Preparation and surface activity of gelatin derivative surfactants

Surface active gelatin derivative surfactants were formed by covalent attachment of hydrophobic groups to gelatin hydrolyzate molecules. The surface activity was evaluated by surface tension, wetting ability, emulsifying power and foaming properties. It was found that, the modified gelatins are more surface active than the gelatin hydrolyzate. The increase in hydrophobic chain length and the number of attached alkyl chains per gelatin hydrolyzate molecule leads to an increase in the surface activity. The modified gelatins also have high foaming ability and a high emulsifying ability, while the maximal surface activity is obtained by the C₁₂ modified gelatin. The emulsification properties of the gelatin derivative surfactants were also compared to that of sodium dodecyl sulfate (SDS) and polyoxyethylene nonyl phenyl ether (NP-9), both emulsifying ability were equivalent to the C₁₂ modified gelatin.     

Synthesis and performance of a series of dual hydroxyl sulfobetaine surfactants

Five kinds of dual hydroxyl sulfobetaines with different carbon atom numbers in hydrophobic chain were synthesized by using linear saturated alcohol, epichlorohydrin and dimethylamine, and then their structures were characterized by FTIR and ¹H NMR. The stability of all synthesized betaine surfactants in hard water was at level 4, which indicated they had high tolerance on hard water. Their CMC and γ_cmc were lower than the conventional cationic surfactant dodecyltrimethylammonium bromide and anionic surfactant sodium dodecyl, so they had more excellent surface activities. With the chain length increasing from C₈ to C₁₄, the surface activities, emulsifying properties and foaming properties of these betaine surfactants improved because surfactant molecules tightly arranged in the oil-water interface, but there was abnormal phenomenon of surface activity and foam property from C₁₄ to C₁₆ due to overlong hydrophobic chain. According to the results of the experiment, C₁₄SB was the most practical in the five kinds of surfactants, which was potential candidate to enhance oil recovery in oil field. The performances of C₁₄SB were as follows: CMC?=?2.2?×?10^?4?mol/L, γ_cmc?=?30.9 mN/m and the time of bleeding 10?mL water t?=?375?s at 2?g/L the optimum emulsification concentration.     

Investigation of aqueous foam stability containing pigment colorant using polyoxyethylene nonionic surfactant

To improve foam stability in pigment foaming dispersions, a series of fatty alcohol polyoxyethylene ether (CmEOn) with different alkyl chain and ethylene oxide (EO) chain length (m = 12, 14, 16 and n = 5, 7, 9) were used as foam stabilizer to select the most superior structure for stabilizing foam. The effects of CmEOn on surface tension were investigated which revealed that the CMC of CmEOn in the pigment foaming dispersion decreased with the increase of surfactant hydrophobicity or the decrease of hydrophilicity. Compared to the alkyl chain, EO chain length influenced foam more significantly. C₁₄EO₅ in the pigment foaming dispersion showed lowest CMC and equilibrium surface tension. The presence of wormlike micelles and lamellar liquid crystal of SDS and C₁₄EO₅ endowed the C₁₄EO₅ pigment foaming dispersion with highest viscosity which was distinctly different with other CmEOn. C₁₄EO₅ showed the most superior stabilization effects with foam half-life of 172.9 min at 9 wt%. To further analyze the stabilization mechanism of C₁₄EO₅, the foam volume and bubble diameter change were observed with a digital microscope. The results demonstrated that the superior stabilization effects of C₁₄EO₅ were closely related to its high viscosity, which mainly resulted in the decrease of foam drainage and gas permeability. C₁₄EO₅, the optimal CmEOn structure for stabilizing foam, shows excellent foam stabilization capability in pigment foaming dispersions, which is a promising tool to realize pigment foam coloring.     

Decreased surfactant activity coefficients in polymer-surfactant mixtures

The SDS unimer concentration in a series of mixed anionic/non-ionic surfactant solutions comprising sodium dodecylsulphate (SDS) and sugar-based dodecyl bis-N-methyl gluconamides (C₁₂BNMG) have been studied using an anionic surfactant selective electrode, both in the presence and absence of the polyampholyte gelatin. The activity of the SDS has been calculated at the critical micelle concentration (CMC) in the gelatin-free studies and at CMC(1) in the gelatin studies. From the known solution composition, the activity coefficients can be calculated; these show deviations from unity around a solution mole fraction (_SDS) of 0.95 SDS in both cases. The deviation is significantly greater in the presence of gelatin, to an extent that the SDS activity versus _SDS curve exhibits a maximum and a minimum in the region _SDS=0.8–1.0, consistent with the possibility of coexisting micelle types, in agreement with our earlier NMR study (Griffiths et al. (1998) J Chem Soc Chem Comm 1:53).     

评价表面活性剂溶液泡沫性能的方法—真球气泡法北大核心CSCD

通过真球气泡法测定了不同价数和浓度的无机盐体系下十二烷基硫酸钠(SDS)表面活性剂溶液的表面张力和表面扩展黏度;通过Ross-Miles法测定了相应同一溶液的发泡力和泡沫稳定性;结果表明:SDS溶液的表面张力值随着各种无机盐浓度的增加而减小至不变,此时的无机盐浓度作为相对浓度100%来考察时,发现临界胶束浓度(CMC)值与添加盐的种类无关,只随无机盐的相对浓度的增加而减少;即CMC值随着无机盐的相对浓度的增加从不含无机盐时的8.3 mmol/L均收敛至最小值3.0 mmol/L;表面张力值和对应的发泡力值呈负线性关系,由此推断表面张力值可以评价发泡力;表面扩展黏度值和对应的泡沫稳定性值呈正线性关系,由此推断表面扩展黏度可以评价泡沫稳定性;无机盐种类对SDS表面活性剂发泡力和泡沫稳定性的影响力随阳离子价数(Na^(+)、Cu^(2+)、Fe^(3+))增加而增加。     

Synthesis and properties of nonylphenol-substituted dodecyl sulfonate

Nonylphenol-substituted dodecyl sulfonate (C₁₂-NPAS) was synthesized via sulfonation-alkylation-neutralization using 1-dodecene, SO₃, and nonylphenol as raw materials. The properties such as surface tension, interfacial tension (IFT), wettability, foam properties, and salinity tolerance of C₁₂-NPAS were systematically investigated. The results show that the critical micelle concentration (CMC) of C₁₂-NPAS was 0.22?mmol?·?L^?1 and the surface tension at the CMC (γ_CMC) of C₁₂-NPAS was 29.4 mN/m. When compared with the traditional surfactants sodium dodecyl benzene sulfonate (SDBS), sodium dodecyl sulfate (SDS), and linear alkylbenzene sulfonate (LAS), the surface properties of C₁₂-NPAS were found to be superior. The IFT between Daqing crude oil and a weak-base alkaline/surfactant/polymer (ASP) oil flooding system containing 0.1?wt% of C₁₂-NPAS can reach an ultralow level of 2.79?×?10^?3 mN/m, which was lower than that found for the traditional surfactant heavy alkylbenzene sulfonate (HABS). The salinity and hardness tolerance of C₁₂-NPAS were much stronger than those found for conventional surfactants, petroleum sulfonate, and LAS. C₁₂-NPAS also shows improved wetting performance, foamability, and foam stability.     

Interactions between gelatin and sodium dodecyl sulphate: binding isotherm and solution properties

The interaction between sodium dodecyl sulphate (SDS) and gelatin was studied at pH 4.5 and 6.5 where the gelatin is positively charged (i.e.p. 8). At pH 4.5 a SDS/gelatin concentration range was found where gelatin precipitates. At pH 6.5 the SDS-gelatin complex remains soluble although three SDS concentration domains were distinguished where the SDS-gelatin complex had very different affinities for the solvent. Below C₁ the complex was highly surface active but other measurements (viscosity, potentiometry, protons uptake) did not reveal any particular consequence of binding. Between C₁ and C₂ the molecular size decreased (viscosity lowering) upon charge neutralization and collapse about small SDS aggregates (17 SDS molecules per gelatin molecule). Above C₂ a cooperative binding mechanism lead to the formation of SDS aggregates; the complex stretched out and turned strongly hydrophilic (the viscosity increases, low surface activity). At saturation one gelatin molecule bound about 200 SDS molecules. Above the overlap concentration (about 3 wt%) SDS aggregates formed between several gelatin molecules, the viscosity increased continuously with SDS concentration and the binding ratio was lower than in dilute gelatin solutions. A very good correspondence was found between the different analytical data including turbidity, viscosity, surface tension, protons uptake and direct potentiometric SDS binding measurements.     

Foaming in aqueous solutions of zwitterionic surfactant: Effects of oil and salts

This paper reports a study on the stability of foams generated from the aqueous solutions of the zwitterionic surfactant, N-Dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate, in presence of NaCl, CaCl₂ and AlCl₃. The effect of oil (i.e. n-hexane) on foam was also studied. The surface and interfacial tensions were measured. These tensions and the CMC decreased upon salt addition, signifying an increased adsorption of the surfactant molecules at the interface. The quantity of salt required for reducing the surface tension and CMC was in the sequence: NaCl > CaCl₂ > AlCl₃. The salts had a pronounced effect on the foaming characteristics, i.e. they reduced the initial foam volume. The effectiveness of salts in reducing the foam stability followed the sequence: AlCl₃ > CaCl₂ > NaCl. However, the foam collapse rate was reduced in the presence of salt. The presence of oil decreased the foam volume and reduced its stability. The entering, bridging, and spreading coefficients were calculated, which explained the stability of foams in presence of oil.     

Effect of hydrophobically modified SiO2 nanoparticles on the stability of water-based SDS foam

In the present study, SiO₂ nanoparticles were first hydrophobically modified and then added into anionic surfactant sodium dodecyl sulfate (SDS) stabilized water-based foam to improve the foam stability. The foam stability was experimentally evaluated by measuring surface tension, Zeta potential and half-life of the foam. The foam stabilizing mechanism was also studied from a micro perspective by molecular dynamics simulation through analyzing the equilibration configuration and MSD curve of both SDS surfactant and water molecules. The results show that foam exhibits an optimal stability when SiO₂ concentration is 0.35 wt% under a specific surfactant concentration (0.5 wt%) in this work. The addition of SiO₂ nanoparticles with suitable concentration could improve the adsorption between SDS molecules and nanoparticles, thus limiting the movement of SDS and restricting the movement of surrounding water molecules, which is beneficial to enhance the foam stability.     

The Effect of Macromolecules on Foam Stability in Sodium Dodecyl Sulfate/Cetylpyridinium Bromide Mixtures

Abstract

The effects of macromolecules, gelatin, and polyvinylpyrrolidone (PVP), on the properties of foam comprising sodium dodecyl sulfate (SDS) and cetylpyridinium bromide (CPDB) have been studied by measurements of foamability, foam stability, surface tension, and solution specific viscosity. The results indicate that foamability and foam stability are significantly improved when macromolecules are added into mixed systems. Both gelatin and PVP associate with SDS/CPDB surfactants and form aggregates. Electrostatic repulsion and steric stabilization between the two sides of the foam lamellae, due to aggregation, and prevention of drainage in the lamellae, achieved by the long chains of macromolecules are the reasons for increasing foamability and foam stability. The interactions between PVP and surfactants is weaker than those between gelatin and surfactants. The strongest association between macromolecules and surfactants occurs when the molar ratio of SDS/CPDB is 1:1. By comparing PVP with gelatin, the former is favored to increase foamability, and the latter is favored to increase foam stability.     

The Influences of Polymers and Temperature on the Foam Properties of 3‐Dodecylalkoxyl‐2‐hydroxylpropyl Trimethylammonium Chloride

The foam performances of 3‐dodecoxy‐2‐hydroxypropyl trimethylammonium chloride (C₁₂TAC) have been determined in the existence of different relative amount of polymer. The experimental results show that the foaming ability of the mixture systems of the C₁₂TAC/PEG and C₁₂TAC/PVP is stronger than that of the surfactant solutions in the absence of polymer, and with the increase of relative amount of polymer both foaming efficiency and foam stability of the surfactant solutions are evidently enhanced. For the aqueous solution of the surfactant, effect of temperature on foaming properties has also been examined. The results show that both the foaming ability and stability of the foams of the surfactant solutions are highest (or strongest) at 30°C.     

Synergistic improvement of foam stability with SiO2 nanoparticles (SiO2-NPs) and different surfactants

Foam fluids are widely used in petroleum engineering, but long-standing foam stability problems have limited the effectiveness of their use. The study explores the synergistic effects and influencing factors of SiO₂ nanoparticles (SiO₂-NPs) with different wettability properties and three different surfactants. The paper investigates the foaming performance of different types of surfactants and analyzes and compares the stability of foam after adding hydrophilic and hydrophobic SiO₂-NPs from macroscopic as well as microscopic perspectives, and the effects of temperature and inorganic salts on the stability of mixed solutions. The experimental results show that: 1) hydrophilic nanoparticles can significantly enhance the foam stability of amphoteric surfactants, with a small increase in the foam stability of anionic and cationic surfactants; 2) The concentration of nanoparticles did not have a significant effect on the stability of the cationic surfactants and this conclusion was verified in the experimental results of the surface tension measured below;3) The cationic surfactants showed better temperature resistance at temperatures of 50–90 °C. Both amphoteric surfactant solutions with the addition of hydrophilic SiO₂-NPs or hydrophobic SiO₂-NPs significantly improved the temperature resistance of the foam at high temperatures. The anionic surfactant solution with hydrophobic SiO₂-NPs did not enhance the solution temperature resistance; 4) The surface tension of the surfactant solution gradually increases with increasing concentration of hydrophilic or hydrophobic SiO₂-NPs and then levels off; 5) the hydrophilic SiO₂-NPs had a significant effect on the salt tolerance of the anionic and amphoteric surfactant solutions. The salt tolerance of cationic surfactant solutions with hydrophobic SiO₂-NPs was better than that of surfactants with hydrophilic SiO₂-NPs.     

The Impact of Foaming Effect on the Physical and Mechanical Properties of Foam Glasses with Molecular-Level Insights

Foaming effect strongly impacts the physical and mechanical properties of foam glass materials, but an understanding of its mechanism especially at the molecular level is still limited. In this study, the foaming effects of dextrin, a mixture of dextrin and carbon, and different carbon allotropes are investigated with respect to surface morphology as well as physical and mechanical properties, in which 1 wt.% carbon black is identified as an optimal choice for a well-balanced material property. More importantly, the different foaming effects are elucidated by all-atomistic molecular dynamics simulations with molecular-level insights into the structure–property relationships. The results show that smaller pores and more uniform pore structure benefit the mechanical properties of the foam glass samples. The foam glass samples show excellent chemical and thermal stability with 1 wt.% carbon as the foaming agent. Furthermore, the foaming effects of CaSO₄ and Na₂HPO₄ are investigated, which both create more uniform pore structures. This work may inspire more systematic approaches to control foaming effect for customized engineering needs by establishing molecular-level structure–property–process relationships, thereby, leading to efficient production of foam glass materials with desired foaming effects.     

Gemini型磺基琥珀酸酯钠表面活性剂的结构与性能的关系

以不同的醇为原料,合成了不同的Gemini型磺基琥珀酸酯钠阴离子表面活性剂,对它们的表面化学性能和应用性能进行了测定,并将其性质与其结构的关系进行关联。结果表明:其活性高于相应单基表面活性剂,且联结基、憎水链长度对其活性有影响。联结基长度增加,产物的临界胶束浓度(CMC)降低,对应的表面张力增加,其乳化性、起泡性、稳泡性、渗透力降低,增溶性提高;憎水链长度增加,CMC降低,对应的表面张力先减后增,其乳化性、稳泡性、增溶性提高,起泡性先增后减,渗透力减弱。     

Surface and volume properties of dodecylethyldimethylammonium bromide and benzyldimethyldodecylammonium bromide: II. Volumetric properties of dodecylethyldimethylammonium bromide and benzyldimethyldodecylammonium bromide

Density measurements were carried out for aqueous solutions of two cationic surfactants: dodecylethyldimethylammonium bromide (C₁₂(EDMAB)) and benzyldimethyldodecylammonium bromide (BDDAB). On the basis of the obtained results of the measurements the CMC and partial molar volumes of the surfactants studied were also determined. The obtained CMC values were also analyzed with those accounted on the basis of the surface tension data from the previous paper [J. Harkot, B. Jańczuk, J. Colloid Interface Sci. (2008), submitted for publication]. The values of CMC determined from the surface tension and density measurements for C₁₂(EDMAB) are equal to 9.9×10⁻³ and 1.5×10⁻² M and for BDDAB to 5.25×10⁻³ and 5.3×10⁻³ M, respectively. These obtained values are very similar. However, in the literature it is difficult to find the CMC values for C₁₂(EDMAB) and BDDAB determined by these two methods used by us—especially from the density measurements for BDDAB and surface tension measurements for C₁₂(EDMAB). In the case of the apparent molar volumes of C₁₂(EDMAB) there is a good agreement between the values obtained by us and those found in the literature. The CMC values for C₁₂(EDMAB) and BDDAB were also determined on the basis of their surface tension and free energy of electrostatic interactions between the polar heads of these surfactants and compared with those obtained from the surface tension and density measurements. It was found that the theoretically obtained CMC values were close to those determined from the density and surface tension data for the C₁₂(EDMAB) and that the ratios of the CMC values of the surfactants to their concentration at which the water surface tension decreased by about 20 mN/m proved that the presence of the aryl group in the BDDAB head instead of the methyl group caused that its micellization process was more inhibited in relation to its adsorption at air–water interface than that of C₁₂(EDMAB).     

Interfacial Properties of Hydrophobically Modified Biomolecules: Fundamental Aspects and Applications

This review describes the interfacial behavior of biomolecules, which were converted to more hydrophobic derivatives by covalent attachment of hydrophobic chains. The molecules presented are proteins (glucose oxidase, immunoglobulin G, gelatin, ovalbumin) and polysaccharides (carboxymethylcellulose, pullulan). In general, it was found that such hydrophobically modified biomolecules have enhanced surface activity and ability to penetrate into phospholipid monolayers. In addition, it has been demonstrated, that such molecules can be used as efficient emulsifiers and foaming agents, and in unique biomedical application based on combining the surface activity and recognition ability.

     

Colloid-chemical properties of 1,1-dimethyl-1-alkylhydrazinium chlorides

The colloid-chemical properties [surface tension, surface activity, and critical micellization concentration (CMC)] of aqueous 1,1-dimethyl-1-alkyl(R)hydrazinium chlorides (R = C₁₀H₂₁–C₁₈H₃₇) were studied.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 11, 2004, pp. 1861–1864.Original Russian Text Copyright © 2004 by Shcherban, Radushev, Nasretdinova, Teterina, Bubyakina.     

Properties of Interfacial Layers in Multicomponent Systems Containing Gelatin

The review is devoted to the analysis of the effect of the addition of various surfactants on the composition, structure, and the properties of the interfacial adsorption layers (IALs) formed at equilibrium in the aqueous gelatin solution–hydrocarbon system. Associates of variable compositions that are determined by the component ratio and the concentration of added surfactant are formed due to the interaction between gelatin and surfactant. The formation of associates is equivalent to the modification of gelatin. The properties of the IALs of modified gelatins are discussed on the basis of our own results and published data on the interfacial tension, the mass accumulation of surface-active components at the interfaces during the IAL formation, the IAL rheological properties and the stability of emulsion films varied with the conditions of IAL formation (the nature of low-molecular-weight surfactant, component concentrations, pH of aqueous phase, and temperature). It was concluded that modified gelatins can be considered as new surfactants governing the dynamics of the formation and fracture mechanism of the IALs and the stability of emulsion films. The properties of the IALs of modified gelatins are compared with those of IALs formed by gelatin and low-molecular-weight surfactants under the conditions when associates are formed directly at the interface due to the use of oil-soluble surfactants.     

Rheological Properties of the Interfacial Layers of Hydrophobized Gelatins

Rheological properties of the interfacial layers of gelatins chemically modified with N-hydroxysuccinimide ester of caprylic acid (the degree of modification is 10, 30, and 85%) are studied. Interfacial layers are spontaneously formed at the aqueous gelatin solution–toluene interface. Rheological characteristics (yield strength, modulus of elastic deformation, Schwedoff and Bingham viscosities) increase in proportion to the degree of modification (hydrophobization) of gelatin.     

Influence of alkyl chain length of alpha olefin sulfonates on surface and interfacial properties

Alpha olefin sulfonates (AOS) with various alkyl chain lengths have been used to investigate the influence of alkyl chain length on the interfacial properties at air–water, liquid paraffin–water, and parafilm–water interfaces. It was found that the critical micelle concentration decreased with increasing alkyl chain length, while the efficiency of reducing surface tension was inverse relationship with alkyl chain length. The diffusion coefficient obviously reduced with an increase of surfactant concentration and alkyl chain length. The C_14-16AOS shows better wettability and emulsification than C_16-18AOS and C_20-24AOS. For foaming properties, the foamability and foam stability dramatically decreased with increasing alkyl chain length.