 6 publications

(9 citation statements)

References 46 publications

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“…Previous studies − into the SDS in the glycerol system demonstrated a fibrillar structure on the microscale, with a lamellar nanostructure; the d -spacing of this phase was determined to be d = 5.56 nm. The gel phase is proposed to form as a result of the entanglement of the microfibrils, entrapping free glycerol and increasing the viscosity.…”

Section: Results and Discussionmentioning

confidence: 91%

Unusual Structural Insights Revealed by Rheo–SAXS Studies of Nonaqueous Crystalline Gels

Matthews,

Schmetterer

2024

Langmuir

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Glycerol is a nonaqueous polar solvent and is of interest in many industrial areas due to its beneficial properties, such as green production and biocompatibility. Our previous works have shown the presence of a fibrillar phase on the microscale that consists of lamellar sodium dodecyl sulfate (SDS) crystals containing interstitial glycerol on the nanoscale. The phase is gel-like at room temperature and demonstrates shear-thinning behavior upon application of a shear. Initially, small-angle X-ray scattering coupled with rheology (rheo−SAXS) measurements were performed to elucidate the structural transition of the gel phase under an applied shear, but it became clear that the aging process of the gel has a profound impact on both the gel nanostructure and also the mechanical properties. For younger gels, both the dissolution of SDS crystallites and the alignment of the fibrillar phase were seen. However, in the aged gels, an unexpected foam was formed at shear rates > 700 s −1 . The microscopic structure of the foam phase was imaged using polarizing light microscopy and brightfield and darkfield optical microscopy. The nanostructure of the foam phase was investigated using rheo− SAXS. The foam phase was shown to be stabilized by the presence of SDS crystallites at the air−liquid interface, and the stability of the foam is high with foam persisting even t = 3 months after formation. These results highlight the importance of investigating green nonaqueous media and the gel aging process, both of which are interesting not only on a fundamental level but also for a range of industrial applications, from personal care products and cosmetics to food science.

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Section: Results and Discussionmentioning

confidence: 91%

Unusual Structural Insights Revealed by Rheo–SAXS Studies of Nonaqueous Crystalline Gels

Matthews,

Schmetterer

2024

Langmuir

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“…For instance, in Matthews et al, the decreasing entropy and increasing bulk viscosity in the presence of glycerol were discussed as the main mechanisms for the unexpected formation of a microfibrillar gel in SDS and glycerol mixtures at a critical gelation concentration. 33 Also, Kulmyrzaev et al showed a decrease in protein aggregation rate and gelation that was suggested by the increase in the viscosity. 34 On the other hand, glycerol is known to stabilize the native structure of proteins and peptides, thus changing their hydration and aggregation rate.…”

Section: ■ Results and Discussionmentioning

confidence: 98%

“…In our experiment, the concentration of glycerol was 70%, and the viscosity increased 20-fold at room temperature, so the diffusion of peptides and their aggregation slowed down strongly. For instance, in Matthews et al ., the decreasing entropy and increasing bulk viscosity in the presence of glycerol were discussed as the main mechanisms for the unexpected formation of a microfibrillar gel in SDS and glycerol mixtures at a critical gelation concentration . Also, Kulmyrzaev et al showed a decrease in protein aggregation rate and gelation that was suggested by the increase in the viscosity …”

Section: Resultsmentioning

confidence: 99%

Tunable Self-Assembled Peptide Hydrogel Sensor for Pharma Cold Supply Chain

Tikhonova

Cohen-Gerassi

Arnon

et al. 2022

ACS Appl. Mater. Interfaces

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Defrost sensors are a crucial element for proper functioning of the pharmaceutical cold chain. In this paper, the self-assembled peptide-based hydrogels were used to construct a sensitive defrost sensor for the transportation and storage of medications and biomaterials. The turbidity of the peptide hydrogel was employed as a marker of the temperature regime. The gelation kinetics under different conditions was studied to detect various stages of hydrogel structural transitions aimed at tuning the system properties. The developed sensor can be stored at room temperature for a long period, irreversibly indicates whether the product has been thawed, and can be adjusted to a specific temperature range and detection time.

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“…However, the nanoscopic structure underlying such a macroscopic phase transition was not clear. It has been reported in a related system that, at T > ~ 45 o C, an SDS-in-glycerol gel underwent a lamellar gel-to-fluid transition, with the SDS aggregates transformed from lamellae, via an intermediate hexagonal phase, to cylindrical micelle solutions [18,20].…”

Section: Introductionmentioning

confidence: 99%

Morphological Transformation of SDS Aggregates in a Deep Eutectic Solvent Above the Fracto-eutectogel to Fluid Transition Temperature

Matthews¹,

Se²,

Se³

et al. 2021

Preprint

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Understanding surfactant self-assembly in deep eutectic solvents (DES) is important to their potential use in industrial formulations. We have recently reported the formation of a fracto-eutectogel comprising SDS fractal aggregates at a concentration as low as 1.6 wt% in glyceline (a DES comprising glycerol and choline chloride) at room temperature. The building units of the fractals consisted of multilayers of self-assembled SDS lamellae arranged in a dendritic pattern. Here we report that this fractal phase transitions into a fluid phase above a critical gelation temperature, TCG ~ 45 oC, evident from polarized light microscopy (PLM) observations. Small-angle neutron scattering (SANS) reveals that this phase transition is underpinned by the nanoscopic morphological transformation of the SDS lamellae into cylindrical micelles at T &gt; TGC. Fitting SANS profiles confirms that the morphology of the micelles is SDS-concentration (cSDS) dependent at T &gt; TGC: cylindrical at cSDS &gt; 0.6 wt% and spherical at cSDS = 0.6 wt%. At cSDS &lt; 0.6 wt%, only isotropic scattering was observed in the SANS profiles. Such SDS self-assembly behaviors contrast with those we have previously observed in glycerol, which we attribute to the presence of ions (i.e. choline chloride) in glyceline. Our findings have general implications to surfactant self-assembly in DES, solvents that are rich in hydrogen bonding and ions.

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Unexpected observation of an intermediate hexagonal phase upon fluid-to-gel transition: SDS self-assembly in glycerol

Cited by 6 publications

References 46 publications

Unusual Structural Insights Revealed by Rheo–SAXS Studies of Nonaqueous Crystalline Gels

Unusual Structural Insights Revealed by Rheo–SAXS Studies of Nonaqueous Crystalline Gels

Tunable Self-Assembled Peptide Hydrogel Sensor for Pharma Cold Supply Chain

Morphological Transformation of SDS Aggregates in a Deep Eutectic Solvent Above the Fracto-eutectogel to Fluid Transition Temperature

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