scholarly journals Interfacial and Foaming Properties of Tailor-Made Glycolipids—Influence of the Hydrophilic Head Group and Functional Groups in the Hydrophobic Tail

Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3797
Author(s):  
Rebecca Hollenbach ◽  
Annika Ricarda Völp ◽  
Ludwig Höfert ◽  
Jens Rudat ◽  
Katrin Ochsenreither ◽  
...  

Glycolipids are a class of biodegradable surfactants less harmful to the environment than petrochemically derived surfactants. Here we discuss interfacial properties, foam stability, characterized in terms of transient foam height, gas volume fraction and bubble diameter as well as texture of seven enzymatically synthesized surfactants for the first time. Glycolipids consisting of different head groups, namely glucose, sorbitol, glucuronic acid and sorbose, combined with different C10 acyl chains, namely decanoate, dec-9-enoate and 4-methyl-nonanoate are compared. Equilibrium interfacial tension values vary between 24.3 and 29.6 mN/m, critical micelle concentration varies between 0.7 and 3.0 mM. In both cases highest values were found for the surfactants with unsaturated or branched tail groups. Interfacial elasticity and viscosity, however, were significantly reduced in these cases. Head and tail group both affect foam stability. Foams from glycolipids with sorbose and glucuronic acid derived head groups showed higher stability than those from surfactants with glucose head group, sorbitol provided lowest foam stability. We attribute this to different head group hydration also showing up in the time to reach equilibrium interfacial adsorption. Unsaturated tail groups reduced whereas branching enhanced foam stability compared to the systems with linear, saturated tail. Moreover, the tail group strongly influences foam texture. Glycolipids with unsaturated tail groups produced foams quickly collapsing even at smallest shear loads, whereas the branched tail group yielded a higher modulus than the linear tails. Normalized shear moduli for the systems with different head groups varied in a narrow range, with the highest value found for decylglucuronate.

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Shixin Dai ◽  
Yufei Gong ◽  
Feng Wang ◽  
Pan Hu

Hydraulic fracturing is an important technology for the development of unconventional resources, while the foam fracturing plays an essential role for the oil recovery in hydraulic fracturing. To further explore the anion effect of quaternary ammonium cationic surfactants on their relative performances, four fatty acid surfactants were prepared (cetyltrimethylammonium acetate (CTAAC), cetyltrimethylammonium butyrate (CTABU), cetyltrimethylammonium hexanoate (CTAHE), and cetyltrimethylammonium caprylate (CTACA)). The effect of anions on surface tension and foaming properties were discussed, and the emulsion stability was also investigated. The experimental results were presented that the CTAAC possesses the highest surface activities compared with other members in the prepared surfactants. The critical micelle concentration (CMC) and surface tension at the CMC (γCMC) increase as increasing methylene segments in the anions, the maximum surface excess concentration (Γmax), and minimum area per molecule (Amin) present an opposite trend with the increase of methylene segments. The CTAAC exhibits the best performances on foamability and foam stability than other synthesized surfactants at 70°C; the initial foam height (H0) and the foam height ratio (R3) at 0 min and 3 min are 34.9 cm and 52.9%, respectively; this is due to the lowest surface tension and shortest methylene segments. In addition, the emulsion stability was shown to follow the order of CTAAC>CTABU>CTAHE>CTACA.


2012 ◽  
Vol 710 ◽  
pp. 383-388
Author(s):  
N.V. Ravi Kumar ◽  
Hina Gokhale ◽  
Amol A. Gokhale

Metallic foams find specialised applications in industry due to their unique properties such as ultra light weight and high impact energy absorption. When ceramic particles (e.g. SiC, Al2O3) are present, metal matrix composite (MMC) foams can be fabricated. Further it is known theoretically that foam strength is proportional to strength of foam material, and also it has been established that metal matrix composites exhibit better strength vis-à-vis their matrix metal. Accordingly, the present work is undertaken to study the processing of composite foams. Al-Si-Mg/SiCP foams were successfully prepared via liquid metallurgy processing using TiH2. The role of particle size, volume fraction (5 to 20 vol. %), and temperature (640 and 670°C) on foaming tendency were explored using the design of experiments approach. Liquid foams with reasonably good expansions could be achieved for all the combinations of particle size, volume %, and foaming temperature. Temperature has a dominant effect on foam collapse (decay) during solidification, irrespective of the particle size and vol. %. For foams processed at 640°C, the cell size variation is marginal along the foam height, except at the top portion which has finer cells. The evolution of foam, and the role of SiC on foam stability are discussed based on macro and microstructural results.


Soft Matter ◽  
2021 ◽  
Author(s):  
D. Zeb Rocklin ◽  
Lilian C Hsiao ◽  
Megan E Szakasits ◽  
Michael J Solomon ◽  
Xiaoming Mao

Rheological measurements of model colloidal gels reveal that large variations in the shear moduli as colloidal volume-fraction changes are not reflected by simple structural parameters such as the coordination number,...


2021 ◽  
Vol 22 (12) ◽  
pp. 6592
Author(s):  
Artur Seweryn ◽  
Tomasz Wasilewski ◽  
Anita Bocho-Janiszewska

The article shows that the type and concentration of inorganic salt can be translated into the structure of the bulk phase and the performance properties of ecological all-purpose cleaners (APC). A base APC formulation was developed. Thereafter, two types of salt (sodium chloride and magnesium chloride) were added at various concentrations to obtain different structures in the bulk phase. The salt addition resulted in the formation of spherical micelles and—upon addition of more electrolyte—of aggregates having a lamellar structure. The formulations had constant viscosities (ab. 500 mPa·s), comparable to those of commercial products. Essential physical-chemical and performance properties of the four formulations varying in salt types and concentrations were evaluated. It was found that the addition of magnesium salt resulted in more favorable characteristics due to the surface activity of the formulations, which translated into adequately high wettability of the investigated hydrophobic surfaces, and their ability to emulsify fat. A decreasing relationship was observed in foaming properties: higher salt concentrations lead to worse foaming properties and foam stability of the solutions. For the magnesium chloride composition, the effect was significantly more pronounced, as compared to the sodium chloride-based formulations. As far as safety of use is concerned, the formulations in which magnesium salt was used caused a much lesser irritation compared with the other investigated formulations. The zein value was observed to decrease with increasing concentrations of the given type of salt in the composition.


Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 116-125
Author(s):  
Yi-Fan Li ◽  
Amit Ghosh ◽  
Pronay Kumar Biswas ◽  
Suchismita Saha ◽  
Michael Schmittel

Three distinct four-component supramolecular nanorotors were prepared, using, for the first time, bipyridine instead of phenanthroline stations in the stator. Following our established self-sorting protocol to multicomponent nanodevices, the nanorotors were self-assembled by mixing the stator, rotators with various pyridine head groups, copper(I) ions and 1,4-diazabicyclo[2.2.2]octane (DABCO). Whereas the exchange of a phenanthroline vs. a bipyridine station did not entail significant changes in the rotational exchange frequency, the para-substituents at the pyridine head group of the rotator had drastic consequences on the speed: 4-OMe (k298 = 35 kHz), 4-H (k298 = 77 kHz) and 4-NO2 (k298 = 843 kHz). The exchange frequency (log k) showed an excellent linear correlation with both the Hammett substituent constants and log K of the copper(I)–ligand interaction, proving that rotator–copper(I) bond cleavage is the key determining factor in the rate-determining step.


2013 ◽  
Vol 3 (1) ◽  
pp. 87 ◽  
Author(s):  
Quirino Dawa ◽  
Yufei Hua ◽  
Moses Vernonxious Madalitso Chamba ◽  
Kingsley George Masamba ◽  
Caimeng Zhang

<p>Understanding how foaming properties of proteins are affected by factors such as pH, salt concentration and temperature is essential in predicting their performance and utilisation. In this study, the effects of pH and salt concentration were studied on the foaming properties of pumpkin seed protein isolate (PSPI) and PSPI- xanthan (XG)/Arabic (GA) gum blends. The foaming properties of the PSPI-GA/XG blends were also compared with egg white. Foam stability (FS) was significantly affected by pH with PSPI: GA (25:4) and PSPI: XG (25:1) having a significantly higher stability at pH 2 with the lowest foam stability at pH 4. Sodium chloride (0.2-1.0 M) did not significantly affect foaming properties although PSPI: GA (25:4) had the highest FC (89.33 ± 3.24%) and FS (76.83 ± 1.53 min) at 0.2 M sodium chloride concentration. The foaming capacity (FC) of PSPI: GA (25:4) blend (128.00 ± 0.91%) was significantly higher (<em>p </em><em>&lt; </em>0<em>.</em>05) than that of egg white (74.00 ± 1.33%) but its FS was significantly lower. It was further revealed that the FC of egg white (74.00 ± 1.33%) was comparable to the PSPI:XG (25:1) blend (74.00 ± 1.46%) but the FS for egg white (480.00 ± 2.67 min) was significantly higher (<em>p </em><em>&lt; </em>0<em>.</em>05) than the FS (116.21 ± 0.86 min) of PSPI:XG (25:1). The foaming properties of PSPI and PSPI-xanthan (XG)/Arabic (GA) blends were significantly affected by pH. Optimum foaming properties, PSPI:XG (25:1) and PSPI:GA (25:4) were observed at pH 2 and heat treatment temperature of 80 ºC.</p>


2020 ◽  
Vol 27 (1) ◽  
pp. 3-12
Author(s):  
Prasanth KS Pillai ◽  
Yulinglong Ouyang ◽  
Andrea K Stone ◽  
Michael T Nickerson

This research examines changes to the functional (solubility, emulsifying and foaming) properties of pea protein isolate when complexed with commercial citrus pectin of different structural attributes. Specifically, a high methoxy (P90; degree of esterification: 90.0%; degree of blockiness: 64.5%; galacturonic acid content 11.4%) and low methoxy (P29; degree of esterification: 28.6%; degree of blockiness: 31.1%; galacturonic acid: 70%) pectin at their optimum mixing ratios with pea protein isolate (4:1 pea protein isolate to P90; 10:1 pea protein isolate to P29) were assessed at the pHs associated with critical structure forming events during the complexation process (soluble complexation (pHc), pH 6.7 and 6.1; insoluble complex formation (pHϕ1), pH 4.0 and 5.0; maximum complexation (pHopt), pH 3.5 and 3.8; dissolution of complexes, pH 2.4 and 2.1; for admixtures of pea protein isolate–P90 and pea protein isolate–P29, respectively). Pea protein isolate solubility was improved from 41 to 73% by the presence of P90 at pH 6.0 and was also moderately increased at pH 4.0 and pH 5.0 by P90 and P29, respectively. The emulsion stability of both pea protein isolate–pectin complexes was higher than the homogeneous pea protein isolate at all critical pHs except pHopt as well as pHc for pea protein isolate–P29 only. P90, with the higher level blockiness and esterification, displayed better foaming properties at the maximal complexation pH when complexed with pea protein isolate than pea protein isolate–P29 or pea protein isolate alone. However at pHϕ2, pea protein isolate–P29 admixtures produced foams with 100% stability, increasing pea protein isolate foam stability by 85%. The enhanced functionality of pea protein isolate–pectin complexes based on the type of pectin used at critical pHs indicates they may be useful biopolymer ingredients in plant protein applications.


2019 ◽  
Vol 29 (1) ◽  
pp. 58-68 ◽  
Author(s):  
Graeme Gillies

Abstract The rheological and structural properties of cheese govern many physical processes associated with cheese such as slumping, slicing and melting. To date there is no quantitative model that predicts shear modulus, viscosity or any other rheological property across the entire range of cheeses; only empirical fits that interpolate existing data. A lack of a comprehensive model is in part due to the many variables that can affect rheology such as salt, pH, calcium levels, protein to moisture ratio, age and temperature. By modelling the casein matrix as a series core-shell nano particles assembled from calcium and protein these variables can be reduced onto a simpler two-dimensional format consisting of attraction and equivalent hard sphere volume fraction. Approximating the interaction between core-shell nano particles with a Mie potential enables numerical predictions of shear moduli. More qualitatively, this two-dimensional picture can be applied quite broadly and captures the viscoelastic behaviour of soft and hard cheeses as well as their melting phenomena.


2011 ◽  
Vol 332-334 ◽  
pp. 1515-1519 ◽  
Author(s):  
Ke Li ◽  
Jian Fei Zhang ◽  
Qiu Jin Li

Foam dyeing and finishing is a novel approach for textile processing, which can save energy and reduce the quantity of waster water. Frother plays an important role in foam dyeing and finishing systems. In this paper, the foaming properties of SDS were investigated for the purpose of application of foaming systems in fabric dyeing and finishing. The influence of SDS on foam properties was studied by measuring foamability, foam stability, equilibrium and dynamic surface tension, surface viscosity bubble size and bubble uniformity. At the same time, the relationship between foam apparent performance and microcosmic mechanism was also analyzed. The research will benefits the future study on the application of foam technique to the field of textile.


Processes ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. 908 ◽  
Author(s):  
Muhammad Shahzad Kamal ◽  
Syed Muhammad Shakil Hussain ◽  
Lionel Talley Fogang

Long-term thermal stability of surfactants under harsh reservoir conditions is one of the main challenges for surfactant injection. Most of the commercially available surfactants thermally degrade or precipitate when exposed to high-temperature and high-salinity conditions. In this work, we designed and synthesized three novel betaine-based polyoxyethylene zwitterionic surfactants containing different head groups (carboxybetaine, sulfobetaine, and hydroxysulfobetaine) and bearing an unsaturated tail. The impact of the surfactant head group on the long-term thermal stability, foam stability, and surfactant–polymer interactions were examined. The thermal stability of the surfactants was assessed by monitoring the structural changes when exposed at high temperature (90 °C) for three months using 1H-NMR, 13C-NMR, and FTIR analysis. All surfactants were found thermally stable regardless of the headgroup and no structural changes were evidenced. The surfactant–polymer interactions were dominant in deionized water. However, in seawater, the surfactant addition had no effect on the rheological properties. Similarly, changing the headgroup of polyoxyethylene zwitterionic surfactants had no major effect on the foamability and foam stability. The findings of the present study reveal that the betaine-based polyoxyethylene zwitterionic surfactant can be a good choice for enhanced oil recovery application and the nature of the headgroup has no major impact on the thermal, rheological, and foaming properties of the surfactant in typical harsh reservoir conditions (high salinity, high temperature).


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