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1.
This study addresses the effect of particle structure and composition on the mobility and orientation of sodium dioctyl sulfosuccinate (SDOSS) surfactant molecules in polybutyl acrylate/polystyrene core/shell-type latex films near the film-air (F-A) and film-substrate (F-S) interfaces. In an effort to determine how the surface tension of the substrate influences the migration and orientation of the SDOSS surfactant molecules, polytetrafluoroethylene (PTFE) and liquid Hg substrates were used. It appears that, as the concentration of styrene monomer in the latex increases, SDOSS migrates toward the F-A and F-S interfaces. As the surface tension of the substrate changes from 18 mN/m in PTFE to 400 mN/m for liquid Hg, the surfactant also migrates toward the two interfaces. For the latex particles composed of 50%/50% styrene/n-butyl acrylate (Sty/n-BA) latex copolymer, the hydrophilic SO−3Na+ groups of SDOSS surfactant are present primarily near the F-A interface, and they appear to be mostly parallel to the surface for the films cast on the PTFE surface. For the latex films cast on the liquid Hg surface, the SDOSS hydrophilic surfactant groups are found to be preferentially parallel near the F-A interface and perpendicular near the F-S interface. These studies indicate that the surfactant concentration and its orientation throughout the latex film change as a function of the initial monomer composition and the surface tension of the substrate. Furthermore, the SDOSS concentration appears to vary with depth into the latex interfaces. © 1996 John Wiley & Sons, Inc. 相似文献
2.
These studies examine how various latex copolymer compositions, ranging from 100% n-BA to 50%/50% Sty/n-BA, may influence sodium dioctylsulfosuccinate (SDOSS) mobility, diffusion, and orientation near the film–air (F–A) and film–substrate (F–S) interfaces. Polarized attenuated total reflection Fourier transform infrared spectroscopy is utilized to examine the surfactant behavior in Sty/n–BA latexes at the F–A and F–S interfaces. Based on the analysis developed for the purpose of these studies, the highest concentration of SDOSS is detected near the F–A interface for 50%/50% Sty/n-BA compositions. However, when the content of styrene in Sty/n-BA compositions. However, when the content of styrene in Sty/n-BA copolymer is diminished, the highest content of SDOSS is detected near the F–S interface. This behavior is particularly evident for 100% poly(n-BA) latexes. When SDOSS molecules are near the F–A and F–S interfaces, the SO3−Na+ hydrophilic ends are preferentially parallel to the surface, whereas hydrophobic tails are perpendicular. © 1996 John Wiley & Sons, Inc. 相似文献
3.
The interactions between sodium dodecylbenzene sulfonate (SDBS) and the components of an ethyl acrylate/methacrylic acid (EA/MAA) copolymer latex were examined and the influences of using D2O as the synthetic suspension medium were investigated. Whereas it is found that D2O has no detectable influence on the fully coalesced latex films, the film coalescence conditions are shown to significantly affect the nature of surfactant interactions within the film matrix. When films are prepared and stored under controllable low atmospheric water-vapor concentrations, hydrogen-bonding interactions between the surfactant SO3?Na+ groups and the copolymer acid functionality dominate. However, coalescence and storage of the films under higher relative humidity conditions results in a displacement of these interactions in favor of the hydrated form of the surfactant. It is also shown that the presence of an aromatic ring adjacent to the surfactant sulfonate group exerts an influence on the nature of the SO3? ··· HOOC interactions within the copolymer matrix. Relative to sodium dioctyl sulfosuccinate (SDOSS), the aromatic group near hydrophilic end of SDBS increases the strength of the S? O bond in the presence of acid interactions. © 1993 John Wiley & Sons, Inc. 相似文献
4.
Molecular level interactions between surfactants and copolymers as well as transient effects during latex film formation play an important role in latex technology. Photoacoustic (PA) and attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy were utilized for the characterization of interactions between sodium dioctylsulfosuccinate and ethyl acrylate/methacrylic acid (SDOSS/EA/MAA) copolymer in latex films at both the film–air and film–substrate interfaces. It is shown that the splitting of the asymmetric S? O stretching normal vibrations of the SO groups in the presence of Na+ counterions occurs only when weak ? COOH acid groups of latex are present. The absence of the COOH groups either by neutralization of latex or intentional synthesis eliminates the S? O···H? O? associations that are the primary source of the symmetry changes resulting in the splitting of the S? O symmetric mode at 1050 cm?1 to two bands at 1046 and 1056 cm?1. 相似文献
5.
This study focuses on the behavior of sodium dioctylsulfosuccinate (SDOSS) in 50/50 w/w % polystyrene/poly(butyl acrylate) (p-Sty/p-BA) latex films. Specifically, mobility and orientation are examined in the context of the film formation by the use of dynamic mechanical thermal analysis and attenuated total reflectance (ATR) Fourier transform infrared (FT-IR) spectroscopy. While for the homopolymer blends of p-Sty and p-BA, two Tg values resulting from a phase separation of p-Sty and p-BA phases are observed, only a single Tg is detected for a copolymer of the same mixture, indicating a single phase within the film. ATR FTIR spectroscopic data indicate that the phase separation of p-Sty and p-BA blends does not occur uniformly across the film. After coalescence, p-Sty particles produce a significant degree of stratification at approximately 1.6 μm from the film surface. At this depth, the polystyrene rings assume preferentially parallel orientation to the film surface. At the same time, the hydrophilic groups of SDOSS surfactant (SO−3Na+) are oriented preferentiallyparallel to the surface. Under high relative humidity conditions, water is able to diffuse into the film and swells the surface layers, thus causing them to expand. As a result, the top, predominately poly-n-BA surface becomes “thicker», and p-Sty phase appears to be near 2.3 μm from the surface. The polystyrene rings maintain their preferential parallel orientation to the surface, but the hydrophilic groups of SDOSS are able to diffuse into the film with the water uptake and are thus not present at the filmair interface. © 1996 John Wiley & Sons, Inc. 相似文献
6.
Polarized attenuated total reflection Fourier transform infrared (ATR FT–IR) spectroscopy was used to identify the mobility and surfactant exudation of sodium dioctyl sulfocuccinate (SDOSS) surfactant molecules to the film–air (F–A) and film–substrate (F–S) interfaces in styrene/n-butyl acrylate (Sty/n-BA) latex films. It was found that, depending upon the latex particle composition, the surfactant molecules could be driven to the F–A or F–S interfaces. The primary factors that governed the direction of exudation were the compatibility of the latex components, interfacial film-substrate surface tension, and the chemical composition of the latex particles. Concentration, as well as orientation, of the hydrophilic SONa+ surfactant ends changed as a function of depth and the latex particle composition. © 1993 John Wiley & Sons, Inc. 相似文献
7.
The intermolecular interactions between methanol/water and Nafion™ membranes have been investigated using IR spectroscopy. The evolution of IR spectra of the Nafion™ membranes, immersed in various concentrations of methanol solution depends strongly on the methanol concentration. The O–H bending vibration modes at 1,636, 1,660 and 1,672 cm–1 associated with the hydrogen bonding of (H3O+…SO3–) as well as (CH3OH2+…SO3–), and at 1,702, 1,717 and 1,711–1,736 cm–1 associated with the hydrogen bonding of (CF2…H–O–CH3), (CF2…H–OH), (CF2…+H3O) and (CF2…H–OSO2–) were observed. The vibration mode of (CF2…H–O) was found to be appearing obviously at 3,821–3,900 cm–1 when the Nafion™ membrane was immersed in the methanol solution with concentration higher than 6 M. On the other hand, the wavenumber of the O–H stretching peak increases with an increase in the methanol concentration. Results of IR spectra revealed that the methanol molecules show better capability to penetrate into the hydrophobic domain of the Nafion™ membrane than water. The intermolecular interaction between the hydrophobic domains of Nafion™ and methanol molecules becomes more observable at a higher methanol concentration. 相似文献
8.
One of the reactions leading to the formation of polyurethane (PU) crosslinked networks is the reaction of NCO and OH functionalities.
In this study, we examined how crosslinking reactions of hexamethylene diisocyanate isocyanurate and polyacrylate near the
film-air (F-A) and film-substrate (F-S) interfaces in urethane coatings may affect crosslink density as well as other network
properties. While at the initial stages of the crosslinking reactions, solvent evaporation competes with the urethane network
formation and isocyanate consumption changes at various depths from the F-A and F-S interfaces. Quantitative analysis of the
NCO consumption as a function of depth showed that the NCO concentrations change from 2.35×10−5 to 2.09×10−5 M, while going from 0.27 to 1.14 μm. During reaction times not exceeding two to three hours, the NCO consumption at the F-A
and F-S interfaces is consumed more rapidly. At low relative humidity conditions, excessive amounts of unreacted NCO exists
at both the F-A and F-S interfaces. However, at the extended reaction times, NCO concentration levels at the F-S are greater
than at the F-A interface, and the NCO concentration differences can be as high as 3×10−5 M. In this study we also examined how crosslinking reactions of hexamethylene diisocyanate (HDI) isocyanurate and polyacrylate
near the F-S interfaces in urethane films may affect orientation and distribution of urethane functionalities.
Department of Polymers and Coatings, Fargo, ND 58105. 相似文献
9.
《Carbon》1987,25(4):495-502
IR spectroscopic studies were carried out on the character of interactions between adsorbed molecules of SO2 and O2, H2O or H2S on the surface of carbons. The character of bonding between adsorbed molecules and the carbon films depends on the chemical structure of the surface functional groups. Weakly adsorbed SO2 gives rise to the bands at 1330 and 1140 cm−1. Strongly held SO2 is indicated by the band around 1045 cm−1. Catalytic activity of carbon films in the oxidation of aqueous sulfur dioxide solution has been studied. The results suggest that Superoxide ions take part in the adsortion of acids on the surface of carbon as well as in the catalytic oxidation of aqueous SO2 solution by O2. 相似文献
10.
Saad Ahmed Muhammad Ali Yangben Cai Yunhua Lu Zaheer Ahmad Santosh Khannal Shiai Xu 《应用聚合物科学杂志》2019,136(22):47603
In the present study, multi-walled carbon nanotubes (MWCNTs) were sulfonated by 1,3-propane sultone and distillation–precipitation polymerization, respectively, and then incorporated into chitosan (CS) to prepare CS/MWCNTs composite membranes for fuel cell applications. CS/MWCNTs membranes show better thermal and mechanical stability than pure CS membrane due to the strong electrostatic interaction between the SO3H groups of MWCNTs and the NH2 groups of CS, which can restrict the mobility of CS chain. The sulfonated MWCNTs provide efficient proton hopping sites ( SO3H, SO3− …. 3+HN ), thereby resulting in the formation of continuous proton conducting channels. The composite membranes with 5 wt % of MWCNTs modified by two different ways show a proton conductivity of 0.026 and 0.025 S·cm−1, respectively. In conclusion, CS/MWCNTs membrane is a promising proton exchange membrane for fuel-cell applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47603. 相似文献
11.
Quyen H. Le Courtney Calahoo Yang Xia Johannes Buchheim Caio B. Bragatto Lothar Wondraczek 《Journal of the American Ceramic Society》2020,103(9):4939-4956
We report on the individual roles of charge carrier density and network modification in sodium ion conducting glasses from the Na2O-P2O5-SO3-AlF3 (NAPFS) system. For this, a broad range of glass compositions was considered across the series of 44Na2O/(56 – x − y)P2O5/xAlF3/ySO3, 47Na2O/(53 − x − y)P2O5/xAlF3/ySO3, and 50Na2O/(50 − x − y)P2O5/xAlF3/ySO3, with x = 8, 12, 16, 20 and y = 0, 5, 7, 10, 12. Impedance spectroscopy was conducted on these glasses at frequencies from 10−2 to 106 Hz and over temperatures from 50 to 250°C, and complemented by structural analyses using Raman spectroscopy and nuclear magnetic resonance data. While the trends in dc conductivity and activation energy follow that of Na2O content (increasing from 44 to 50 mol%), substantial enhancement of conductivity (by about two orders of magnitude) and correspondingly lower activation energy were also found for constant Na2O concentration when adjusting SO3 or AlF3 within specific limits of glass structure. 相似文献
12.
《Microporous and mesoporous materials》2004,67(1):95-106
A micelle-templated material with Si/Al=2.5 has been synthesised, then either calcined to provide the H form of the sample or partially exchanged with Li+ and Na+ ions. After surfactant removal, all samples were microporous, with average diameter around 18 Å.In the H form, sizeable formation of octahedral and pentacoordinated Al was found, whereas, with Na sample, 27Al NMR spectra showed minimal occurrence of octahedral Al, so indicating that Na+ cations, in contrast with protons, do compensate tetrahedral Al in the silicate structure.All samples have been characterised via FT-IR spectroscopy of surface hydroxyl species and adsorbed probe molecules acting as Lewis bases (carbon monoxide, ammonia, propene).Although the Si/Al ratio is close to that of Y zeolites, these systems showed definitely weaker acidity, similar to that of amorphous silica–aluminas of low Al content. With H sample, no zeolite-like Brønsted site has been observed, the more acidic hydroxyls being those absorbing at 3660 cm−1, ascribed to SiOAl(OH)OSi groups, able to transfer a proton to ammonia, but not to propene, and undergoing with CO a shift of about 220 cm−1.With Na sample, the nearly complete exchange caused the disappearance of more acidic hydroxyls and of Al3+ Lewis sites; a fraction of Na+ cations resulted not accessible to probe molecules, being probably buried into the thick walls. With Li sample, some AlOH species and Al3+ Lewis sites are at the surface, as a consequence of the lower degree of exchange. 相似文献
13.
《Desalination》1987,61(3):263-274
The daily performance of a 49 ms3/d RO unit is reported in terms of the water and TDS transport parameters A and B, respectively. The rejections of the ions Na+, SO2-4, Cl− and NO−3, and alkalinity, boron and selenium are also reported for the begining and end of the testing period. The single stage RO unit consisted of six spiral-wound membrane elements (Model 4040-MSY- CAB3 manupactured by Hydranautics) placed in series. 相似文献
14.
In this article, a redox-responsive poly(ionic liquid) (redox-PIL) hydrogel Poly(1-vinyl-3-propionate imidazole phenothiazine sulfonic acid)-chitosan [Poly(VPI+PTZ-(CH2)3SO3−)-CS] was produced by using chitosan (CS) crosslinking with redox-PIL Poly(1-vinyl-3-propionate imidazole phenothiazine sulfonic acid [Poly(VPI+PTZ-(CH2)3SO3−)]. The incorporation of redox-active counter anions 3-(phenothiazine-10-yl) propane 1-sulfonic acid anions (PTZ-(CH2)3SO3−) into cationic PIL-polyimidazole rendered Poly(VPI+PTZ-(CH2)3SO3−) with electron catalytic ability, ionic conductivity, and electron conductivity. Poly(VPI+PTZ-(CH2)3SO3−)-CS combines the properties of hydrogel and redox-PIL, thus offering intrinsic porous conducting frameworks and promoting the transport of charges, ions, and molecules, leading hydrogel with excellent electrochemical properties. The crosslinking occurrence of Poly(VPI+PTZ-(CH2)3SO3−) and CS resulting from the synthetic process of hydrogel was verified by differential scanning calorimetry and thermogravimetric analysis. A three-dimensional polymer network hydrogel with good biocompatibility and permeability was formed after crosslinking. In addition, only 64% weight loss within 600 °C was observed in Poly(VPI+PTZ-(CH2)3SO3−)-CS representing its thermally stable performance. When used as an electrochemical sensor, the hydrogel-modified gold electrode improved the electrocatalytic oxidation of cysteine. Differential pulse voltammetry results indicated that the detection range was from 5 × 10−8 to 5 × 10−3 M and the limit of detection was 6.64 × 10−8 M. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48051. 相似文献
15.
Ramon E. Vera Franklin Salazar-Rodríguez Ronald Marquez Ana M. Forgiarini 《Journal of surfactants and detergents》2020,23(3):603-615
In this work, we present the effects of salts on sodium dodecyl benzene sulfonate micellization and on the interfacial performance of a sodium dodecyl benzene sulfonate–heptane–brine system at optimum formulation, i.e., hydrophilic–lipophilic deviation (HLD) = 0. In order to do that, interfacial tension and dilational interfacial rheology properties of surfactant–heptane–water systems at optimum formulation are measured using an interfacial spinning drop tensiometer with an oscillating velocity, which can accurately measure interfacial rheology properties at both low and ultralow interfacial tensions. The brines used contain one of the following salts: MgCl2, CaCl2, NaCl, NH4Cl, NaNO3, CH3COONa, or Na2SO4. We performed a one-dimensional salinity scan with each of these salts to achieve an optimum formulation. In relation to the Hofmeister series, we found that, at optimum formulation, systems with chaotropic ions (NH4+, NO3−) present interfaces with ultralow interfacial tensions, very low dilational modulus, and a low phase angle, whereas kosmotropic ions (Mg2+, Ca2+, SO4−2) generate high interfacial tension and high rigidity monolayers. Intermediate ions in the Hofmeister series (Na+, CH3COO−, Cl−) present interfaces with intermediate properties. Furthermore, according to the Hofmeister series, interfaces can be respectively ordered from higher to lower rigidity for surfactant counterions Mg2+ > Ca2+ > Na+ > NH4+ and coions SO42− > CH3COO– > Cl− > NO3−, which correspond to a salting-out (highest rigidity) and salting-in (lowest rigidity) effect. We observed that counterions have a more significant effect on surfactant–oil–water system properties than those that act as coions. 相似文献
16.
《Carbon》2015
Functionalized porous carbon with three-dimensional (3D) interconnected pore structure has been successfully synthesized through direct heat-treatment of KOH-soaked soybeans. Benefiting from heteroatoms (N, O) doping, interconnected porous carbon framework with high surface area as well as high packing density (up to 1.1 g cm−3), the as-obtained porous carbon material exhibits high volumetric capacitance of 468 F cm−3, good rate capability and excellent cycling stability (91% of capacitance retention after 10,000 cycles) in 6 M KOH electolyte. More importantly, the as-assembled symmetric supercapacitor delivers high volumetric energy density of 28.6 Wh L−1 in 1 M Na2SO4 aqueous solution. 相似文献
17.
FT-IR spectroscopy was used to collect spectra of γ-aminopropyltriethoxy silane (γ-APS) coupling agent deposited on KBr plates, modeling the silane interphase of composites, to study the effects of heating the γ-APS film under various environmental conditions. This coupling agent is used in fiber-reinforced epoxy composites. An aminebicarbonate salt forms when the sample is dried in a moist carbon dioxide environment giving rise to a series of bands from 2800 to 2000 centimeter−1 (cm−1) and bands at 1637 cm−1, 1330 cm−1, 696 cm−1, and 663 cm−1. The primary amine group is split into two bands at 1572 cm−1 and 1486 cm−1 in the NH3+ form. Heating removes the aminebicarbonate salt at temperatures above 95°C and condenses the γ-APS polymer to a polysilsesquioxane film. The aminebicarbonate salt partially reforms if the γ-APS film is stored in a moist CO2 environment. At temperatures above 120°C the primary amine of γ-APS is oxidized in air to imine groups. In the process of evolving the CO2 the polymer is further condensed and the amine groups can be converted to imines if the temperatures exceeds 120°C. Both processes reduce the reactivity of the coupling agent with the epoxy resin. The structure of the silane interphase must be controlled during the processing of the composite to yield materials with maximum properties. 相似文献
18.
《Ceramics International》2017,43(13):9960-9967
P2-type layered Na2/3Ni1/4Mn3/4O2 has been synthesized by a solid-state method and its electrochemical behavior has been investigated as a potential cathode material in aqueous hybrid sodium/lithium ion electrolyte by adopting activated carbon as the counter electrode. The results indicate that the Na+/Li+ ratio in aqueous electrolyte has a strong influence on the capacity and cyclic stability of the Na2/3Ni1/4Mn3/4O2 electrode. Increase on the Li+ content leads to a shift of the redox potential towards a high value, which is favorable for the improvement of the working voltage of the layered material as cathode. It is found that the coexistence of Na+ and Li+ in aqueous electrolyte can improve the cyclic stability for the Na2/3Ni1/4Mn3/4O2 electrode. A reversible capacity of 54 mAh g−1 was obtained with a high cyclability as the Na+/Li+ ratio was 2:2. Furthermore, an aqueous hybrid ion cell was assembled with the as-proposed Na2/3Ni1/4Mn3/4O2 as cathode and NaTi2(PO4)3/graphite synthesized in this work as anode in 1 M Na2SO4/Li2SO4 (mole ratio as 2:2) mixed electrolyte. The cell shows an average discharge voltage at 1.2 V, delivering an energy density of 36 Wh kg−1 at a power density of 16 W kg−1 based on the total mass of the active materials. 相似文献
19.
Satya P. Varma 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1976,26(1):391-394
The replacement of CaO by Na2O in C3A has been studied by infrared spectroscopy. At up to 2.06% Na2O, C3A bands are slightly displaced indicating the existence of a solid solution. From 3.9 to 4.8% Na2O, the spectrum is largely modified and a different pattern with vibrations at 730, 790 and 872 cm?1 is observed. At 4.8–6.0% Na2O there is little further change, but the band at 872 cm?1 is broadened. It is proposed that modifications with 3.9–6% Na2O can be represented more adequately by the formula NC14A5 (4.57% Na2O) rather than NC8A3 (7.59% Na2O). Above 6% Na2O, other compounds such as free CaO, N2C3A5 and NA are also formed. 相似文献
20.
《Ceramics International》2019,45(14):17120-17127
Development of metal nitride-based thin film binder-free electrodes is a rapidly emerging area of research for the development of supercapacitors. The manganese nitride (Mn3N2) binder-free thin film electrodes were prepared using DC magnetron sputtering process. X-ray diffraction and the Raman spectroscopy characterization confirmed the formation of the tetragonal phase of Mn3N2 thin film. Field emission scanning electron microscopy revealed that the Mn3N2 particles are in nanoscale range and the particles with pyramidal shape are distributed uniformly on the surface of the film. Further, the Mn3N2 electrodes were examined by cyclic voltammetry and galvanostatic charge-discharge measurements to investigate the supercapacitive properties. The electrochemical measurements were performed on Mn3N2 deposited on conducting stainless steel substrates in different electrolytes (KOH, KCl and, Na2SO4 at 1 M concentration). The effect of various electrolytes on the areal capacitance, cycling stability, capacitance retention of the Mn3N2 electrodes was investigated. The Mn3N2 electrodes show high areal capacitance of 118 mF cm−2 for KOH, 68 mF cm−2 for KCl and 27 mF cm−2 for Na2SO4 at a scan rate of 10 mV/s. Moreover, the Mn3N2 electrodes indicated excellent cycling stability with capacitance retention of 98.5%, 89% and 83% for KOH, KCl, and Na2SO4, electrolytes respectively after 4,000 cycles. A comparative study on the electrochemical supercapacitive properties of the Mn3N2 electrode in different aqueous electrolytes is reported for the next generation electrochemical energy storage devices. 相似文献