Effect Of Surfactant Chain Length Research Articles

Rheological properties and structures of cationic surfactants and fatty alcohol emulsions: effect of surfactant chain length and concentration

Rheological and optical properties of cetyltrimethylammonium chloride (CTAC)/fatty alcohol (FA), behenyltrimethylammonium chloride (BTAC)/FA and CTAC/FA/hydroxyethyl cellulose (HEC) emulsions have been studied with particular emphases on the effects of FA content, the difference in the chain length of the hydrophobic groups between CTAC and BTAC, and the addition of a water soluble polymer, HEC. The effects of the FA content are to accelerate the structure development during the aging period and to increase the storage modulus, the yield stress, and the zero-shear-rate viscosity in the three emulsion systems investigated. At a low FA content of 2% w/w, lamellar and vesicular aggregates and isolated multilamellar vesicles can be observed in the CTAC/FA and BTAC/FA emulsions, respectively. At a high FA content of 6% w/w or with an excess of FA present, networklike structures and sunflower-like structures form, respectively, instead, inducing a higher entanglement storage modulus and a higher yield stress relative to those emulsions with a low FA content. The effect of adding HEC to the CTAC/FA emulsion is to reduce the entanglement storage modulus and the yield stress, consistent with the optical observation that the presence of the polymer disrupts the formations of lamella and vesicular aggregates and network structures.

Removal of a solid organic soil from a hard surface by glucose-derived surfactants: effect of surfactant chain length, headgroup polymerisation and anomeric configuration

The ability of sugar-derived surfactants to remove a solid organic soil from a hard surface has been investigated using a quartz crystal microbalance (QCM) technique. A matrix of anomerically pure alkyl glucosides and alkyl maltosides, as well as two polydisperse commercial alkylpolyglucoside (APG) surfactant mixtures, were investigated to study the way in which surfactant structure influences hard soil detergency behaviour. As expected, the removal of the hard soil, tristearin, from the gold surface was poor at surfactant concentrations below the critical micelle concentration (CMC) but rose dramatically at higher concentrations. At high concentrations above the CMC, the amount of hard soil ultimately removed was not dependent on the surfactant structure. In contrast, the kinetics of soil removal was dependent on the headgroup degree of polymerisation (DP), alkyl chain length, and anomeric configuration for the matrix of surfactants studied. Alkyl maltoside surfactants removed the hard soil faster than the corresponding alkyl glucoside; an alkyl chain length of ten carbon atoms provided faster soil removal than the octyl or dodecyl counterpart; and at short chain lengths, the α-anomers remove tristearin faster than the corresponding β-anomer.

Stabilization of aqueous foams by polymer/surfactant systems: effect of surfactant chain length

The foaming of mixed polymer/surfactant solutions was investigated as a function of surfactant chain length for the system consisting of the cationic cellulose ether Polymer JR400 and a series of sodium alkyl sulfates (C n H 2 n+1 SO 4Na, n=8, 10 and 12) and sodium decane sulfonate. Foam enhancement by the polymer was observed with all of these surfactants, but the largest effect and best foaming results were found with the shorter chain length surfactants/Polymer JR400 systems, especially the sodium octyl sulfate/Polymer JR400 system. The foaming results correlated with surface viscoelasticity measurements and also with film drainage observations on selected systems.

A Linear Soivation Energy Relationship Study of the Effects of Surfactant Chain Length on the Chemical Interactions Governing Retention and Selectivity in Micellar Electrokinetic Capillary Chromatography Using Sodium Alkyl Sulfate Elution Buffers

ABSTRACT We have used linear solvation energy relationships (LSERs) to study the fundamental chemical interactions responsible for solute retention in micellar electrokinetic capillary chromatography (MEKC). We investigated retention in micellar solutions of sodium dodecyl sulfate (SDS), sodium decyl sulfate (SDecS), and sodium octyl sulfate (SOS). The purpose of the study was to elucidate the effect of surfactant chain length on the solute/micelle interactions that ultimately govern retention and selectivity in MEKC. The nature of the solute/micelle interactions were found to be nearly equivalent in all three systems, implying that the chromatographic selectivity in all three systems will be quite similar. Additionally, the LSERs show that solute size and hydrogen bond basicity play the largest roles in determining solute retention and chromatographic selectivity. Finally, from the LSERs and an analysis of the free energy of transfer of methylene units from water to the micellar phase (δ). we conclude that the solutes reside in the polar, hydrated head group region of the micelles, and not in the nonpolar core. Based on the δ, values for five different homologous solute series, the effect of the solutes' functional groups on the location and orientation of the solutes inside the micelles is briefly discussed.

Micellar Aggregation Numbers - A Fluorescence Study

This two-day laboratory experiment describes how the influence of the hydrocarbon chain length and added salt on the micellar aggregation number of ionic surfactants can be investigated by steady-state fluorescence measurements. Emphasis is put on the necessity to validate the models used to evaluate the data, and examples are given when a given model does not work. For the effect of added salt, sodium dodecylsulphate with and without added sodium chloride was investigated. Both quenchers used, i.e., dodecylpyridinium chloride (DoPyrCl) and 1,3-dicyanobenzene (DCB), yield aggregation numbers in agreement with literature values. For the effect of surfactant chain length, however, the used model failed under certain circumstances. Three alkyltrimethylammonium halides were investigated (CnTA+; n=12, 14, and 16). For the shortest one, DoPyrCl yields a good aggregation number while DCB fails due to electrostatic interactions. For the tetradecyl surfactant, DoPyrCl does not work well, as the difference between the tail-lengths of the quencher and surfactant causes problems in the determination of the amount of micelle-bound quencher. Tetradecylpyridinium chloride circumvents this problem and a consistent aggregation number is obtained. Finally, for the longest surfactant, not even a quencher with a tail of equal length of the surfactant's worked out well, due to the slow diffusion of the quencher in the micellar aggregate.

Simulations of Micelle Self-Assembly in Surfactant Solutions

A simple model of surfactants in aqueous solution is described and molecular dynamics simulations are presented. This model qualitatively reproduces the energy ordering of interactions for surfactants in solution, instead of using the symmetric solvent−solvent and hydrocarbon−hydrocarbon interactions used previously in similar models. The effects of surfactant chain length and concentration are investigated. The results show that the tendency toward micelle formation in the model increases as the chain length is increased and that the type of micelle formed varies with surfactant concentration. Transitions from loose aggregates to spherical micelles to cylindrical micelles are seen as surfactant chain length is increased. A transition from cylindrical micelles to spherical micelles is also seen as surfactant concentration is lowered.

Simulating surfactant self-assembly

This paper briefly reviews simulations of a simple model oil/water/surfactant system. The model describes only the most characteristic elements of oil/water/surfactant mixtures: oil and water do not mix, and a surfactant is an amphiphilic molecule; one side of the molecule likes oil more than water, and the other side likes water more than oil. Molecular dynamics simulations have been performed on this simple model to study the effects of surfactant chain length on the oil/water interfacial tension, the relation between micellar shape and surfactant structure, and the solubilization of an oil droplet in an aqueous micellar solution.

Effect of Alkyl Chain Length on Surfactant Diffusion through a Collagen Film

The effect of surfactant chain length on the diffusion process through a collagenic film was studied. The results obtained showed a linear relationship between the surfactant flow values and the hydrophobic chain length of the molecule.

Quaternary water in oil microemulsions. 1. Effect of alcohol chain length and concentration on droplet size and exchange of material between droplets

Water solubility, electrical conductivity, and time-resolved fluorescence quenching measurements have been performed in water/chlorobenzene/cationic surfactants/1-alcohol water-in-oil (w/o) microemulsions in order to investigate the effect of alcohol chain length and concentration on various properties of these systems: surfactant aggregation number, N, per aggregate; radius, R{sub w}, of the droplet water core; intensity of attractive interdroplet interactions; onset of percolation of electrical conductivity; and rate constant, k{sub e}, for the exchange of material between droplets through collisions with temporary merging. The variations of these properties with the molar concentration ratio {omega} = (water)/(surfactant) for alcohols of increasing chain length are strikingly similar to those found when investigating the effect of surfactant chain length. In particular, N and R{sub w} and the intensity of attractive interactions decrease when the alcohol chain length increases as predicted by current theory of the stability of w/o microemulsions. For a series of microemulsions based on alkyltrimethylammonium bromide surfactants, the water solubility results indicate that the stability of the microemulsions containing short chain alcohols (propanol, butanol) is determined by the attractive interdroplet interactions. The results give support to the mechanism postulated for electrical conductivity above the percolation threshold, namely, motion of counterions through transient water tubes formed inmore » the droplet clusters present in the systems. Finally, it is shown that simple electrical conductivity and water solubility measurements can yield of quantitative information about the investigated microemulsions.« less

Physicochemical properties of aqueous mixtures of tetrabutylammonium bromide and anionic surfactants. 3. Effects of surfactant chain length and salinity

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhysicochemical properties of aqueous mixtures of tetrabutylammonium bromide and anionic surfactants. 3. Effects of surfactant chain length and salinityZhijian. Yu, Xingkang. Zhang, Guangzhi. Xu, and Guoxi. ZhaoCite this: J. Phys. Chem. 1990, 94, 9, 3675–3681Publication Date (Print):May 1, 1990Publication History Published online1 May 2002Published inissue 1 May 1990https://doi.org/10.1021/j100372a059RIGHTS & PERMISSIONSArticle Views314Altmetric-Citations46LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (780 KB) Get e-Alerts

Effect of cationic surfactants on the conformation transition of poly(methacrylic acid)

The interaction between poly(methacrylic acid) and alkyltrimethylammonium bromide, C/sub n/TAB, cationic surfactants has been investigated in aqueous solutions of pH 8, by use of the photophysics of pyrene and its derivatives. Photophysical studies of these fluorescent probes, both steady-state and pulsed laser studies, show that a conformational transition of PMA is induced by C/sub n/TAB. The surfactant induces a coiling up of PMA chains at pH 8, which takes place via a cooperative process. This effect takes place when the concentration of C/sub n/TAB is above a critical aggregate concentration, CAC. The CAC is 1 or 2 orders of magnitude less than the cmc of the corresponding micelle. There is significant effect of surfactant chain length and PMA concentration on the CAC, which provides information on the nature of the CAC and the mechanism of the PMA transition. A model is suggested for the aggregation of PMA-C/sub 10/TAB based on experimental data. Studies show that the aggregate consists of about 100 C/sub 10/TAB molecules and 1 coiled polymer chain.

Kinetic Study on Conformational Changes of Poly(l-lysine) in Sodium Alkyl Sulfate Solutions. Effects of Surfactant Chain Length and Added NaCl

Abstract The conformational changes of poly(l-lysine) (PLL) were observed in alkyl sulfate solutions by a circular dichroic method. PLL forms a β-structure in sodium dodecyl sulfate solution with an apparent first-order rate constant of 3.0×10−2 s−1 (20 °C). In sodium octyl sulfate (SOS) solution, PLL assumes the α-helix within a certain concentration range of the surfactant, above which the β-structure is favored. The rate of coil to β-structure transition slows down with increase in hydrophobic interaction between surfactants and PLL. The presence of sodium ions decreases the rate of coil to α-helix transition by about two orders of magnitude (2.0×10−1 s−1 salt free to 3.0×10−3 s−1 in the presence of 2.0×10−2 mol/dm3 NaCl at 20 °C). These phenomena are explained in terms of a rearrangement process of bound surfactants adjusting for a free energy minimum; a stronger binding force brings about a slower rearrangement rate.