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1.
The surface tension of disodium hexadecyl diphenyl ether disulfonate (C16‐MADS) was measured at different NaCl concentrations (0.00–0.50 mol L?1) and temperatures (298.0–318.0 K) using the drop‐volume method. The results show that, with increasing temperature, the critical micelle concentration (CMC) of C16‐MADS increases slightly, but the maximum surface adsorption capacity (Γmax) at the air–water interface decreases. When the concentration of NaCl was increased from 0.00 to 0.50 mol L?1, the CMC of C16‐MADS decreased from 1.45 × 10?4 to 4.10 × 10?5 mol L?1, but the surface tension at the CMC (γcmc) was not affected. When the concentration of NaCl was increased at 298.0 and 303.0 K, the Γmax of C16‐MADS increased. When the temperature was increased from 308.0 to 318.0 K, the surface excess concentration (Γmax) of C16‐MADS abnormally decreased from 2.26 to 1.41 μmol m?2 with increasing NaCl concentration. The micellization free energy () decreased from ?63.98 to ?76.20 kJ mol?1 with increase of temperature and NaCl concentration. The micellar aggregation number (Nm) of disodium hexadecyl diphenyl ether disulfonate (C16‐MADS) was determined using the molecule fluorescence probe method with pyrene as probe and benzophenone as quencher. The results show that an appropriate Nm could be measured only at surfactant concentration above the CMC. The Nm increased with an increase in C16‐MADS concentration, but the micropolarity in the micelle nucleus decreased. The temperature had little effect on Nm. Compared with typical single hydrophilic headgroup surfactants, aggregates of C16‐MADS exhibit different properties.  相似文献   

2.
The linear alkylated diphenylmethane sulfonate (C12‐DSDM) was synthesized by a four‐step reaction with lauric acid, diphenylmethane and chlorosulfonic acid as raw materials. The structure of the final product was characterized by MS. The air–liquid surface tensions at various temperatures and salt solutions (NaCl) were measured by using the drop‐volume technique and the thermodynamic parameters of the micellization were calculated. The results show that the critical micelle concentration (CMC) and γCMC of the surfactant are 1.452 mmol L?1 and 38.49 mN m?1 at 298 K. With an increase in temperature, the CMC gradually increases, the γCMC and the maximum surface adsorption capacity Γmax decrease. The free energy of micelle formation is negative (?51.2 to ?60.5 kJ mol?1).  相似文献   

3.
In the present work, a two-step method was adopted to synthesize a series of novel Gemini surfactants using N,N-dimethylalkyl amines (alkyl length = C12, C16 and C18), epichlorohydrin, and n-phenyllenediamine as starting materials. The products were characterized using mass spectroscopy (MS) and nuclear magnetic resonance spectroscopy (1H NMR). Systematic experiments were conducted to evaluate their surface activity, foaming properties, and antibacterial performance. Results showed the critical micelle concentrations (CMC) of the C12-based, C16-based, and C18-based phenylenediamine surfactants were 3.295 × 10−3, 2.532 × 10−4, and 3.140 × 10−4 mol L−1 at 298 K, respectively, with corresponding surface tension (γcmc) values of 28.24, 31.95, and 35.06 mN m−1 under the same conditions. The Gemini surfactants showed not only good surface activity and foaming properties, but also demonstrated good antimicrobial performance against Gram-positive and Gram-negative bacteria and fungi.  相似文献   

4.
Dialkylated diphenylether disulfonate with different alkyl chain lengths (Cn‐DADS, n = 8, 10 and 12) has been synthesized by Friedel‐Crafts alkylation of olefins (C8, C10 and C12) and diphenyl oxide, followed by sulfonation and neutralization with fuming sulfuric acid. Sulfated zirconia solid acids were prepared and used to catalyze the alkylation reaction. The structure of sulfated zirconia solid acids was identified by infrared spectroscopy. The title compounds were confirmed by infrared spectroscopy and electrospray ionization‐mass spectrometry. Equilibrium surface tension measurements show that the critical micelle concentration (CMC) decreases with an increase in chain length, and the surface tension at CMC (γcmc) of C8‐DADS is the lowest. The minimum area per molecule (Amin) values of Cn‐DADS increase, while the surface excess concentration (Γmax) values decrease with the increase of the alkyl chain length. C10‐DADS has the highest pC20 and CMC/C20 among Cn‐DADS.  相似文献   

5.
A type of switchable tertiary amine Gemini surfactant, N,N′‐di(N,N‐dimethyl propylamine)‐N,N′‐didodecyl ethylenediamine, was synthesized by two substitution reactions with 3‐chloro‐1‐(N,N‐dimethyl) propylamine, bromododecane and ethylene diamine as main raw materials. The structure of the product was characterized by FTIR and 1H‐NMR. We also investigated the surface tension when CO2 was bubbled in different concentrations of surfactant solution and the influence of different CO2 volumes on surface tension under a constant surfactant concentration. Finally the surface tension curve and the related parameters were acquired by surface tension measurements. The experimental results showed that the structure of the synthesized compounds were in conformity with the expected structure of the surfactant, and displayed a better surface activity after bubbling CO2. The critical micelle concentration (CMC) surface tension at CMC (γcmc) pC20 (negative logarithm of the surfactant's molar concentration C20, required to reduce the surface tension by 20 mN/m) surface excess (Γmax) at air/solution interface and the minimum area per surfactant molecule at the air/solution interface (Amin) were determined. Results indicate that the target product had good surface activity after bubbling CO2.  相似文献   

6.
A series of carboxylic ester‐containing imidazolium‐based zwitterionic surfactants, namely, monoalkyl 2‐(3‐methylimidazolium‐1‐yl) succinate inner salts (CnMimSU, n = 8, 10, 12 and 14), have been synthesized. Their structures were confirmed by 1H NMR, 13C NMR and FTIR. The typical physicochemical properties parameters such as isoelectric point, critical micelle concentration (CMC), surface tension at CMC (γCMC), surface pressure at CMC (ΠCMC), adsorption efficiency (pC20), the maximum surface excess (Γm), the minimum molecular cross‐sectional area (Amin) and the value of CMC/C20 were determined. The effect of the long‐chain length on the important physicochemical properties of CnMimSU was studied. It is found that the surface activity of CnMimSU is enhanced with the long‐chain length increases.  相似文献   

7.
Disodium monoalkyl diphenyl oxide disulfonates (MADS) with different carbon chains (Cn‐MADS, n = 8, 12, 16) were synthesized through the steps of alkylation‐sulfonation‐neutralization using fatty alcohols (C8, C12, C16), diphenyl oxide and fuming sulfuric acid (20 % free SO3) as reagents. The structures of the products were identified by infrared spectroscopy and electrospray ionization‐mass spectrometry. The surface properties, emulsification, wettability alteration and salinity and hardness tolerance of the products were systematically investigated. The results show that the critical micelle concentration (CMC) of C8MADS, C12MADS and C16MADS are 7.24 × 10?3, 1.49 × 10?3 and 2.09 × 10?4 mol/L. The surface tensions at the CMC (γCMC) of each product are 37.5, 38.9 and 46.8 mN/m. The negative logarithm of the surfactant concentration in the bulk phase required to produce a 20 mN/m reduction in the surface tension of the solvent (pC20) increases with the increase in the alkyl chain length. The emulsifying ability of C12‐MADS is better than C8‐MADS and C16‐MADS, and the MADS showed less oil‐wet nature. The salinity and hardness tolerance of MADS is much stronger than that of conventional surfactants.  相似文献   

8.
A novel bola‐type acrylic‐modified rosin ester tertiary ammonium salt surfactant (AETAS) with two hydrophilic groups and a rigid hydrophobic group was synthesized through a simple method from rosin acid, which is a natural raw material. The chemical structure of the synthesized surfactant was confirmed by infrared spectroscopy and nuclear magnetic resonance spectroscopy (1H NMR and 13C NMR). The critical micelle concentration (CMC) of the AETAS was 0.44 g/L, and the surface tension at the CMC (γcmc) was 45.02 mN/m. Self‐assembly behavior of the AETAS in aqueous solution was characterized by transmission electron microscopy. The micelle diameter of the AETAS was about 150 nm in aqueous solution. We also explored the synergy of the AETAS and soapnut saponin. The binary surfactant compound systems of the AETAS and soapnut saponin had obvious synergistic effect in enhancing surface activity when the mass ratio of AETAS/soapnut saponin was 1:1. The γcmc of soapnut saponin was 47.70 mN/m when the concentration reached 0.46 g/L, but the γcmc of mixtures decreased to 44.26 mN/m at 0.30 g/L. The emulsification ability of the mixtures was significantly improved and the emulsion performance increased from 245 to 595 s when the mass ratio of AETAS/soapnut saponin was 1:1.  相似文献   

9.
Surface and micellization behavior of some cationic monomeric surfactants, viz., cetyldiethylethanolammonium bromide (CDEEAB), cetyldimethylethanolammonium bromide (CDMEAB), tetradecyldiethylethanolammonium bromide (TDEEAB) and dimeric surfactants, i.e., alkanediyl‐α, ω‐bis(dimethylhexadecylammonium bromide) (C16‐s‐C16, 2Br? where s = 4, 12), butanediyl‐1,4‐bis(dimethyldodecylammonium bromide (C12‐4‐C12, 2Br?) and 2‐butanol‐1,4‐bis(dimethyldodecylammonium bromide) (C12‐4(OH)‐C12, 2Br?), was studied in water‐organic solvents [10 and 20 % v/v ethylene glycol (EG) and diethylene glycol (DEG)] by conductivity, surface tension and steady‐state fluorescence methods at 300 K. The main focus of the present work is on the study of the effect of organic solvents on the critical micelle concentration (CMC), Gibbs free energy of micellization (ΔG°m), Gibbs free energy of transfer (ΔG°trans), Gibbs adsorption energy (ΔG°ads) and some interfacial parameters such as the surface excess concentration (Γmax), minimum area per surfactant molecule (Amin) and surface pressure (πCMC). The aggregation number (Nagg) and Stern‐Volmer quenching constant (KSV) were also determined by the steady‐state fluorescence method. It was observed that Nagg decreased with increasing volume percent of organic solvent. The results exhibited an increase in CMC in water‐organic solvents as compared to the respective surfactants in pure water. The negative values of ΔG°m and ΔG°ads indicate a spontaneous micellization process. The thermodynamics of micellization revealed that the micellization‐reducing efficiency of glycols increases with the concentration and the number of ethereal oxygens in the glycol.  相似文献   

10.
In order to determine the structure‐performance relationship of nonionic‐zwitterionic hybrid surfactants, N,N‐dimethyl‐N‐dodecyl polyoxyethylene (n) amine oxides (C12EOnAO) with different polyoxyethylene lengths (EOn, n = 1–4) were synthesized. For homologous C12EOnAO, it was observed that the critical micelle concentration (CMC), the maximum surface excess (Γm), CMC/C20, and the critical micelle aggregation number (Nm,c) decreased on going from 1 to 4 in EOn. However, there were concomitant increases in surface tension at the CMC (γCMC), minimum molecular cross‐sectional area (Amin), adsorption efficiency (pC20), and the polarity ([I1/I3]m) based on the locus of solubilization for pyrene. The values of log CMC and Nm,c decreased linearly with EOn lengthening from 1 to 4, although the impact of each EO unit on the CMC of C12EOnAO (n = 1–4) was much smaller than that typically seen for methylene units in the hydrophobic main chains of traditional surfactants. Compared to the structurally related conventional surfactant N,N‐dimethyl‐N‐dodecyl amine oxide (C12AO), C12EOnAO (n = 1–4) have smaller CMC, Amin, and CMC/C20, but larger pC20, Γm, and Nm,c with a higher [I1/I3]m. This may be attributed to the moderately amphiphilic EOn (n = 1–4) between the hydrophobic C12 tail and the hydrophilic AO head group.  相似文献   

11.
Dodecyl diphenyl oxide disulfonate with different counterions (C12MADS‐M, M = Na, Mg, Ca) were synthesized using dodecyl alcohol, diphenyl oxide and SO3 as reagents through alkylation–sulfonation–neutralization. The structure of the product was characterized by infrared spectroscopy and electrospray ionization‐mass spectrometry. The surface and interfacial prosperities were investigated. The critical micelle concentration (CMC) of C12MADS‐Na, C12MADS‐Mg and C12MADS‐Ca was 1.23 × 10?3, 5.25 × 10?4 and 5.37 × 10?4 mol/L, respectively. The surface tension at CMC (γCMC) of C12MADS‐Na, C12MADS‐Mg and C12MADS‐Ca was 43.2, 37.1 and 36.6 mN/m, respectively. Interfacial tensions between crude oil and C12MADS‐M aqueous solution gave only a small change in the calcium chloride concentrations ranging from 50 to 10,000 mg/L.  相似文献   

12.
Three series of nonionic surfactants derived from polytriethanolamine containing 8, 10, and 12 units of triethanolamine were synthesized. Structural assignment of the different compounds was made on the basis of FTIR and 1H‐NMR spectroscopic data. The surface parameters of these surfactants included critical micelle concentration (CMC), surface tension at the CMC (γCMC), surfactant concentration required to reduce the surface tension of the solvent by 20 mN m?1 (pC20), maximum surface excess (Γmax), and the interfacial area occupied by the surfactant molecules (Amin) using surface tension measurements. The micellization and adsorption free energies were calculated at 25 °C.  相似文献   

13.
The complex formation between anionic polyelectrolyte poly(acrylic acid sodium salt) [NaPAA] and surface active ionic liquid (SAIL) lauryl isoquinolinium bromide [C12iQuin][Br] in aqueous media has been investigated by surface tension, isothermal titration calorimetry (ITC), and conductance. The self‐assembled structures have been characterized using dynamic light scattering (DLS) and turbidity measurements. A range of surface parameters have been calculated from tensiometric measurements including critical micelle concentration (CMC), surface excess concentration (Γcmc), surface pressure at the interface (Πcmc), minimum area occupied at air–solvent interface (Amin), adsorption efficiency (pC20), and surface tension at the CMC (γcmc). The thermodynamic parameters, i.e., standard enthalpy of micellization , standard free energy of micellization (), and standard entropy of micellization () have also been evaluated. Four different stages of transitions, corresponding to the progressive formation of NaPAA–[C12iQuin][Br] complex (C1), critical aggregation concentration (CAC), critical saturation concentration (C3) and CMC have been observed owing to strong electrostatic and hydrophobic interactions. The results obtained from DLS and turbidity measurements show that size of the aggregates first decreases and then increases in the presence of polyelectrolyte. The binding isotherms obtained using isothermal titration calorimetry (ITC) show the concentration dependence as well as the highly cooperative nature of interactions corresponding to formation of polyelectrolyte–SAIL complexes.  相似文献   

14.
Mixed micellization behavior of dodecyl sulfate-based ionic liquids, i.e., 1-propyl-3-methylimidazolium dodecyl sulfate [C3mim][DS] and 1-hexyl-3-methylimidazolium dodecyl sulfate [C6mim][DS] with sodium dodecyl sulfate (SDS), is investigated at (298.15, 308.15, and 318.15) K in aqueous medium. For this, the conductometric measurements are carried out to evaluate the critical micelle concentrations (cmc ), ideal critical micelle concentration (cmc* ), degree of counterion dissociation (g ), thermodynamic parameters, micellar mole fraction of ionic liquids, and interaction parameter (β) of the mixed system based on the different proposed models given in the literature. Further surface tension measurements have been carried out to confirm the value of cmc obtained via a conductivity study for all the studied systems at 298.15 K. Other surface parameters, such as surface tension at cmccmc ), surface pressure (ᴨcmc ), surface excess (Γmax ), and minimum area per molecule (Amin), have also been evaluated for both the systems.  相似文献   

15.
3‐Chloro‐2‐hydroxypropyl dimethyl dehydroabietyl ammonium chloride (CHPDMDHA) was synthesized from dehydroabietylamine (DHA) and epichlorodrin. The synthesis was done in three steps. First, DHA was transformed into N,N‐dimethyl dehydroabietyl amine (DMDHA) through Eschweiler‐Clarke Reaction. Second, the DMDHA was reacted with hydrochloric acid and translated into DMDHA hydrochloride. Third, the CHPDMDHA was obtained after the DMDHA hydrochloride had reacted with epichlorodrin and recrystallized using a solvent composed of ethyl acetate and ethanol. The critical micelle concentrations (CMC) of CHPDMDHA at 25 °C was found to be 2.56 × 10?4 mol L?1, and its surface tension at the CMC (γCMC) was determined to be 27.4 mN m?1; these data suggest that the surface activities of CHPDMDHA are better than those of benzalkonium chloride (BC), so that CHPDMDHA could be used as a good alternative to BC.  相似文献   

16.
N‐Dodecyl‐N,N‐di(2‐hydroxyethyl) amine oxide (C12DHEAO) and N‐stearyl‐N,N‐di(2‐hydroxyethyl) amine oxide (C18DHEAO) were synthesized with N‐alkyl‐diethanolamine and hydrogen peroxide. Their chemical structures were confirmed using 1H‐NMR spectra, mass spectral fragmentation and FTIR spectroscopic analysis. It was found that C12DHEAO and C18DHEAO reduced the surface tension of water to a minimum value of approximately 28.75 mN m?1 at concentration of 2.48 × 10?3 mol L?1 and 32.45 mN m?1 at concentration of 5.21 × 10?5 mol L?1, respectively. The minimum interfacial tension (IFTmin) and the dynamic interfacial tension (DIT) of oil–water system were measured. When C18DHEAO concentration was in the range of 0.1–0.5%, the IFTmin between liquid paraffin and C18DHEAO solutions all reached the ultra‐low interfacial tension. Furthermore, their foam properties were investigated by Ross‐Miles method, and the height of foam of C12DHEAO was 183 mm. It was also found that they showed strong emulsifying power.  相似文献   

17.
The critical micelle concentrations (cmc) of mixed systems comprising an amphiphilic drug amitriptyline hydrochloride and counterion‐coupled gemini surfactants 12‐6‐12, 14‐6‐14, or 16‐6‐16 [1,6‐bis(N,N‐alkyldimethylammonium) adipate] were determined using tensiometry. The results were analyzed in the light of different theoretical models from Rosen, Clint, Rubingh, and Motomura. The cmc values decrease with increasing mole fraction of surfactant (α1). The cmcid values (cmc value at ideal mixing conditions) also decrease with α1 but remain above the experimental cmc values. This means that the mixed micelles form as a result of attractive interactions. These interactions are also seen in surface excess concentration (Γmax) and minimum area per molecule (Amin) data: Γmax increases and Amin decreases. Both Rosen's and Rubingh's models indicate synergistic interactions (interaction parameter, βm and βσ, values are negative). The βm values are larger in magnitude than βσ for 14‐6‐14 and 16‐6‐16 systems, whereas the reverse is the case with 12‐6‐12 because the surfactant's short chain makes adjustment in the core difficult for both components.  相似文献   

18.
Kinetics of the anionic ring‐opening polymerization of octamethylcyclotetrasiloxane (D4) in bulk initiated by potassium isopropoxide was studied. Several promoters including N‐methyl‐2‐pyrrolidinone (NMP), N,N‐dimethylformamide (DMF), and diglyme were used. It is indicated that the reactions are first‐order in D4 during the initial stage of polymerization. The polymerization rate of D4 is influenced by a number of factors, such as the nature of promoters, the molar ratio of promoter to initiator (Cp/Ci ratio), and the reaction temperatures. With the use of NMP as promoter, the polymerization rate constant at 30°C is 10.482 h?1 with the Cp/Ci ratio equal to 3.0. As the Cp/Ci ratio increases, the polymerization rate constant increases sharply and the cyclic oligomers content in polymer decreases evidently. The back‐biting reaction that leads to the formation of decamethylcyclopentasiloxane (D5) occurred in the polymerization of D4. The rate of the D5 formation relatively to the rate of D4 conversion increases with the conversion of D4. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3510–3516, 2006  相似文献   

19.
Tuning physicochemical properties of aqueous surfactant solutions comprised of normal or reverse micelles by external additives is of utmost importance due to the enormous application potential of surfactant‐based systems. Unusual and interesting properties of environmentally benign ionic liquids (IL) make them suitable candidates for this purpose. To understand and establish the role of IL in modifying properties of aqueous gemini surfactants, we studied the effect of the IL, 1‐hexyl‐3‐methylimidazolium bromide ([Hmim][Br]) and 1‐octyl‐3‐methylimidazolium bromide ([Omim][Br]) on the properties of the aqueous cationic gemini surfactant 1,6‐hexanediyl‐α,ω‐bis(dimethyltetradecyl)ammonium bromide (14‐6‐14,2Br?). The behavioral changes were investigated by measuring the critical micelle concentration (CMC) using electrical conductance, surface tension, dye solubilization and fluorescence probe measurements at 298.15 K. It was observed that the CMC of 14‐6‐14,2Br? gemini surfactant decreases with addition of IL, thus favoring the micellization process. An increase in micellar size was observed at lower IL concentration using dynamic light scattering, with a decrease in aggregation number (Nagg) determined from fluorescence probe quenching measurements. It is noteworthy that the extent of modulation of the micellar properties is different for both the IL due to their structural differences. IL behave like electrolytes at lower concentrations and cosurfactants at higher concentrations and form mixed micelles with the cationic gemini surfactant showing an increase in Nagg.  相似文献   

20.
A series of cetyl alcohol based anionic bis‐sulfosuccinate gemini surfactants (BSGSCA1,4; BSGSCA1,6 and BSGSCA1,8) with different spacer lengths was prepared using dibromoalkanes. The surfactant structure was elucidated using elemental analysis, Fourier transform infrared spectroscopy (FT‐IR) and nuclear magnetic resonance spectroscopy (NMR). Surface tension measurements were used to determine the critical micelle concentration (CMC), the surface tension at the CMC (γCMC), surface pressure at the CMC (πCMC) and efficiency of adsorption (pC20). On the basis of surface studies, the CMC and γCMC decreases with increasing length of the spacer group. The micelle aggregation number, determined by fluorescence quenching studies, increases with increasing surfactant concentration above the CMC. The micropolarity in the micelle increases with increasing length of the spacer and decreases with increasing surfactant concentration.  相似文献   

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