Molecular Dynamic Simulation on the Absorbing Process of Isolating and Coating of α-olefin Drag Reducing Polymer

The absorbing process in isolating and coating process of α-olefin drag reducing polymer was studied by molecular dynamic simulation method, on basis of coating theory of α-olefin drag reducing polymer particles with polyurethane as coating material. The distributions of sodium laurate, sodium dodecyl sulfate, and sodium dodecyl benzene sulfonate on the surface of α-olefin drag reducing polymer particles were almost the same, but the bending degrees of them were obviously different. The bending degree of SLA molecules was greater than those of the other two surfactant molecules. Simulation results of absorbing and accu-mulating structure showed that, though hydrophobic properties of surfactant molecules were almost the same, water density around long chain sulfonate sodium was bigger than that around alkyl sulfate sodium. This property goes against useful absorbing and accumulating on the surface of α-olefin drag reducing polymer particles; simulation results of interactions of different surfactant and multiple hydroxyl compounds on surface of particles showed that, interactions of different surfactant and one kind of multiple hydroxyl compound were similar to those of one kind of surfactant and different multiple hydroxyl compounds. These two contrast types of interactions also exhibited the differences of absorbing distribution and closing degrees to surface of particles. The sequence of closing degrees was derived from sim-ulation; control step of addition polymerization interaction in coating process was absorbing mass transfer process, so the more closed to surface of particle the multiple hydroxyl com-pounds were, the easier interactions with isocyanate were. Simulation results represented the compatibility relationship between surfactant and multiple hydroxyl compounds. The isolating and coating processes of α-olefin drag reducing polymer were further understood on molecule and atom level through above simulation research, and based on the simulation, a referenced theoretical basis was provided for practical optimal selection and experimental preparation of α-olefin drag reducing polymer particles suspension isolation agent.     

Studies of the association of chitosan and alkylated chitosan with oppositely charged sodium dodecyl sulfate

Cationic biopolymer chitosan has many applications in food, cosmetic and pharmaceutical industries. Grafting alkylated chains on its backbone can hydrophobically modify this water-soluble polymer.This paper concerns unmodified chitosan, alkylated chitosan and their interactions with a model anionic surfactant, sodium dodecyl sulfate (SDS). The solvent is pH 4 acetic acid solution. The purpose of this study is to highlight the hydrophobicity brought by the alkylated chains by comparing surface tension measurements and rheological properties of hydrophobically modified polymer (HMP) and chitosan solutions at 25 °C.Interactions of chitosan and HMP with surfactant have also been investigated giving information about surface activity and electrical conductivity of such systems. It results that alkylated chitosan/SDS system is more surface active than chitosan/SDS and it offers new potential applications in pharmaceutical and cosmetic fields because of the formation of amphiphilic complexes.     

Polymer colloid complexes of chitosan with sodium dodecyl sulfate in water-alcohol media

The formation of polymer colloid complexes based on chitosan and sodium dodecyl sulfate in aqueous ethanol media was studied. The infl uence of the composition of water-ethanol mixtures on the parameters of surfactant binding with chitosan, on the stability of the complexes, on the phase state of the system, and on the colloid-chemical properties of the complexes was analyzed. Addition of small (up to 34 vol %) amounts of ethanol to water enhances the intensity of binding of sodium dodecyl sulfate with the polyelectrolyte and promotes formation of insoluble associates.     

Effect of surfactant adsorbed on encapsulation of fine inorganic powder with soapless emulsion polymerization

The encapsulation of fine inorganic powder was carried out with the soapless emulsion polymerization of methyl methacrylate in water in the presence of the powder, a layer of surfactant being adsorbed. The powder used was titanium dioxide. Surfactants added prior to the polymerization were sodium dodecyl sulfate, dodecyltrimethyl ammonium bromide, and polyoxyethylene sorbitan mono-oleate. The encapsulation state of the powder with polymer was closely related to the amount of surfactant adsorbed on the powder; and an amount of adsorption above a certain value was necessary for uniform encapsulation. Ionic surfactants were more useful than nonionic in the surfactants used, and could be adsorbed utilizing the electrostatic interaction between powder and the ionic end group. The combination of electric charges between the ionic end groups of surfactant and initiator was found to influence the molecular weight of capsulating polymer.     

Polymer–TiO2 composite nanorattles via RAFT‐mediated emulsion polymerization

In this work, successful synthesis of polymer nanorattles containing titanium dioxide pigment particles in the centers of air voids is reported. The method used amphiphilic macro‐RAFT copolymers as stabilizers for pigment dispersion and the subsequent encapsulation of the pigment with polymer. The particles were first encapsulated by a water swellable hydrophilic layer, followed by a hard hydrophobic layer. Nanorattles were formed by swelling of hydrophilic polymer layers on the surface of the encapsulated pigment particles in a basic solution at elevated temperature. After swelling, the outer hard polymer shell was crosslinked to improve its strength. Air void sizes of the nanorattles were found to be controlled by swelling time, temperature, and the hydrophilic polymer layer thickness. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Polymer encapsulation of yttrium oxysulfide phosphorescent particles via miniemulsion polymerization

Yttrium oxysulfide upconverting phosphor particles can absorb infrared light and emit dopant‐dependent visible phosphorescence. This unique optical property has been used for particle‐based immunoassay applications. In this study, upconverting phosphor particles were encapsulated with a functionalized polymer (carboxylated polystyrene) shell layer via several approaches, which included the following: (1) the physical adsorption of the carboxylated polystyrene polymer onto the phosphor surfaces, (2) the miniemulsification of the preformed carboxylated polystyrene in a solvent in the presence of the phosphor particles and the subsequent stripping off of the solvent, and (3) the miniemulsification and miniemulsion copolymerization of styrene and methacrylic acid in the presence of the phosphor particles with hexadecane as a costabilizer in combination with a surfactant (sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, or sodium dihexyl sulfosuccinate). Miniemulsion technology proved to be the most effective method for forming a functionalized polymeric nanoshell surrounding the phosphor particles. The morphology of the encapsulated phosphor particles was found to vary from symmetric core–shell (i.e., a uniform nanoshell layer with varying shell thicknesses), asymmetric core–shell, dumbbell‐like, or raspberry‐like partial encapsulation to multiparticle encapsulation. The amount of multiparticle encapsulation could be reduced by the postaddition of a surfactant, but it could not be eliminated completely. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1038–1054, 2007     

Reactive surfactants in heterophase polymerization: Colloidal properties,film‐water absorption,and surfactant exudation

In this article the results obtained with latexes prepared by emulsion polymerization with a conventional surfactant and a polymerizable surfactant (surfmer) are presented. For this study, well‐defined styrene‐butylacrylate latexes with a conventional nonreactive surfactant (sodium dodecyl sulfate) and a maleate diester surfmer, of which films can be easily cast, were used. The latex with the surfmer was prepared following a surfmer addition strategy to maximize the amount of surfmer bound to the particle surface, and not buried in the particle interior. The latex properties in terms of mechanical stability, film‐water absorption, and film‐surfactant exudation were assessed and compared. The mechanical stability and water‐absorption properties of the latex prepared with surfmer were better than those of the latex with sodium dodecyl sulfate. Additionally, by using a surfmer the surfactant migration to the film‐substrate and film‐air interfaces can be inhibited. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2994–3000, 2002     

Adsorption of Sodium Dodecyl Sulfate to Colloidal Titanium Dioxide: An Electrophoretic Fingerprinting Investigation

The adsorption of sodium dodecyl sulfate to colloidal titanium dioxide was investigated using the electrophoretic fingerprinting approach. An electrophoretic fingerprint is a contour diagram of the observed electrophoretic mobility as a function of the bulk solution pH and plambda, the log of the bulk solution conductivity. Surfactant adsorption was observed to be strong under acidic conditions, as illustrated in the dramatic changes in the electrophoretic fingerprints. Electrokinetic data were compared with adsorption isotherm data obtained by a depletion method and good qualitative agreement was found. The observed pH changes associated with surfactant adsorption suggested ligand exchange as a possible mechanism of adsorption. Electrophoretic fingerprinting was shown to be a powerful means of examining surfactant adsorption to colloidal particles. Copyright 2000 Academic Press.     

Aqueous dispersion behavior of drug particles by addition of surfactant and polymer

The effect of surfactant and polymer on dispersion stability of aqueous suspensions of 5-(3-ethoxy-4-pentyloxyphenyl)-2,4-thiazolidinedione (CT112) was investigated by measuring the adsorbed amount of surfactant and polymer, zeta potential, particle size, and sedimentation rate of CT112. The addition of celluloses rather than sodium dodecyl sulfate (SDS) provided a high stable suspension of CT112. In addition, mixed systems of celluloses and SDS enhanced CT112 dispersion more effectively. The mechanism of dispersion stability of CT112 by addition of SDS and celluloses is discussed.     

Physicochemical Properties of Aqueous Solutions of Binary Mixtures of Lignin Derivatives and Sodium Dodecyl Sulfate

Physicochemical properties of aqueous solutions of binary mixtures of lignosulfonates and sodium dodecyl sulfate were studied. Introduction of sodium dodecyl sulfate into solutions of high-molecular-mass lignosulfonates at certain ratios causes macrophase separation of the systems with the formation of loose precipitates. A synergistic effect of a decrease in the surface tension is observed in the mixed solutions. This effect increases with increasing lignosulfonate molecular mass and temperature. The revealed relationships are caused by hydrophobic interactions of hydrocarbon radicals of sodium dodecyl sulfate with hydrophobic segments of lignosulfonate polymer chains with the formation of micellar associates. Aqueous solutions of binary mixtures of lignosulfonates (с_LS ≥ 0.2 g dm^–3) and sodium dodecyl sulfate (с_DSNa ≥ 0.08 g dm^–3) can be recommended for use as surfactant formulations for high-temperature autoclave leaching of polymetal ores.     

Novel synthesis of nano‐calcium carbonate (CaCO3)/polystyrene (PS) core–shell nanoparticles by atomized microemulsion technique and its effect on properties of polypropylene (PP) composites

Calcium carbonate (CaCO₃)/polystyrene (PS) nanoparticles (<100 nm) with core–shell structure were synthesized by atomized microemulsion technique. The polymer chains were anchored onto the surface of nano‐CaCO₃ through triethoxyvinyl silane (TEVS) as a coupling agent. Ammonium persulfate (APS), sodium dodecyl sulfate (SDS) and n‐pentanol were used as initiator, surfactant, and cosurfactant, respectively. Polymerization mechanism of core–shell latex particles was discussed. Encapsulation of nano‐CaCO₃ by PS was confirmed by using transmission electron microscope (TEM). Grafting percentage of core–shell particles was investigated by Thermogravimetric Analyzer (TGA). Nano‐CaCO₃/PS core–shell particles were characterized by Fourier transform infrared (FTIR) spectrophotometer and differential scanning calorimeter (DSC). The results of FTIR revealed existence of a strong interaction at the interface of nano‐CaCO₃ particle and PS, which implies that the polymer chains were successfully grafted onto the surface of nano‐CaCO₃ particle through the link of the coupling agent. In addition, TGA and DSC results indicated an enhancement of thermal stability of core–shell materials compared with the pure nano‐PS. Nano‐CaCO₃/PS particles were blended with polypropylene (PP) matrix on Brabender Plastograph by melt process with different wt% of loading (i.e. 0.1–1 wt%). The interfacial adhesion between nano‐CaCO₃ particles and PP matrix was significantly improved when the nano‐CaCO3 particles were grafted with PS, which led to increased thermal, rheological, and mechanical properties of (nano‐CaCO₃/PS)/PP composites. Scanning electron microscope (SEM) and atomic force microscope (AFM) images showed a perfect dispersion of the nano‐CaCO₃ particles in PP matrix. Copyright © 2011 John Wiley & Sons, Ltd.     

The effect of sodium dodecyl sulfate and anion‐exchange silica gel on matrix‐assisted laser desorption/ionization mass spectrometric analysis of proteins

Sodium dodecyl sulfate (SDS), an anionic surfactant, is widely used in peptide and protein sample preparation. When the sample is analyzed by matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS), this surfactant can often cause signal suppression. We have previously reported an on‐probe sample preparation method using a suspension of anion‐exchange silica gel and sinapinic acid (i.e., gel‐SA suspension) as a matrix, thereby greatly improving the MALDI signal detection of the protein solutions containing SDS. In this study, we found that a certain amount of SDS enhanced the MALDI signal intensity for protein samples. This effect was also observed when using sodium decyl sulfate and sodium tetradecyl sulfate instead of SDS. Furthermore, this on‐probe sample preparation method using both SDS and the gel‐SA suspension improved the detection limit of protein samples in the MALDI‐MS analysis by about ten‐fold as compared to that of protein samples without SDS and the gel‐SA suspension. This method can be applied not only to the MALDI‐MS analysis of samples containing SDS, but also to the examination of proteins at femtomole levels or insoluble proteins such as membrane proteins. Copyright © 2009 John Wiley & Sons, Ltd.     

The pH dependence of dispersion of TiO2 particles in aqueous surfactant solutions

The pH dependence of dispersion of titanium dioxide (TiO₂) particles has been examined in the presence of surfactant molecules in water. Whereas particles were dispersed in water at acid and alkaline regions rather than at neutral region, the dispersion was enhanced at neutral region in an aqueous sodium dodecyl sulfate (SDS) solution and at acid and alkaline regions in an aqueous dodecyldimethylamine oxide (C₁₂DAO) solution. Considering the pH dependence of zeta potential, the adsorption models of surfactant molecules on a particle were estimated on the basis of the modes of hemimicelle and double-layer compression. While the particles that adsorbed Al³⁺ were remarkably dispersed around pH 6, their dispersion does not largely depend on pH in the addition of SDS, indicating the adsorption of SDS molecules to form double-layer compression in the whole pH region. Dynamic light-scattering measurement and electron microscopic observation suggested that the particles were dispersed in water as small flocs.     

Study of polymer-surfactant interactions via surface tension measurements

Interactions between a polymer and a surfactant were studied via surface tension measurements. Poly(ethylene glycol) and sodium dodecyl sulfate were used as a polymer and a surfactant, respectively. The addition of polymer affected the CMC value of the surfactant. The interpretations of the data and theoretical plots of polymer-surfactant interactions are discussed using a theoretical model. Received: 28 September 2000 Accepted: 3 October 2000     

Interactions between chitosan and SDS at a low-charged silica substrate compared to interactions in the bulk--the effect of ionic strength

The effect of ionic strength on association between the cationic polysaccharide chitosan and the anionic surfactant sodium dodecyl sulfate, SDS, has been studied in bulk solution and at the solid/liquid interface. Bulk association was probed by turbidity, electrophoretic mobility, and surface tension measurements. The critical aggregation concentration, cac, and the saturation binding of surfactants were estimated from surface tension data. The number of associated SDS molecules per chitosan segment exceeded one at both salt concentrations. As a result, a net charge reversal of the polymer-surfactant complexes was observed, between 1.0 and 1.5 mM SDS, independent of ionic strength. Phase separation occurs in the SDS concentration region where low charge density complexes form, whereas at high surfactant concentrations (up to several multiples of cmc SDS) soluble aggregates are formed. Ellipsometry and QCM-D were employed to follow adsorption of chitosan onto low-charged silica substrates, and the interactions between SDS and preadsorbed chitosan layers. A thin (0.5 nm) and rigid chitosan layer was formed when adsorbed from a 0.1 mM NaNO3 solution, whereas thicker (2 nm) chitosan layers with higher dissipation/unit mass were formed from solutions at and above 30 mM NaNO3. The fraction of solvent in the chitosan layers was high independent of the layer thickness and rigidity and ionic strength. In 30 mM NaNO3 solution, addition of SDS induced a collapse at low concentrations, while at higher SDS concentrations the viscoelastic character of the layer was recovered. Maximum adsorbed mass (chitosan + SDS) was reached at 0.8 times the cmc of SDS, after which surfactant-induced polymer desorption occurred. In 0.1 mM NaNO3, the initial collapse was negligible and further addition of surfactant lead to the formation of a nonrigid, viscoelastic polymer layer until desorption began above a surfactant concentration of 0.4 times the cmc of SDS.     

A Facile One‐Step Method to Prepare Three‐Dimensional Ordered Latex Particles

Three‐dimensional ordered latex particles were prepared in presence of polymerizable anionic emulsifier—sodium undec‐10‐enoate (UDNa) in emulsion polymerization. Only under a certain monomer/emulsifier ratio can we get such a result. Three‐dimensional ordered latex particles cannot be acquired with the use of conventional emulsifiers such as sodium dodecyl sulfate (SDS), etc. The double bond of polymerizable emulsifier can copolymerize with the main monomer and become covalently bound to integrate with the main polymer chains which result in stable latexes. TEM and SEM images show that whether it is diluted or not the latexes can always keep in the three‐dimensional regularly order.     

Effect of anionic surfactant on alginate‐chitosan polyelectrolyte multilayer thickness

Alginate and chitosan are among the most common biopolyelectrolytes. Surfactants can be included in alginate and chitosan formulations in order to improve their physical and functional properties. In the present study, the effect of the anionic surfactant sodium dodecyl sulfate (SDS) on alginate‐chitosan polyelectrolyte multilayer (PEM) films is reported for the first time. Layer‐by‐layer deposition technique was employed to prepare the PEM samples and the samples were characterized by ellipsometry, X‐ray reflectivity, atomic force microscopy, and quartz crystal microbalance with dissipation. Incorporation of SDS into PEM formulations increased the film thickness and an increased adsorption behavior between alginate and chitosan layers are observed. Since the concentration of SDS was below its critical micelle concentration, no micelle formation was expected and hydrophobic‐hydrophobic interaction between alginate and SDS might be the main reason. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 1798–1803     

A polyacrylate prepared using polyurethane surfactants: properties of emulsion and film

The designed polyurethane surfactant (PUS) was used as a macromolecular surfactant for the preparation of polyacrylate emulsion without any other surfactants and stabilizers. The resultant polymer emulsion and film properties were compared with those of the emulsion prepared with sodium dodecyl sulfate (SDS). Long shelf-life of the polymer emulsion can be achieved at proper composition. Polymer particles show core-shell and nano-scale structure with narrow distribution. Thermoanalysis results show phase separation in the polymer film, which leads to gloss decrease with the PUS content increase. Such polymer films show good water resistance and mechanical strength.     

Surfactant assisted polymerization of tetrafluoroethylene in supercritical carbon dioxide with a pilot scale batch reactor

Chain‐free radical polymerization of tetrafluoroethylene (TFE) was carried out in supercritical carbon dioxide (scCO₂), at 50 °C and 121–133 bar, with tertiary‐amyl‐per‐pivalate as a free radical initiator, using a 5‐L pilot scale batch reactor. Experiments were carried out both in the absence and in the presence of perfluoropolyether (PFPE) carboxylate surfactants. Stabilizers were employed under the free acid form and as sodium and calcium salts. An expanded fibrillated poly(TFE) was obtained in all experiments. In the case of surfactant‐free polymerizations, the product was mainly constituted by irregular shape macroparticles having size in the range 200–500 μm. Quite interestingly, when the free acid surfactant was used, a clear acceleration of the polymerization rate was observed and smaller polymer particles with more regular quasi‐spherical morphology were obtained. Melt fusion crystallinity of as‐polymerized poly(TFE) seemed not substantially affected by the presence of the stabilizers and was rather high (80–86%) suggesting that polymerization mainly occurs at polymer particle surface. All these elements suggest that FLUOROLINK® 7004H PFPE carboxylic acid decreases coagulation of primary polymer particles leading to an increase in polymer surface area. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 257–266, 2008     

Kinetics of sodium dodecyl benzene sulfonate adsorption on hematite and its interaction with polyacrylamide

This article describes the adsorption of sodium dodecyl benzene sulfonate, an anionic surfactant, on a hematite surface and that when the surface is preadsorbed with polyacrylamide. The adsorption of surfactant on a hematite surface has been studied through equilibration and during kinetics measurements at three pH levels, viz. 4.0, 7.0, 8.9. The surfactant adsorbs strongly on the hematite surface. The adsorption density at equilibrium as well as the rate of adsorption are dependent on the suspension pH. The maximum adsorption density has been observed at pH 4, which reflects strong adsorption of negatively charged sulfonate ions on the oppositely charged Fe₂O₃ surface (point of zero charge, 6.4). The adsorption density reaches its equilibrium value sooner in the case of an alkaline suspension and later in the case of acidic pH. The polymer surfactant interaction has been noticed in the present study and is also a function of pH. The hematite mineral when preadsorbed with the polymer draws fewer of the surfactant molecules at lower surface coverage (during the initial period of the kinetics measurement) irrespective of the pH. When the adsorption of the surfactant reaches a value which is near the equilibrium one, the pH effect is evident. In the case of acidic pH, the surfactant adsorbs more on the hematite surface when preadsorbed with the polymer compared to the bare surface. In the case of neutral or alkaline pH, however, the density of surfactant adsorption remains lower throughout the kinetics measurement when the surface is preadsorbed with the flocculant compared to the bare surface. The particles also remain flocculated till the end of the experiment, whereas at pH 4 the particles are deflocculated. In addition to pH, the electrostatic nature of the adsorbent and the presence of anionic surfactant have an influence on the flocculation–deflocculation phenomena. The polymer–surfactant interaction has been schematically represented. The surfactant is bound with polymeric chains as a combination of its monomeric form as well as in the form of association in the case of acidic media and in competition with polymer in the case of alkaline media. Received: 18 April 2000/Accepted: 2 August 2000