Synthesis and Surface Properties of Novel Cationic Gemini Surfactants

A series of novel cationic gemini surfactants, p-[C _n H_2n+1N⁺(CH₃)₂CH₂CH(OH)CH₂O]₂C₆H₄·2Cl^? [A(n = 12), B(n = 14) and C(n = 16)], containing a spacer group with two flexible and hydrophilic groups (2-hydroxy-1,3-propylene) on both sides of a rigid and hydrophobic group (1,4-dioxyphenylene) has been synthesized by the reaction of hydroquinone diglycidyl ether with N,N-dimethylalkylamine and N,N-dimethylalkylamine hydrochloride. Their surface-active properties have been investigated by surface tension measurement. The critical micelle concentration (cmc) values of the synthesized cationic gemini surfactants are one order of magnitude lower than those of their corresponding monomeric surfactants (C _n H_2n + 1N⁺(CH₃)₃·Cl^?). Both the cmc and surface tension at the cmc (γ_cmc) of A are lower than those of p-[C₁₂H₂₅N⁺(CH₃)₂CH₂]₂C₆H₄·2Cl^? (D). The novel cationic gemini surfactants A and B also show good foaming properties.     

Synthesis and combined properties of novel fluorinated cationic surfactants derived from hexafluoropropylene dimer

Three novel fluorinated surfactants with branched short fluorinated tails as hydrophobic groups, ammonium oxide as polar groups are prepared. Surface tension measurement shows that these fluorinated surfactants are ideal compounds to design new formulations in fire-fighting field.     

Effect of Organic Solvents on the Electrodeposition of Copper from Acidified CuSO4

Using Guerbet tetradecyl alcohol C₁₄GA (synthesized by Guerbet reaction using 1-heptanol as raw material) as intermediate, sodium Guerbet tetradecyl polyoxyethylene ether sulfates [C₁₄GA(EO)_nS, n = 1, 2, 4] were obtained through following steps: synthesizing Guerbet tetradecyl polyoxyethylene ether alcohols [C₁₄GA(EO)_nH, n = 1, 2, 4] by Williamson reaction, then esterifying with chlorosulfonic acid so as to form Guerbet tetradecyl polyoxyethylene ether alcohol sulfates [C₁₄GA(EO)_nSO₃H, n = 1, 2, 4], and finally neutralizing with sodium hydroxide; while sodium Guerbet tetradecyl sulfate(C₁₄GAS) was synthesized only through esterifying and neutralizing reactions. The structures of these anionic surfactants were determined by infrared, nuclear magnetic resonance, and element analysis. The surface activity of these surfactants was studied by means of surface tension. The results have shown that these surfactants possess higher surface activity than the common surfactant C₁₂H₂₅OSO₃Na. Branched-tail structure coming from Guerbet alcohol makes the anionic surfactant (C₁₄GAS) have higher critical micelle concentration (CMC) and better effectiveness in lowering the interface tension between air and water than their linear counterpart (C₁₄H₂₉OSO₃Na). Introducing oxyethyene group into the place between head group and tail group of the surfactant molecule with branched tail can lower the CMC, γ_cmc, and Krafft point. And the effectiveness for reducing the CMC, γ_cmc, Γ_max, and Krafft point of surfactant increased with the increase of oxyethylene group number (n = 1, 2, 4). The relationship between the molecular structure and surface activity of surfactant is discussed.     

Effect of Oxyethylete Units on Adsorption and Micellization Properties of Novel Benzene Sulfonate Surfactants

The surface tension and fluorescence spectra of sodium octyl-[ω-octyloxy-poly(oxyethylene)]-yl-benzene sulfonates (APE_nBS) aqueous solutions have been investigated by Wilhelmy plate method and intrinsic probe methods, respectively to study the effect of EO units on their properties. It was discovered that the surface performance of these surfactants was greatly outstanding: the values of critical micelle concentration (CMC) reached to be of the order of magnitude of 10^?5 mol/L, the values of surface tension at CMC, γ_CMC, were between 25.79 to 31.02 mN/m, and the effectiveness and efficiency of surface tension reduction were excellent. The introduction of oxyethylene units to the surfactant molecule evidently improved the solubility of APE_nBS. With the increase in EO units, the CMC slightly changed after the first decreased. On the other hand, the surface excess concentration at saturation, Γ _max, decreased after the first increased and γ_CMC increased after the first decreased accordingly. The CMC determined by fluorescence spectra of intrinsic probe method were accorded with the CMC measured by surface tension method. The aggregation number N, characterized by quenching the fluorescence spectra with methyl viologen (MV²⁺) as the extrinsic quencher, gradually decreased first (from 0 to1) and then slightly changed (from 1 to 4) with increasing EO chain length. So we concluded that the appropriate number of EO units was the key factor to get the best physicochemical properties of APE_nBS.     

Adsorption and thermodynamic properties of dissymmetric gemini imidazolium surfactants with different spacer length

A series of dissymmetric gemini imidazolium surfactants with different spacer length ([C_mC_sC_nim]Br₂, m + n = 24, m = 12, 14, 16, 18; s = 2, 4, 6) were synthesized and characterized by ¹H NMR and ESI-MS spectroscopy. Their adsorption and thermodynamic properties were investigated by the surface tension and electrical conductivity methods. Consequently, the surface activity parameters (cmc, γ_cmc, π_cmc, pC₂₀, cmc/C₂₀, Γ_max, A_min) and thermodynamic parameters (ΔG_m^θ, ΔH_m^θ, ΔS_m^θ) were obtained. The effects of the dissymmetry (m/n) and the spacer length (s) on the surface activity and micellization process of surfactants have been discussed in detail.     

Synthesis and solution properties of ionic liquid-type polysiloxane bola surfactants

Three novel ionic liquid (IL)-type polysiloxane bola surfactants (ATPS-MA, ATPS-EA, and ATPS-PA) were designed and synthesized using a two-step method. Their chemical structures were characterized by Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (¹H NMR) spectroscopy. Their surface activity and aggregation behavior in aqueous solution were systematically investigated by surface tension measurements, transmission electron microscopy (TEM), and dynamic light scattering (DLS). Surface activity measurement results indicated that the γ_CMC of the three IL-type polysiloxane surfactants are under 25 mN m^?1, and much lower than those of conventional IL hydrocarbon bola surfactants due to the introduction of siloxane group at the end of the hydrophobic chains. TEM and DLS analyses results indicated that the three surfactants can self-assemble into spherical micelles with a range from 50 to 300?nm, indicating potential uses as model systems for biomembranes and vehicles for drug delivery.     

Synthesis and Properties of Aromatic Side Chained N‐Acyltaurate Surfactants

A series of anionic N‐acyltaurate surfactants, side chain containing aromatic nucleus (abbreviated as SAATT), were synthesized via Williamson reaction, hydrolyzation, and acylation. Krafft temperatures and surface properties of these surfactants at 30°C, that is, critical micelle concentration, cmc, surface excess concentration, Γ_max, surface area demand per molecule, A _min, efficiency in surface tension reduction, pC₂₀, effectiveness in surface tension reduction, π_cmc, and cmc/C₂₀ parameter were determined. It was shown that these surfactants exhibit good solubility which was confirmed by measuring Krafft temperature. The cmc of SAATT was much smaller than that of conventional surfactants with similar effective carbon numbers, and shifted to lower concentration with increasing hydrocarbon chain length. In addition, the γ_cmc decreased with decrease in Γ_max. The pC₂₀ and the cmc/C₂₀ got larger with the increase in hydrocarbon chain length. From the fluorescence intensity ratios of I ₁ (373 nm) and I ₃ (384 nm) using pyrene as a probe, it was indicated that the molecules of SAATT formed loose micelles with a broad size distribution.     

Novel Cationic Gemini Surfactants Based on Piperazine: Synthesis,Surface Activity,and Foam Ability

A series of novel Gemini surfactants C_n-pi-C_n with piperazine moiety as spacer was synthesized and characterized by IR, ¹H NMR, and mass spectra. Their surface activities were evaluated by surface tension, electrical conductivity, and steady-state fluorescence. The obtained results indicated that the synthesized Gemini surfactants exhibited lower critical micelle concentration (cmc) and surface tension (γ_cmc) compared with traditional surfactants. The steady-state fluorescence measurement and electrical conductivity were recorded to demonstrate the accuracy of cmc values. In addition, the micellization was evaluated using conductivity measurement in the temperature range of 298–308 K. The foamability and foam stability of these Gemini surfactants were also examined. In which, the Gemini surfactant with the shortest chain (C₁₂) showed the best foamability but the poorest foam stability. Hydrophile–lipophile balance and emulsifying ability were studied and a comparatively poor emulsifying ability displayed.     

Syntheses and properties of ethoxylated double‐tail trisiloxane surfactants containing a propanetrioxy spacer

A new type of ethoxylated double‐tail trisiloxane surfactants containing a propanetrioxy spacer of the general formula ROCH₂CH(OR)CH₂O(CH₂CH₂O)_xCH₃ [R = Me₃SiOSiMe(CH₂)₃OSiMe₃, x = 8.4, 12.9, 22] has been synthesized. Their structures were characterized by ¹H‐NMR, ¹³C‐NMR and ²⁹Si‐NMR spectroscopy. The critical micelle concentration (CMC) values of these double‐tail trisiloxane surfactants were at the level of 10⁻⁵ mol l⁻¹, and the surface tension values of their aqueous solutions at CMC were in the range of 21‐24.9 mN m⁻¹. Only the double‐tail trisiloxane surfactant with average ethoxy units of 8.4 ( 1P ) possesseda good spreading ability (SA) value. Its SA values of aqueous solutions (5.0 × 10⁻³ mol l⁻¹) on parafilm and Ficus microcarpa leaf surfaces were more than 15 (within 10 min) and 13 (within 3 min), respectively. The trisiloxane surfactant 1P was also found to have the strongest hydrolysis resistant ability among all of the double‐tail trisiloxane surfactants prepared. Its aqueous solutions were stable for 130 days in an acidic environment (pH 4.0) and 59 days in an alkaline environment (pH 10.0) with surface tension values less than 23 mN m⁻¹. It is suggested that this surfactant can be used as a wetting agent or spreading agent in certain extreme pH environments. Copyright © 2011 John Wiley & Sons, Ltd.     

Interaction of Nonionic Surfactant Triton-X-100 with Ionic Surfactants

The interaction in two mixtures of a nonionic surfactant Triton-X-100 (TX-100) and different ionic surfactants was investigated. The two mixtures were TX-100/sodium dodecyl sulfate (SDS) and TX-100/cetyltrimethylammonium bromide (CTAB) at molar fraction of TX-100, α_TX-100 = 0.6. The surface properties of the surfactants, critical micelle concentration (CMC), effectiveness of surface tension reduction (γ_CMC), maximum surface excess concentration (Γ_max), and minimum area per molecule at the air/solution interface (A _min) were determined for both individual surfactants and their mixtures. The significant deviations from ideal behavior (attractive interactions) of the nonionic/ionic surfactant mixtures were also determined. Mixtures of both TX-100/SDS and TX-100/CTAB exhibited synergism in surface tension reduction efficiency and mixed micelle formation, but neither exhibited synergism in surface tension reduction effectiveness.     

Synthesis and Evaluation of Surface Activity of Gemini Borate Surfactants Based on Glucose Moiety

A series of Gemini borate surfactants were synthesized based on glucose molecule. Their chemical structures were confirmed using ¹H-NMR,¹³C nuclear magnetic resonance (NMR), and mass spectroscopy. The surface activities of these Gemini amphiphiles were measured, including surface tension (γ), critical micelle concentration (CMC), effectiveness (II_cmc), efficiency (pC₂₀), maximum surface excess (Γ_max), and minimum surface area (A_min) at different temperatures 25, 35, and 45°C either in pure water or in water–ethanol mixture (10%). Also, thermodynamic data including free energy, entropy, and enthalpy changes (ΔS, TΔS, ΔH) for adsorption at the air–water interface and also for micellization in surfactant solutions were calculated.     

Micellization of fluorinated amphiphiles

New cationic fluorinated surfactants and new types of fluorinated surfactants having fluorocarbon–hydrocarbon hybrids, dimeric and polymeric structure have been synthesized recently. Their synthesis requires many steps and consequently requires much time and high expense. Since the fluorinated surfactants have unusual molecular aggregation properties, ¹⁹F-NMR, novel fluorescence probes and cryo-transmission electron microscope techniques have been applied to study their aggregation behaviour in aqueous systems. Their unique characteristics are summarized as follows: (1) the dissolution process from solid state to dissolved aggregate state requires a very long time for the long chain fluorinated surfactants under thermodynamic equilibrium. The equilibration time can be reduced at higher temperatures; (2) interfacial properties and critical micelle concentration (CMC) are influenced by the nature of the hydrophobic terminal groups (CF₃− or HCF₂−); (3) the fluorocarbon functionality can make it possible even for single-chain amphiphiles to form vesicles or lamellar structures; (4) the hybrid surfactant made of both hydrocarbon and fluorocarbon chains showed a life time of 2.0×10⁻³ s for the exchange rate between the monomeric and the micellar states at the CMC and moreover, these detergents can cosolubilize fluorocarbon–hydrocarbon mixed solubilizates.     

Synthesis and Properties of Novel Cationic Triazolium Gemini Surfactants

New type of triazolium Gemini surfactants were synthesized by reaction of epichlorohydrine with long-chain fatty alcohols namely cetyl alcohol and oleyl alcohol furnishing product 2-(alkoxymethyl)oxirane followed by the their subsequent treatment with triazole resulting in the formation of 1-(1,2,4-triazole)-3-alokoxypropane-2-ol which on reaction with 1,6-dibromohexane resulted in the formation of triazolium-based cationic Gemini surfactant. Their formation was confirmed by IR spectroscopy. Surface tension values were used to determine the critical micelle concentration (CMC), minimum area per molecule (A_min) at air?water interface, Gibbs free energy of adsorption (ΔG_ads), the maximum surface excess concentration (Γ_max), and other parameters. The inhibition behavior of dimeric surfactant on the corrosion of carbon steel (CS) in 1 N H₂SO₄ aqueous medium was studied at 30°C. Performance tests like dispersion capability, foaming power and stability, emulsifying power, and wetting ability were determined. The obtained results show that dispersion capability, foaming power, foaming stability, and emulsifying ability are very good. The wetting power of synthesized surfactants is quite better.     

Synthesis and surface active properties of a gemini-type surfactant linked by a quaternary ammonium group

In this study, cationic surfactants having multi-hydroxyl groups were synthesized by the condensation reaction of octadec-9-enyl glycidyl ether and methyl amine followed by the quaternization with dimethyl sulfate. The structure of the product was elucidated by ¹H-NMR and FT-IR. The minimum critical micelle concentration (CMC) and surface tension achieved using C18:1-BHDM surfactant were 1.24?×?10^?4?mol/L and 43.36 mN/m, respectively. The interfacial tensions measured between 1 wt% surfactant solution and n-decane were found to be in the same order of magnitude as those exhibited between micellar solutions and nonpolar hydrocarbon oils. The contact angle measurement result suggests that C18:1-BADM is the best wetting agent among the surfactants tested during this study. It has been observed that the results for foam stability measurement are consistent with those of CMC and contact angle. That is, the percentage of foam volume decrease has been observed to increase with an increase in number of hydroxyl group.     

Solubilization Behaviors of Nonpolar Substrates Using Double Tailed Cationic Surfactants

A series of double hydrophobic tails of N-methyl diethanolammonium bromide cationic surface active agents were synthesized. Their chemical structures were elucidated using different analytical tools including elemental analyses, FTIR, mass fragmentation, and ¹H-NMR spectroscopy. Their surface parameters including critical micelle concentration (CMC), effectiveness (π _CMC ), efficiency (Pc ₂₀), maximum surface excess (Γ _max ), and minimum surface area (A _min ) were calculated. The behaviors of the synthesized molecules in their solutions were discussed based on the data of surface parameters, micellization and adsorption thermodynamics at 25°, 40°, and 55°C. The experimental data of surface activity showed that these molecules are tends to form micelles in the bulk of their solutions at lower temperatures. On contrarily, they prefer to adsorb at higher temperatures. The synthesized cationic surfactants were used as solubilizing agent for nonpolar substrate (paraffin oil) at 25°C. The results of solubilization measurements showed good ability for the used surfactants towards solubilizing paraffin oil in aqueous medium. The results showed that the chemical structure of the solubilizate plays an important rule in its solubilization. Several factors were found to influence the extent of solubilization including: number of alkyl chains within surfactant molecule, symmetry of molecules and chain length of hydrophobic parts. The results were rationalized by the Kraft point and HLB values of the used surfactants. Furthermore, solubilization curves showed the steady state solubilization of each surfactant used.     

Syntheses of cardanol-based cationic surfactants and their use in emulsion polymerisation

Six quaternary ammonium salts were designed and synthesised with moderate to high yields in three steps, based on cardanol, a low-cost and abundant renewable resource. The new ammonium salts can act as reactive surfactants due to their having both a hydrophilic ammonium group and a hydrophobic unsaturated alkyl chain. The gemini surfactants with a linker of a linear saturated aliphatic hydrocarbon chain exhibited a relatively low CMC value (≤ 0.2 mmol L^?1) and surface tension (≤ 27 mN m^?1), signifying that this kind of amphiphile exhibited good surface active properties. The photo-active gemini surfactant with critical micelle concentration (CMC) of 0.05 mmol L^?1 was used successfully as the sole emulsifier in the emulsion polymerisation of methyl methacrylate (MMA). In addition, a benzyl bromide-containing surfactant can act as both an atom transfer radical polymerisation (ATRP) initiator and an emulsifier in an activator generated by the electron transfer atom transfer radical polymerisation (AGET ATRP) of MMA in emulsion. The value of the number-average molecular mass of the resulting cardanol-end poly(methyl methacrylate) (PMMA) is M_n,GPC = 45.1 kDa, with polydispersity of 1.39.     

Synthesis and Amphiphilic Behavior of N,N‐Bis‐glucosyl‐1,5‐benzodiazepin‐2,4‐dione

Abstract

Glucosyl‐1,5‐benzodiazepin‐2,4‐diones were synthesized in order to study the influence of the glucidic moiety on the amphiphilic behaviour. The glucosyl groups include 6‐deoxy‐D‐glucopyranos‐6‐yl and 6‐deoxy‐3‐O‐R‐D‐glucopyranos‐6‐yl (R = n ? C _n H _2n+1; n = 1, 8, 10 and 12). Variation in the length of the hydrocarbon chain allowed comparison of such amphiphilic data as water solubility (Sw) and surface tension (γ) values. At 25°C, the glucopyranosyl benzodiazepines with R = H and CH₃ show a higher water solubility than the starting 1,5‐benzodiazepin‐2,4‐diones. Some other glucidic benzodiazepine derivatives with an appropriate alkyl chain at C‐3 carbon of the D‐glucopyranose present a variable hydrosolubility and surface tension γ values close to 43 to 46 mN · m^?1 at the corresponding saturation. Moreover, according to preliminary tests, these compounds seem to show a better affinity for the blood brain barrier.     

Synthesis and properties of Alkyl α-D-Galactopyranoside

Alkyl α-D-galactopyranosides are sugar-based nonionic surfactants, and it is necessary to research their structure–property relationships since it is not quite clear that the change of the alkyl chain length has effects on a series of physicochemical properties. Here, alkyl α-D-galactopyranosides were prepared by galactose and alcohols through three steps including acetylation, coupling with alcohols in the presence of a catalyst stannic chloride, and deprotection. Furthermore, their water solubility and other properties were investigated. Alkyl α-D-galactopyranosides (4a ～ 4e, n = 6 ～ 10) were water soluble, and their dissolution process in water was an endothermic process. Nonyl α-D-galactopyranoside (4d) showed excellent foaming ability and foam stability. Octyl α-D-galactopyranoside (4c) had the strongest emulsifying ability for toluene and nonyl α-D-galactopyranoside (4d) had the strongest emulsifying ability for rapeseed oil. The critical micelle concentration (CMC) values and surface tension at the CMC were decreasing with increasing alkyl chain length. Their standard free energy of adsorption (ΔG_ads) was more negative than their standard free energy of micellization (ΔG_mic). The moisture-absorption abilities were weakening with increasing alkyl chain length. Alkyl α-D-galactopyranosides (4a ～4f) were thermally stable below 280°C. Alkyl α-D-galactopyranosides (4c ～4f) had the optical texture of the thermotropic liquid crystal smectic A phase.     

Adsorption and Micellization Properties of Novel Heterodouble‐Chained N‐Acyltaurate Surfactants

A set of heterodouble‐chained N‐acyltaurate surfactants (abbreviated as m+nP‐T, where m and n were carbon numbers of alkyl chain; P was phenyl; T was taurate) were synthesized. The novel amphiphiles contained sodium taurine as hydrophilic moiety and two different hydrocarbon chains as hydrophobic moiety. One was a long alkyl chain, and the other had an aromatic residue. Their surface properties were determined by Wilhelmy‐plate method, and micellization properties were investigated by fluorescence spectra of extrinsic probe and intrinsic probe. It was found that these surfactants showed some aberrant properties. It was difficult to obtain the equilibrium surface tension and critical micelle concentration (cmc) for the surfactants with two long chains. Pyrene was solubilized in micelle at concentration above cmc, and the fluorescent intensity ratio of the first vibronic peak (373 nm) to the third vibronic peak (383 nm) of pyrene decreased gradually. The aggregation number N, characterized by quenching the phenoxyl residue with methyl viologen (MV²⁺) as the extrinsic quencher, gradually increased with increasing surfactant concentration. These indicated that more and more molecules packed in a micelle with increasing concentration.     

Synthesis and properties of nonylphenol-substituted dodecyl sulfonate

Nonylphenol-substituted dodecyl sulfonate (C₁₂-NPAS) was synthesized via sulfonation-alkylation-neutralization using 1-dodecene, SO₃, and nonylphenol as raw materials. The properties such as surface tension, interfacial tension (IFT), wettability, foam properties, and salinity tolerance of C₁₂-NPAS were systematically investigated. The results show that the critical micelle concentration (CMC) of C₁₂-NPAS was 0.22?mmol?·?L^?1 and the surface tension at the CMC (γ_CMC) of C₁₂-NPAS was 29.4 mN/m. When compared with the traditional surfactants sodium dodecyl benzene sulfonate (SDBS), sodium dodecyl sulfate (SDS), and linear alkylbenzene sulfonate (LAS), the surface properties of C₁₂-NPAS were found to be superior. The IFT between Daqing crude oil and a weak-base alkaline/surfactant/polymer (ASP) oil flooding system containing 0.1?wt% of C₁₂-NPAS can reach an ultralow level of 2.79?×?10^?3 mN/m, which was lower than that found for the traditional surfactant heavy alkylbenzene sulfonate (HABS). The salinity and hardness tolerance of C₁₂-NPAS were much stronger than those found for conventional surfactants, petroleum sulfonate, and LAS. C₁₂-NPAS also shows improved wetting performance, foamability, and foam stability.