Influence of surfactant properties on thermal behavior and sol–gel transitions in surfactant‐HPMC mixtures

Four surfactants, namely, sodium n‐decyl sulfate (SDeS), sodium n‐hexadecyl sulfate (SHS), sodium n‐dodecyl sulfate (SDS), and Triton X‐100, were used as additives to study thermal behavior and sol–gel transformations in dilute aqueous hydroxypropyl methyl cellulose (HPMC)/surfactant mixtures using micro‐differential scanning calorimetry. The influence of anionic surfactant, SDS on the gelation varied with SDS concentration where the sol–gel transition started at a higher temperature. Shape of the thermograms changed from single mode to dual mode at the SDS concentration of 6 mM and higher. SDeS and SHS, however, resulted in “salt‐in” effect of a different magnitude during gelation. Triton X‐100, being a non‐ionic surfactant, showed a minor “salt‐out” effect on the thermo‐gelation process. On the basis of different thermal behavior of anionic and non‐ionic surfactant/HPMC systems, a mechanism is proposed explaining how the chemical structure and electro‐charge of the surfactants affect the polymer/surfactant binding and polymer/polymer aggregation because of hydrophobic interaction during the sol–gel transition. © 2009 Wiley Periodicals, Inc. Journal of Applied Polymer Science, 2009     

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     

Activity and stability ofPenicillium cyclopium lipase in surfactant and detergent solutions

Activity and stability of an alkaline lipase fromPenicillium cyclopium var.album (PG 37) were studied in surfactant and detergent solutions. Three anionic surfactants [Na salts of C₁₂SO₄ ^? (sodium dodecyl sulfate), C₁₂ØSO₃/^? (linear alkyl benzene sulfonate), and C₁₁COO^? (laurate)] and four homologous series of nonionic surfactants of C_12–15 polyoxethylenated fatty alcohols (AEO₃, AEO₅, AEO₇, and AEO₉) were evaluated. At a concentration range of 3.2–40 μM, sodium dodecyl sulfate and laurate stimulated the activity of PG 37 lipase. At concentrations greater than 5.6 μM, linear alkylbenzene sulfonate inhibited PG 37 lipase activity. Nonionic surfactants, AEO₅ and AEO₇, in the concentration range of 0.25–20 mM, enhanced and stabilized the activity of PG 37 lipase. The presence of PG 37 lipase in detergent formulaton improved detergency ～20%. The mechanism of inhibition of the lipolytic activity of PG 37 lipase is proposed to be partly due to the formation of inactive (BR)_n-E complex between the hydrophobic moiety of the surfactants and the surface of the lipase. Conversely, formation of a soluble (RB)_n-E complex between the hydrophilic group of the surfactant and lipase may account for the increased lipolytic activity of PG 37 lipase.     

Advanced synthesis for monodisperse polymer nanoparticles in aqueous media with sub-millimolar surfactants

Highly monodisperse polystyrene nanoparticles with mean diameters of less than 100 nm are synthesized via aqueous emulsion polymerization using an amphoteric initiator (VA-057) in the presence of sub-millimolar concentrations of anionic surfactant. Since the net charge on the initiator is almost zero at neutral pH, the resultant latex particle size is mainly determined by surfactant adsorption. Polymerizations were performed in the presence of a range of anionic surfactants with differing critical micelle concentrations (CMC) by varying the concentrations of surfactant, initiator and monomer, and also the ionic strength. Sodium dodecyl benzene sulfonate (SDBS), sodium hexadecyl sulfate (SHS), and sodium octadecyl sulfate (SOS) have relatively low CMCs and so enable formation of highly monodisperse nanoparticles at relatively low (sub-millimolar) surfactant concentrations, C_S (i.e. below the CMC in each case). Empirically, it was found that the particle number, N_p, and coefficient of variation of the particle size, C_V, were strongly dependent on the C_S/CMC ratio: N_p increased almost in proportion with the square of this ratio, while the C_V exhibited a minimum at approximately C_S/CMC = 0.20. Higher ionic strength reduced the particle size, which is consistent with the above relationship because the addition of salt lowers the CMCs of ionic surfactants. Polymer latex particles produced using such formulations form highly regular, close-packed colloidal arrays.     

Tuning of Cloud Point by the Nature of Surfactant Headgroup: Influence of Counterion and Additives

Work was performed to distinguish the role of sulfonate (–SO₃ ^?) and sulfate (–OSO₃ ^?) with respect to the micellization and clouding phenomenon in ionic surfactant solutions. The clouding phenomenon is a recent addition to the conventional one observed with nonionic surfactants. Three ionic surfactants [sodium dodecylsulfate (SDS), sodium dodecylbenzenesulfonate (SDBS), and sodium dodecylsulfonate (SDSo)] are chosen and the effects of added tetra-n-pentylammonium bromide (TPeAB) and benzyl tributylammonium bromide (BTAC) have been studied on micellization and clouding behaviors in aqueous solution. Based on critical micelle concentration (CMC) and cloud point (CP) measurements, the following order has been observed: SDBS < SDS < SDSo. Though both SDBS and SDSo contain sulfonate groups, they are found at the two ends of the ordering. Therefore, the role of the phenyl ring is also having importance in clouding phenomena. For a typical surfactant, TPeAB was found to be more effective than BTAC. Based on the CP studies, two compositions of SDSo + TPeAB/BTAC were chosen and the effects of different additives (carbohydrate, amino acid, and l-ascorbic acid) on the CP were investigated. Additive may either decrease or increase CP, depending on the structure of the counterion or additive. The present work shows a few novelties: (1) headgroup/counterion dependence of CP and (2) hydrophobicity of counterion/surfactant has an important bearing on the phenomenon. The data can be utilised in improving cloud point extraction methodologies (CPEMs).     

Adsorption of surfactants from water onto raw and HCl-activated clays in fixed beds

The removal of surfactants from water by adsorption onto raw and HCl-activated montmorillonite in fixed beds was studied. Three surfactants hexadecylpyridinium chloride (cationic), sodium dodecyl sulfate (anionic), and Triton X-102 (non-ionic) were selected in the concentration ranges lower than their critical micelle concentrations in fixed bed experiments. It was shown that the adsorption of anionic surfactant onto Ca-montmorillonite (SAz-1) decreased with increasing pH but that of cationic surfactant increased. The adsorption capacity of non-ionic surfactant was maximized at pH 7.0. For given clay, the adsorption capacities of surfactants were strongly pH-dependent. The adsorption capacity and adsorption rate of non-ionic surfactant onto SAz-1 could be largely improved after acid activation of the clay. Such an improvement was due to the fact that the dissolution of Al³⁺ or Fe²⁺ of montmorillonite occurs in acid solution. The calculated breakthrough curves in fixed bed agreed with the measured ones (standard deviation < 6%). The 50% C/C₀ breakthrough time (τ) decreased with increasing liquid flow rate. The effects of flow rate on the adsorption constant and adsorption capacity were also discussed.     

Synthesis and Physicochemical Properties of Alanine-Based Surfactants

The synthesis of a homologous series of alanine-based surfactants, namely sodium salts of n-alkanesulfonamido-2-propanoic acids in which n-alkane is n-dodecane, n-tetradecane, n–hexadecane, and n-octadecane having the formula RSO₂NHCH (CH₃)COO^?Na⁺, is described. The starting materials used were a mixture of secondary positional isomers of n-alkanesulfonyl chlorides obtained by photosulfochlorination reaction using sulfuryl chloride and a catalyst. Surface properties of the aqueous solutions of the synthesized surfactants, including the critical micelle concentration and minimal surface tension δ_min, were determined using surface tension measurements at 25 °C. The surface excess Γ and minimum area per molecule (A _min) where calculated using the Gibbs equation. The foaming power was also determined by the Bartsh method, and the R ₅ parameter was calculated to estimate the stability of the foam formed. The results obtained were compared to those of a commercial surfactant, sodium dodecylsulfate, and a series of synthesized glycine-based surfactants. The results obtained clearly show that the alanine-based surfactants possess good surface properties. The investigations highlight the influence on the surface properties of the addition of a methyl group in the hydrophilic part.     

Novel alkyl methylnaphthalene sulfonate surfactants: A good candidate for enhanced oil recovery

The surface tensions of various surfactant aqueous solution and the dynamic interfacial tensions between the Shengli oil field of China crude oil and the solution of novel surfactants, a series of single-component alkylmethylnaphthalene sulfonates (AMNS) including various the length of alkyl chains (hexyl, octyl, decyl, dodecyl and tetradecyl, developed in our laboratory), were measured. It is found that synthesized surfactants exhibited great capability and efficiency of lowering the solution surface tension. The critical micelle concentrations, CMC were: 6.1–0.018×10⁻³ mol L⁻¹, and the surface tensions at CMC, γ_CMC were: 28.27–35.06 mN m⁻¹. It is also found that the added surfactants are greatly effective in reducing the interfacial tensions and can reduce the tensions of oil–water interface to ultra-low, even 10⁻⁶ mN m⁻¹ at very low surfactant concentration without alkali. The addition of salt, sodium chloride, results in more effectiveness of surfactant in reducing interfacial tension and shows that there exist obviously both synergism and antagonism between the surfactant and inorganic salt. All of the synthesized surfactants, except for hexyl methylnaphthalene sulfonate, can reduce the interfacial tension to ultra-low at an optimum surfactant concentration and salinity. Especially Tetradec-MNS surfactant is most efficient on lowering interfacial tension between oil and water without alkaline and the other additives at a 0.002 mass% of very low surfactant concentration. Both chromatogram separation of flooding and breakage of stratum are avoided effectively, in addition to the less expensive cost for enhanced oil recovery, and therefore it is a good candidate for enhanced oil recovery.     

Influence of surfactants on the electroreduction of oxygen to hydrogen peroxide in acid and alkaline electrolytes

The effect of surfactants on the electroreduction of O₂ to H₂O₂ was investigated by cyclic voltammetry and batch electrolysis on vitreous carbon electrodes. The electrolytes were either 0.1 M Na₂CO₃ or 0.1 M H₂SO₄ at 295 K, under 0.1 MPa O₂. Electrode kinetics and mass transport parameters showed the influence of surfactants on the O₂ electroreduction mechanism. The cationic surfactant (Aliquat 336^®, tricaprylmethylammonium chloride), at mM levels, increased the standard rate constant of O₂ electroreduction to H₂O₂ 15 times in Na₂CO₃ and 1900 times in H₂SO₄, to 1.8 × 10^–6 m s^–1 and 9.9 × 10^–10 m s^–1, respectively. This effect on the reaction rate might be due to an increase of the surface pH, induced by the Aliquat 336^® surface film. The nonionic (Triton X-100) and anionic (sodium dodecyl sulfate) surfactants retarded the O₂ electroreduction, presumably by forming surface structures, which blocked the access of O₂ to the electrode. Ten hour batch electrosynthesis experiments performed at 300 A m^–2 superficial current density, 0.1 MPa O₂, 300 K, on reticulated vitreous carbon (30 ppi), showed that compared to the values obtained in the absence of surfactant, mM concentrations of Aliquat 336^® increased the current efficiency for peroxide from 12% to 61% (0.31 M H₂O₂) in 0.1 M Na₂CO₃ and from 14% to 55% (0.26 M H₂O₂) in 0.1 M H₂SO₄, respectively.     

Emulsion polymerization of styrene: Simulation the effects of mixed ionic and non-ionic surfactant system in the presence of coagulation

A detailed model was developed for emulsion polymerization of styrene in batch reactor to predict the evolution of the product particle size distribution. The effect of binary surfactant systems (ionic/non-ionic surfactants) with different compositions was studied. The zero–one kinetics was employed for the nucleation rate, with the model comprising a set of rigorously developed population balance equations. The modeling incorporated particle formation by both nucleation and coagulation phenomena. The partial differential equations describing the particle population were discretized using finite volume elements. Binary surfactant systems, comprising sodium dodecyl sulfate (SDS) as anionic, and a commercial polyether polyol (Brij35^®) as non-ionic surfactants, were examined with different mass ratios. Increasing non-ionic surfactant mass fraction in binary surfactant system showed the decrease of particle number due to intensifying the coagulation between particles. Broader particle size distributions with greater average particle size were obtained with non-ionic surfactant comparing those obtained with anionic one.     

Effects of surfactants on rheological properties of a dispersed viscoelastic microsphere

The swelling ratio is an important performance for the application of viscoelastic microsphere. The reduction of swelling ratio can affect the particle size. The compatibility between particle size and formation pore can affect the plugging performance and EOR capability. Adsorption characteristics of cationic surfactant cetyltriethylammnonium bromide (CTAB), anionic surfactant petroleum sulfonate applied in GangXi oilfield (GXPS), and nonionic surfactant nonylphenol ether (TX‐10) onto viscoelastic microspheres and the effect of the three types of surfactant on swelling ratio of viscoelastic microspheres were investigated. Effects of surfactants on rheological properties of viscoelastic microspheres were researched in two different modes referring to steady shear and dynamic shear, respectively, using Physica MCR301 Rheometer. The results showed that the interactions between viscoelastic microsphere and surfactants CTAB were electrostatic attraction and hydrophobic association, that the interaction between viscoelastic microsphere and surfactants TX‐10 was just hydrophobic association, and that the interactions between viscoelastic microsphere and GXPS were electrostatic repulsion and hydrophobic association. At the same initial surfactant concentration, all these three types of surfactant could be adsorbed onto the surface of viscoelastic microspheres and reduce its swelling ratio and storage modulus. Because of different amount of adsorption, the extent of reduction order on swelling ratio and storage modulus was CTAB>TX‐10>GXPS. In addition, the yield stress of viscoelastic microspheres which was obtained from modeling the data to Herschel‐Bulkley model decreases with the increase of surfactant adsorption. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42278.     

Synthesis of a biocompatible polymer using siloxane-based surfactants in supercritical carbon dioxide

Poly(N-vinyl-2-pyrrolidone) (PVP) particles were prepared by dispersion polymerization in the presence of 2,2′-azobisisobutyronitrile as the initiator and siloxane-based surfactant in supercritical carbon dioxide (scCO₂). The dispersants used in this study were non-ionic, non-reactive and commercially produced siloxane-based surfactants (Monasil PCA and KF-6017). We investigated the effect of kinds and concentrations of the surfactants, in addition to the reaction temperature and the concentration of the monomer on the particle size and morphology. PVP microspheres were prepared in 0.23–0.74 μm size range with Monasil PCA and 0.71–1.98 μm size range with KF-6017, respectively. The resulting polymer particle of >90% yield was obtained. Particle size slightly increased with the amount of monomer in polymerization with Monasil PCA. In the case of KF-6017 as the surfactant, there was not an obvious variation in particle size with increasing monomer. Particle size of PVP decreased as surfactant concentration increased from 5.0 to 15.0 wt.% basis on concentration of monomer. The narrow particle size distribution (D_n = 0.23 μm and PSD = 1.06) was presented at the high concentration of Monasil PCA (15 wt.% on monomer concentration). As indicated by the reaction temperature and the addition of organic solvent, which affected solubility of monomer, polymer and surfactant in scCO₂, particle size and particle size distribution of PVP varied. PVP particles with Monasil PCA strongly aggregated at 75 °C in contrast to KF-6017 which showed discrete particles at 65 and 70 °C, but particle size distribution was broad. Particle size was slightly reduced with a little amount of hexane, with an inverse relationship of adding hexane reduced the particle size. The amount of the relative residual surfactants on surface of the polymer after extracting with supercritical fluid process (SFE) was measured by using SEM/EDS and EPMA analysis to map out the distribution of silicon element qualitatively. The original polymer particle before the extraction using CO₂ had the high level of silicon element, but the average level of silicon element became low after CO₂ extraction.     

Polycarbonate nanocomposites: Part 2. Degradation and color formation

Polycarbonate nanocomposites were prepared using two different twin screw extruders from a series of organoclays based on sodium montmorillonite, with somewhat high iron content, exchanged with various amine surfactants. It seems that a longer residence time and/or broader residence time distribution are more effective for dispersing the organoclay. The effects of organoclay structure on color formation during melt processing were quantified using colorimeter and UV-Vis spectroscopy techniques. Color formation in the PC nanocomposites depends on the type of organoclay and the type of pristine clay employed. Double bonds in the hydrocarbon tail of the surfactants lead to more darkly colored materials than saturated surfactants. The most severe color was observed when using a surfactant containing hydroxy-ethyl groups and a hydrocarbon tail derived from tallow. Molecular weight degradation of the PC matrix during melt processing produces phenolic end groups which were tracked by UV-Vis spectroscopy. Greater dispersion of the clay generally led to higher reduction in molecular weight due to the increased surface area of clay exposed; however, for color, the situation is far more complex. Hydroxy-ethyl groups and tallow unit on the surfactant lead to more degradation. A selected series of organoclays based on synthetic clay Laponite^® and calcium montmorillonite from Texas (TX-MMT) were also prepared to explore the effects of the clay structure. Laponite^® and TX-MMT produce less color formation in PC nanocomposites than montmorillonite probably due to lower content of iron. Dynamic rheological properties support the trends of molecular weight degradation and dispersion of clay.     

A frequency-dependent surfactant bridge model for the electrorheological behaviors of surfactant-activated suspensions

In surfactant-activated electrorheological (ER) suspensions, the ER response shows linear ER behavior (Τ∞E _o ² at small surfactant concentrations and nonlinear ER behavior (Τ∞E _o ⁿ ,n>2) at large surfactant concentrations. A surfactant bridge model was proposed to explain the nonlinear ER behavior at large surfactant concentrations with some assumptions. The proposed model successfully predicted the qualitative nonlinear ER behavior of surfactant-activated ER suspensions at large surfactant concentrations. Here, the surfactant bridge model is expanded to predict the electric field frequency dependent ER behavior of surfactant-activated ER suspensions. The developed surfactant bridge model can predict both the linear ER behavior at small surfactant concentrations and the nonlinear ER behavior at large surfactant concentrations. Furthermore, this model can predict two different types of the electric field frequency dependent ER behaviors of surfactant-activated ER suspensions, which depend on the amount of surfactants.     

Importance of micellar relaxation time on detergent properties

As we enter the new millennium, manufacturers of laundry detergents would like to provide new products for the twenty-first century. With the goal of achieving new and better performance characteristics, design strategies for research and development should be defined. This paper highlights the importance of micellar relaxation kinetics in processes involved in detergency. Earlier Shah and coworkers showed that the stability of sodium dodecyl sulfate (SDS) micelles plays an important role in various technological processes. The slow relaxation time (τ₂) of SDS micelles, as measured by the pressure-jump technique, was in the range of 10⁻⁴ to 10¹ s, depending on the surfactant concentration. A maximal relaxation time and thus a maximal micellar stability was found at 200 mM SDS (5 s), corresponding to the least-foaming, largest bubble size, longest wetting time of textile, largest emulsion droplet size, and the most rapid solubilization of oil. These results are explained in terms of the flux of surfactant monomers from the bulk to the interface, which determines the dynamic surface tension. More stable micelles lead to less monomer flux and hence to a higher dynamic surface tension. The relaxation time for nonionic surfactants (as measured by the stopped-flow technique) was much longer than for ionic surfactants because of the absence of ionic repulsion between the head groups. The τ₂ was related to dynamic surface-tension experiments. Stability of SDS micelles can be greatly enhanced by the addition of long-chain alcohols or cationic surfactants. In summary, relaxation time data of surfactant solutions enable us to predict the performance of a given surfactant solution. Moreover, results suggest that one can design appropriate micelles with specific stability, or τ₂, by controlling surfactant structure, concentration, and physicochemical conditions, as well as by mixing anionic/cationic or ionic/nonionic surfactants for a desired technological application, e.g., detergency.     

Preparation of nano-TiO2 from TiCl4 by dialysis hydrolysis

The hydrolysis of TiCl₄ was achieved by using a dialysis membrane to make H⁺ and Cl⁻ penetrate out slowly, which produced hydrogel. By this method, no reactant is required and no by-product occurs. The hydrogel was dried by different methods and calcined to obtain nano-TiO₂ powder. The samples were characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), BET surface area and pore size distribution. For comparison, TiCl₄ was also hydrolyzed to prepare nano-TiO₂ by other methods such as heating and adding ammonia. The experiments indicate that hydrolysis and drying have important effects on the properties of product. The hydrogel obtained by dialysis hydrolysis is anatase with a higher phase transformation temperature in calcination and the gel washed with ethanol has better porosity and bigger specific area than the products prepared by other hydrolysis methods and the same washing. In this paper, the drying methods of washing with ethanol and azeotropic distillation with n-butanol were improved by an ensuing rewashing with cyclohexane containing a little of surfactant Span-80 and chemical dehydration with acetic oxide, which further improve the porosity and surface area of nano-TiO₂ powder.     

Itaconic Acid Based Surfactants: I. Synthesis and Characterization of Sodium <Emphasis Type="Italic">n</Emphasis>-Octyl Sulfoitaconate Diester Anionic Surfactant

A novel itaconate-based surfactant, namely sodium n-octyl sulfoitaconate diester (SOSID), has been synthesized from itaconic acid (IA) and n-octanol by sulfonation and esterification reaction processes. The effects of reaction temperature, reaction time, molar ratios of n-octanol to IA and the catalyst dosage on the esterification were investigated. The chemical structure of the surfactants SOSID was characterized by means of LC–MS and confirmed by FT-IR and ¹H NMR spectroscopy. The surface tension γ and the critical micelle concentration (CMC) were determined as 25.02 mN/m and 4.0 × 10^?4 mol/L by using surface tensiometer at 20 °C. Further investigations showed that SOSID possess excellent wetting, emulsifying and lime soap dispersing properties.     

Synthesis and Surface Activities of Amidobetaine Surfactants with Ultra-long Unsaturated Hydrophobic Chains

Recent studies have shown that the surfactants bearing an ultra-long hydrophobic chain (>C18) exhibit unique self-assembly properties. However, their synthesis and surface activities have been less documented. In this work, monounsaturated alkyl dimethyl amidopropyl betaines, UCnDAB (n?=?18, 22, and 24), were prepared by the reaction of the corresponding fatty acids with N,N-dimethyl-1,3-propanediamine, followed by quaternization with sodium choloroacetate of the obtained intermediates. The intermediates and final surfactants were characterized by ¹H NMR and ESI-HRMS, respectively. Krafft temperature (T _K) and surface activities of the surfactants were also examined. It was found that T _K of all these surfactants is lower than 0?°C, and their critical micellar concentration (CMC) is within the range of 10^?3?mmol/L. In addition, the linear relationship between lg CMC and n is still in evidence.     

Electrooxidation of acetaldehyde on platinum-modified Ti/Ru0.3Ti0.7O2 electrodes

In this study, the electrochemical oxidation of acetaldehyde was investigated at activated massive DSA^® electrodes in acid medium, using differential electrochemical mass spectrometry (DEMS) and high-performance liquid chromatography (HPLC). The electrodes were prepared either by platinum electrodeposition or by depositing a highly nanodispersive-supported catalyst (Pt and Pt-Ni) over electrode surfaces with a Ti/Ru_0.3Ti_0.7O₂ nominal composition. Bulk electrolysis shows evidence of CO₂ and acetic acid formation. The electrocatalytic efficiency of the electrode material was also investigated as a function of the amount of catalyst added over the DSA^® electrode surface. The presence of RuO₂-active sites on the DSA^® substrate plays an important role in the reaction overall efficiency. The addition of platinum to DSA^® enhances the oxidation of acetaldehyde to CO₂. The role of the substrate on the direct activation of acetaldehyde oxidation is discussed on the basis of the direct application of the metal nanoparticle catalyst over conductive oxide surface based on Magneli phase (mixture of Ti_nO_2n−1 and other phases) from Ebonex^®.     

Entry in emulsion polymerization using a mixture of sodium polystyrene sulfonate and sodium dodecyl sulfate as the surfactant

A mixture of sodium polystyrene sulfonate (NaPSS) and anionic surfactant, sodium dodecyl sulfate (SDS), was used as the emulsifier in the emulsion polymerization of styrene at 60 °C. The latexes prepared were stable, bearing the better resistance to the addition of electrolyte, and have the larger values in particle size and the higher polymerization rates than those counterparts prepared using SDS only. The NaPSS was prepared by a series of process: a concentrated cyclohexane solution of an anionically polymerized polystyrene (PS) was sulfonated with sulfuric acid at 80 °C, and then neutralized and purified through dialysis. The data of average polymer number per particle (n_p) were found useful in investigating the surfactant content effect on the entry of radicals into particles, where the latex particle size plays an important role.