Synergistic Effect of Mixed Surfactant Systems on Foam Behavior and Surface Tension

Foam and surface tension behaviors of different ionic/nonionic surfactant solutions along with their different combinations have been investigated. Among different surfactants, sodium dodecyl sulfate showed the highest foamability over other surfactants. Mixed surfactant systems were always found to have higher foamability than the individual surfactant. It was also noticeable that nonionic surfactants show good foamability when they combine with anionic and cationic surfactants. In the case of mixed surfactant systems, nonionic/cationic surfactant mixtures showed lower surface tension than nonionic/anionic surfactant mixture due to a synergistic effect.     

Spectroscopic and conductometric studies on the interactions of thionine with anionic and nonionic surfactants

In this study, the interaction of thionine, a cationic dye, with anionic [sodium dodecyl sulphate (SDS), lithium dodecyl sulphate (LiDS), and sodium dodecylbenzene sulphonate (SDBS)], nonionic (Tween 20 and Triton X‐100), and binary mixtures of anionic and nonionic surfactants was studied by conductometric and spectrophotometric measurements. The degree of ionisation, the counterion binding parameters, and the equilibrium constants in the premicellar region were obtained from conductivity data. Binding constants of thionine to anionic, nonionic, and mixtures of anionic and nonionic micelles were determined by spectrophotometric measurements. The binding tendency of thionine to anionic micelles followed the order SDBS > SDS > LiDS. The presence of nonionic surfactants increased significantly the binding affinity of thionine to anionic micelles, and the highest binding constant was calculated in the presence of Tween 20. The results obtained from conductometric studies correlated with those obtained from spectroscopic studies. Data concerning dye–surfactant interaction are important for a fundamental understanding of the performance of single and mixed surfactants and for their industrial application.     

Effects of surfactants on the microstructures of electrospun polyacrylonitrile nanofibers and their carbonized analogs

In this study, the influence of surfactants on the processability of electrospun polyacrylonitrile (PAN) nanofibers and their carbonized analogs was investigated. The surfactants employed in this effort are Triton X‐100 (nonionic surfactant, SF‐N), sodium dodecyl sulfate (SDS) (anionic surfactant, SF‐A), and hexadecyltrimethylammonium bromide (HDTMAB) (cationic surfactant, SF‐C). Interactions between electrospun PAN and the surfactants, reflected in effects on as‐spun and carbonized nanofiber morphologies and microstructures, were explored. The results show that uniform nanofibers are obtained when cationic and anionic surfactants (surfactant free and nonionic surfactants) are utilized in the preparation of electrospun PAN. In contrast, a bead‐on‐a‐string morphology results when the aniconic and cationic surfactants are present, and defect structure is enhanced with cationic surfactant addition. Moreover, fiber breakage is observed when the nonionic surfactant Triton X‐100 is employed for electrospinning. After carbonizaition, the PAN polymers were observed to have less ordered structures with addition of any type of surfactant used for electrospinning and the disorder becomes more pronounced when the anionic surfactant is utilized. Owing to the fact that microstructure defects create midband gap states that enable more electrons to be emitted from the fiber, an enhancement of electron emission is observed for PAN electrospun in the presence of the anionic surfactant. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3726–3735, 2013     

Adsorption mechanism of surfactants on nonwoven fabrics

For improved surface properties, nonwoven fabrics of polypropylene and poly(ethylene terephthalate) were treated with several kinds of surfactants, including anionic, cationic, and nonionic types. The adsorption isotherms of the anionic, cationic, and nonionic surfactants on the nonwoven fabrics were different. The adsorption isotherm of the cationic surfactant (dodecyl dimethylbenzyl/ammonium chloride) exhibited a maximum. The adsorption isotherm of the anionic surfactant (sodium dodecylbenzene sulfonate) was in the shape of the fifth Brunauer adsorption isotherm, and that of the nonionic surfactant (alkylphenol/ethylene oxide condensate) was similar to the fourth Brunauer adsorption isotherm. The time of the adsorption equilibrium was constant for the same types of adsorbate and adsorbent, and it was not related to the initial concentration. The specific surface resistance of the nonwoven fabrics decreased substantially after the adsorption of ionic surfactants. The nonwoven fabrics with the surfactants were characterized with scanning electron microscopy and X‐ray photoelectron spectroscopy. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3210–3215, 2003     

Surfactant interactions with P(AM–AA–BPAM) hydrophobically modified polyelectrolytes

The interactions of hydrophobically modified polyelectrolytes poly(acrylamide–sodium acrylic acid–N‐(4‐butyl)phenylacrylamide [P(AM‐AA‐BPAM)] with anionic (sodium dodecyl sulfate), cationic (cetyl trimethylammonium bromide), and nonionic (tetradecyldimethyl‐aminoxid) surfactants were studied via solution rheology, surface tension, and atomic force microscopy measurements. Viscosity measurements indicated that the intermolecular association of the polymer was greatly enhanced by the interaction with the surfactants, especially the oppositely charged surfactants with both a hydrophobic association and an electrostatic attraction. The greatest viscosity increase was realized with the addition of such oppositely charged surfactants. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2664–2671, 2003     

Influence of surfactants on properties of electrochemically synthesized pyrrole/1-dimethylaminopyrrole copolymer

The electrochemical copolymerization of pyrrole (Py) and 1-dimethylaminopyrrole (DMAPy) was successfully carried out in the presence of three different types of surfactant (anionic, cationic and non-ionic) by cyclic voltammetric method. The influence of anionic (sodium dodecylbenzenesulfonate) (NaDBS), cationic (tetradecyltrimethylammonium bromide) and non-ionic poly(ethylene oxide)(10) iso-octylphenyl ether (Tween 20) surfactants on the properties of copolymer was investigated. The copolymer has been characterized by the cyclic voltammetry, fourier transform infrared spectroscopy, UV–Vis spectroscopy, scanning electron microscopy, thermogravimetric analysis and conductivity measurements. The results confirmed that the electrochemical reaction of Py and DMAPy in the presence of surfactants generated copolymers. The type of surfactant had an effect on the structural, morphological, thermal and conductivity properties of the copolymers in different ways. According to the initial decomposition temperatures, the thermal stability of the copolymers improved in the presence of surfactants. Py/DMAPy copolymer synthesized in the presence of anionic surfactant NaDBS had the highest initial decomposition temperature (320 °C). The copolymer prepared using various surfactants exhibited different morphologies. The electrical conductivity of pyrrole/1-dimethylaminopyrrole copolymer (8.39 × 10^?3 Scm^?1) was improved using surfactants, especially with anionic surfactant (3.75 × 10^?2 Scm^?1) due to the incorporation of NaDBS into the PPy polymer chain that resulted in a more compact morphology and reduced size of PPy globules.     

Poly(N‐isopropylacrylamide‐co‐sodium acrylate) hydrogels: Interactions with surfactants

Poly(N‐isopropylacrylamide‐co‐sodium acrylate) [poly(NIPAM‐co‐SA)] hydrogels were modified with three different kind of surfactants (cationic, anionic, and nonionic) to study the effect on the swelling properties. The structural variation of the surfactant‐modified hydrogels was investigated in detail. The interaction between the surfactants and the hydrogel varies and strictly depends on the surfactant type. The variation in thermal stability of the modified surfactant hydrogels was investigated and compared with unmodified hydrogel. Further, the hydrogel swelling/diffusion kinetic parameters were investigated and diffusion of water into hydrogel was found to be of the non‐Fickian transport mechanism. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3423–3430, 2007     

Conducting polymerized high‐internal‐phase emulsion/single‐walled carbon nanotube nanocomposite foams: Effect of the aqueous‐phase surfactant type on the morphology and conductivity

Poly(styrene‐co‐divinylbenzene)/single‐walled carbon nanotubes (SWCNTs) polymerized high‐internal‐phase emulsion (polyHIPE) nanocomposite foams were successfully synthesized with various types of aqueous‐phase surfactants. The effects of anionic, cationic, nonionic, and mixed surfactants on the morphology and electrical conductivity of the resulting nanocomposite foams were investigated. The use of an anionic surfactant, sodium dodecylbenzesulfonate (SDBS), did not completely result in the typical polyHIPE nanocomposite foam microstructure because of the partial instability of the high‐internal‐phase emulsion. The nanocomposite foams synthesized by nonionic surfactants, that is, Pluronic F127 and Triton X‐100, and the cationic/anionic mixture, cetyltrimethylammonium bromide/SDBS, exhibited the proper morphology, but the resulting nanocomposite foams were electrically insulators. Interestingly, the use of a Gemini‐like surfactant, sodium dioctylsulfosuccinate (SDOSS), significantly improved both the typical morphology and electrical properties of the resulting nanocomposite foams because of the probable stronger interactions of SDOSS molecules with SWCNTs. The typical morphology of the nanocomposite foam synthesized with the SDOSS/F127 mixed surfactant was significantly improved, but the electrical conductivity decreased to some extent compared with the SDOSS‐synthesized nanocomposite foams. This behavior was attributed to an increase in the tunneling length of the electrons between adjacent SWCNTs. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43883.     

Nanosized polypyrrole affected by surfactant agitation for emulsion polymerization

Nanosized conductive polypyrrole (PPy) powders were prepared using emulsion polymerization with aid of high speed agitation. Different agitation speeds from 650 to 24,000 rpm were used with different anionic, cationic, and non-ionic surfactants. Then, the effects of the agitation speed and surfactant species were examined in terms of their physical and electrical properties of conductivity and powder size. Prepared PPy nanopowders exhibited high conductivity values of 10 S/cm regions, when sodium dodecylbenzenesulfonate (SDBS) and sodium dodecylsulfate (SDS) were used. The powder dispersion of the resultant PPy was also observed to be dependent on the agitation speed and surfactant type. The morphology shown by SEM and TEM revealed that the anionic SDBS surfactant could effectively disperse into nanosized aggregates of the PPy. The results showed that the combination of the anionic surfactants and high agitation in the emulsion polymerization could produce nanosized PPy powders with higher conductivity.     

Synthesis of polyaniline nanostructures in micellar solutions

Polymerization of aniline nanoparticles was carried out in aqueous micellar solutions of surfactants, including anionic (sodium dodecyl sulfate), nonionic (nonyl phenol ethoxylate), and cationic (cetyltrimethyl ammonium bromide) surfactants. The size and morphology of these synthesized PANI nanoparticles strongly depended on the structure of the surfactants used in the formation of micelles, as shown by transmission electron microscopy. Scanning electron microscopy, Fourier transform infrared spectroscopy, and X‐ray diffraction were used in the characterization of the synthesized PANI nanoparticles. The PANI nanoparticles revealed enhanced conductivity compared to conventional bulk PANI. In addition PANI–poly(methyl methacrylate) (PMMA) nanocomposites were synthesized. The results revealed that the PMMA nanoparticles retarded thermal decomposition and enhanced the conductivities compared with pristine PANI nanoparticles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

阴离子表面活性剂对聚乙二醇水溶液粘度的影响

测定了聚乙二醇（PEG）在十二烷基硫酸钠（SDS）和琥珀酸双-2-乙己酯磺酸钠（AOT）水溶液中的粘度,讨论了SDS和AOT在水溶液中聚集形态的差异对PEG与SDS和AOT相互作用的不同影响,结果表明：PEG-SDS与PEG-AOT体系粘度均明显增加,而PEG-SDS与PEG-AOT体系粘度变化机制不同,根本原因是表面活性剂在高分子溶液中聚集行为不同,SDS分子在PEG链上聚集,形成类胶束,使高分子链带电,表现出聚电解质的粘度行为;PEG链吸附于AOT囊泡,不同PEG链对囊泡的吸附可能造成高分子链更加伸展,PEG特性粘数增大,使溶液粘度上升。     

Mixed micelles of some metal dodecyl sulfates and triton X-100 in aqueous media

Tensiometric studies on several binary surfactant mixtures containing anionic surfactants, viz., metal (lithium, sodium, potassium, copper, cobalt, and magnesium) dodecyl sulfates and a nonionic surfactant (Triton X-100) in water at different mole fractions (0–1) provide critical micelle concentration (CMC) values. The composition of mixed micelles and the interaction parameter, β, evaluated from the CMC data for different systems using Rubingh's theory, are discussed. Marked interaction is observed with monovalent dodecyl sulfates. The influence of counter-ion valence on the formation of mixed micelles was investigated for anionic-nonionic systems, and results indicated that mixed systems with bivalent counter-ions in metal dodecyl sulfate resembled nonionic-nonionic systems where weak/negligible interaction has been reported. Salt addition revealed the weakening of interaction in the mixed systems, which is attributed to the head group charge neutralization and the dehydration of the ethylene oxide units of the nonionic surfactants. A few cloud point and viscosity data are also reported.     

Effect of cationic surfactant addition on the drag reduction behaviour of anionic polymer solutions

Although extensive research work has been carried out on the drag reduction (DR) behaviour of polymers and surfactants alone, little progress has been made on the synergistic effects of combined polymers and surfactants. In this work, the interactions between drag‐reducing anionic polymer (copolymer of acrylamide and sodium acrylate, referred to as PAM) and drag‐reducing cationic surfactant (octadecyltrimethylammonium chloride, OTAC) are studied. Solutions are prepared using both deionised (DI) water and tap water. The measurement of the physical properties such as electrical conductivity and viscosity are used to determine the surfactant–polymer interactions. The addition of surfactant to the polymer solution has a significant effect on the properties of the system. The critical micelle concentration (CMC) of the mixed surfactant–polymer system is found to be different from that of the surfactant alone. With the addition of surfactant to a polymer solution, a substantial decrease in the viscosity occurs. The observed changes in the viscosity of mixed polymer–surfactant system are explained in terms of the changes in the extension of polymeric chains, resulting from polymer–surfactant interactions. The anionic PAM chains tend to collapse upon the addition of cationic OTAC. The pipeline flow behaviour of PAM/OTAC mixtures is found to be consistent with the bench scale results. The DR ability of PAM is reduced upon the addition of OTAC. At low concentrations of PAM, the effect of OTAC on the DR behaviour is more pronounced. The DR behaviour of polymer solutions is strongly influenced by the nature of water (DI or tap). © 2011 Canadian Society for Chemical Engineering     

Influence of polymer on dynamic interfacial tensions of EOR surfactant solutions

The effects of different types of polymers, partially hydrolyzed polyacrylamide (HPAM) and hydrophobically modified polyacrylamide (HMPAM), on dynamic interfacial tensions (IFTs) of surfactant/model oil systems have been investigated by the spinning drop method in this article. Two anionic surfactants, 1,2‐dihexyl‐4‐propylbenzene sulfonate (366), 1,4‐dibutyl‐2‐nonylbenzene sulfonate (494) and an anionic–nonionic surfactant octyl‐[ω‐alkyloxy‐poly(oxyethylene)]yl‐benzene sulfonates (828) with high purity were selected as model surfactants. The influences of polymer concentration on IFT were expounded. It was found that the addition of polymer mostly results in increasing IFT because the interfacial molecular arrangement is modified owing to the interaction between polymer and surfactants. For HPAM, the polymer chains will enter the surfactant adsorption layer to form mixed‐adsorption layer. Therefore, HPAM shows strong effect on surfactant molecules with large size, such as 366. Conversely, surfactants can interact with the hydrophobic blocks of HMPAM and form mixed micelle‐like associations at interface. As a result, HMPAM shows more impact on IFT of 494 due to small steric hindrance for the formation of interfacial associations. This mechanism has been ensured by 828 molecules with two long alkyl chains. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40562.     

Molecular diffusion in ternary poly(vinyl alcohol) solutions

The diffusion kinetics of a molecular probe—rhodamine B—in ternary aqueous solutions containing poly(vinyl alcohol), glycerol, and surfactants was investigated using fluorescence correlation spectroscopy and dynamic light scattering. We show that the diffusion characteristics of rhodamine B in such complex systems is determined by a synergistic effect of molecular crowding and intermolecular interactions between chemical species. The presence of glycerol has no noticeable impact on rhodamine B diffusion at low concentration, but significantly slows down the diffusion of rhodamine B above 3.9% (w/v) due to a dominating steric inhibition effect. Furthermore, introducing surfactants (cationic/nonionic/anionic) to the system results in a decreased diffusion coefficient of the molecular probe. In solutions containing nonionic surfactant, this can be explained by an increased crowding effect. For ternary poly(vinyl alcohol) solutions containing cationic or anionic surfactant, surfactant–polymer and surfactant–rhodamine B interactions alongside the crowding effect of the molecules slow down the overall diffusivity of rhodamine B. The results advance our insight of molecular migration in a broad range of industrial complex formulations that incorporate multiple compounds, and highlight the importance of selecting the appropriate additives and surfactants in formulated products.     

Mixtures of anionic and cationic surfactants with single and twin head groups: Solubilization and adsolubilization of styrene and ethylcyclohexane

Mixtures of anionic and cationic surfactants with single and twin head groups were used to solubilized styrene and ethylcyclohexane into mixed micelles and adsolubilize them into mixed admicelles on silica and alumina surfaces. Two combinations of anionic and cationic surfactants were studied: (i) a single-head anionic surfactant, sodium dodecyl sulfate (SDS), with a twin-head cationic surfactant, pentamethyl-octadecyl-1,3-propane diammonium dichloride (PODD), and (ii) a twin-head anionic surfactant, sodium hexadecyl-diphenyloxide disulfonate (SHDPDS), with a single-head cationic surfactant, dodecylpyridinium chloride (DPCl). Mixtures of SDS/PODD showed solubilization synergism (increased oil solubilization capacity) when mixed at a molar ratio of 1∶3; however, the SHD-PDS/DPCl mixture at a ratio of 3∶1 did not show solubilization enhancement over SHDPDS alone. Adsolubilization studies of SDS/PODD (enriched in PODD) adsorbed on negatively charged silica and SHDPDS/DPCl adsorbed on positively charged alumina showed that while mixtures of anionic and cationic surfactants had little effect on the adsolubilization of styrene, the adsolubilization of ethylcyclohexane was greater in mixed SHPDS/DPCl systems than for SHDPDS alone. Finally, it was concluded that whereas mixing anionic and cationic surfactants with single and double head groups can improve the solubilization capacity of micelles or admicelles, the magnitude of the solubilization enhancement depends on the molecular structure of the surfactant and the ratio of anionic surfactant to cationic surfactant in the micelle or admicelle.     

Polymer‐Cationic Surfactant Interaction: 1. Surface and Physicochemical Properties of Polyvinyl Alcohol (PVA)‐S‐Alkyl Isothiouronium Bromide Surfactant Mixed Systems

Surface properties of polyvinyl alcohol (nonionic polymer) and three synthesized cationic surfactants, namely, S‐alkyl isothiouronium bromide at different mole fractions of 1:9, 3:7, 5:5, 7:3, and 9:1, were investigated. The values of the surface parameters were discussed according to the type of interaction between the cationic surfactant and type of polymer studied. The S‐alkyl isothiouronium bromide surfactant molecules are positively charged molecules, and the PVA chains contain hydroxyl groups that are partially negatively charged centers. The comparison between the surface properties of the individual cationic surfactants and their mixture with PVA polymer showed that the mixed systems have some advantages over the individual cationic surfactants.     

Effect of Inorganic Additives on a Conventional Anionic–Nonionic Mixed Surfactants System in Aqueous Solution

The interaction between an anionic surfactant (sodium dodecyl sulfate) and a nonionic surfactant [polyoxyethylene (9.5) octyl phenyl ether] in aqueous salt solution was investigated using the surface tension method. The critical micelle concentration values were determined for the individual surfactants and their corresponding mixtures. The interaction parameter between the surfactants in the mixed micelles, the activity and activity coefficients in the mixed micelles, and the thermodynamic parameters were calculated using various approaches, viz., Clint, Rubingh, and Maeda models. It was observed that the critical micelle concentration of the mixed surfactants system reveals little deviation from ideality.     

Polyampholytic hydrogels: Poly(N-isopropylacrylamide)-based stimuli-responsive networks with poly(ethyleneimine)

Polyampholytic hydrogels are crosslinked networks composed of positively and negatively charged repeat units that show entirely different properties from their originate polyelectrolyte polymers. Here we report a series of stimuli-responsive polyampholytic hydrogels designed with poly(N-isopropylacrylamide-co-sodium acrylate)/poly(ethyleneimine) [poly(NIPAM-co-SA)/PEI] through the interpenetrating network method. The polyampholytic IPN hydrogel containing 0.5 g PEI showed a higher swelling capacity than the remaining PEI-formulated hydrogels. These gels demonstrated a relatively higher swellability at pH 5 or 6. The interaction of various surfactants and polymer solutions was evaluated at different concentrations. Both the non-ionic (Tween 80) and anionic (sodium dodecyl sulfate, SDS) surfactants promoted their swelling properties, while the cationic (dodecylpyridinium chloride, DPC) surfactant drastically reduced the swelling nature of the polyampholytic semi-IPN hydrogels. Because of more physical attractions between the polyampholytic IPN gels and DPC, it showed a greater thermal stability. The surfactant interactions were eventually studied using scanning electron microscopy. Further, the effect of different salts on the swelling properties of the polyampholytic IPN hydrogels has been demonstrated in detail.     

Mixtures of anionic and cationic surfactants with single and twin head groups: Adsorption and precipitation studies

This research reports on the adsorption and precipitation of mixtures of anionic and cationic surfactants having single and twin head groups. The surfactant mixtures investigated were: (i) a single-head anionic surfactant, sodium dodecyl sulfate (SDS), in a mixture with the twin-head cationic surfactant pentamethyl-octadecyl-1,3-propane diammonium dichloride (PODD)—adsorption was studied on negatively charged silica; and (ii) a twin-head anionic surfactant, sodium hexadecyl-diphenyloxide disulfonate (SHDPDS), and the single-head cationic surfactant dodecylpyridinium chloride (DPCI)—adsorption was studied on positively charged alumina. Whereas the mixed surfactant system of SHDPDS/DPCI showed adsorption on alumina that was comparable to the of SHDPDS alone, the mixed surfactant system of SDS/PODD showed increased adsorption on silica as compared with PODD alone. The adsorption of the SDS/PODD mixture increased as the anionic and cationic system approached an equimolar ratio. Precipitation diagrams for mixtures of single- and twin-head surfactant systems showed smaller precipitation areas than for single-head-only surfactant mixtures. Thus, the combination of single- and double-head surfactants helps reduce the precipitation region and can increase the adsorption levels, although the magnitude of the effect is a function of the specific surfactants used.