Retracted: Synthesis,Characterization, and Surface Activities of Polymeric Cationic Thiol Surfactants in Aqueous Medium

A series of cationic polyurethane surfactants [PQ_8-18] were synthesized by the reaction of alkyl bromoacetate (namely: octyl-, decyl-, dodecyl-, tetradecyl-, hexadecyl-, and octadecyl bromoacetate) as quaternizing agents and modified polyurethane contains tertiary amine species. Modified polyurethane was prepared by the reaction of toluene diisocyanate (TDI) and triethanol amine monomercaptoacetate. The chemical structures of the prepared surfactants were confirmed using elemental analysis, Fourier transform infrared spectroscopy (FTIR), and Proton nuclear magnetic resonance (¹H NMR) spectroscopy. The molecular weight measurements of the prepared polymers showed that the segments of each polymer contain average 10 units of the urethane-triethanol amine mercaptoacetate. The surface activities of the prepared surfactants including: surface tension (γ), effectiveness ( π_cmc), concentration at micelle formation (CMC), efficiency (Pc₂₀), maximum concentration at the interface (Γ_max), and the average area occupied by each surfactant molecule at the interface at equilibrium ( A _min) of surfactants solutions were established at 25°C. The surface tension and the critical micelle concentration values of the prepared surfactants were gradually decreased by the gradual increase of their alkyl chain length. The prepared cationic surfactants showed efficient activity as inhibitors for dissolution of carbon steel in an acidic medium and also as a biocide against the growth of bacteria, fungi, and yeast.     

Surface Parameters and Biological Activity of <Emphasis Type="Italic">N</Emphasis>-(3-(Dimethyl Benzyl Ammonio) Propyl) Alkanamide Chloride Cationic Surfactants

Three cationic surfactants containing amide groups were prepared by quaternization of dimethylaminopropylamine with benzyl chloride. FTIR and ¹H-NMR spectroscopy were used to confirm the chemical structure of the prepared cationic surfactants. The surface parameters were estimated using surface tension measurements at three different temperatures. The prepared cationic surfactant showed a lower CMC than conventional cationic surfactants. Thermodynamic parameters of adsorption and micellization depend mainly of alkyl chain length and temperature. The adsorption process is more favorable than micellization. The biological activity of the three surfactants was estimated using inhibition zone showing that amidoamine cationic surfactants have good activity and the surfactants C12Bn is the most effective one.     

Gemini Cationic Surfactants: Synthesis and Influence of Chemical Structure on the Surface Activity

Three cationic gemini surfactants were synthesized and characterized using different methods. Their surface activities were measured using surface and interfacial tension measurements. The effect of the spacer chain length on the surface activity, emulsification power and interfacial tension was studied. The thermodynamic parameters showed the tendency towards micellization and adsorption. The results showed that longer spacers increased the micellization tendencies of the surfactants, while shorter spacers increased the adsorption tendency at the air–water interface.     

Surface and Biocidal Properties of Gemini Cationic Surfactants Based on Propoxylated 1,6-Diaminohexane and Alkyl Bromides

Two new classes of gemini cationic surfactants—hexanediyl-1,6-bis[(isopropylol) alkylammonium] dibromide {in the abbreviation form: C_nC₆C_n[iPr-OH] and C_nC₆C_n[iPr-OH]₂; alkyl: C_nH_{2n + 1} with n = 9, 10, 12 and 14}—have been synthesized by interaction of alkyl bromides with N,N′-di-(isopropylol)-1,6-diaminohexane and N,N,N′,N′-tetra-(isopropylol)-1,6-diaminohexane. The surface tension, electrical conductivity, and dynamic light scattering (DLS) techniques were used to investigate the aggregation properties of the gemini cationic surfactants in aqueous solution. The formation of critical aggregates at two concentrations in an aqueous solution from obtained gemini cationic surfactants were determined via the tensiometric method. Thus, these gemini cationic surfactants start to form aggregates at concentrations well below their critical micelle concentrations (CMC). The surface properties and the binding degree (β) of the opposite ion were tested against the length of the surfactant hydrocarbon chain and the number of the isopropylol groups in the head group. By applying the DLS technique, it was explored that how the number of isopropylol groups in gemini cationic surfactants with C₁₂H₂₅ chain affects the sizes of micelles at concentrations greater than CMC. It was discovered that the obtained gemini cationic surfactants have a biocidal character.     

Synthesis,Surface Property and Antimicrobial Activity of Cationic Gemini Surfactants Containing Adamantane and Amide Groups

A series of novel cationic gemini surfactants, namely 1,3-adamantanedicarboxylic acid bis(alkyldimethyl-3-ammoniopropyl amide) dibromide designated as [Ad-2(amC _n )] (n = 12, 14, 16), containing adamantane, two amide groups, and two hydrocarbon chains, were synthesized from 1,3-adamantanedicarboxylic acid. The surface-active properties of the surfactants were investigated through surface tension and electrical conductivity measurement. A series of thermodynamic parameters such as standard free energy \(\left( {\Delta G^\circ_{\text{m}} } \right)\) , enthalpy \(\left( {\Delta H^\circ_{\text{m}} } \right)\) , and entropy \(\left( {\Delta S^\circ_{\text{m}} } \right)\) of micellization were evaluated from electrical conductivity measurements in the temperature range from 288 to 308 K. The micellization for [Ad-2(amC _n )] is entropy-driven at low temperature and enthalpy-driven at high temperature. Further, the antimicrobial activity of the synthesized gemini surfactants against both Gram-positive and Gram-negative bacteria was also investigated, and this study showed that the compound [Ad-2(amC₁₂)] has excellent antibacterial activity against all studied bacteria.     

季铵盐双子表面活性剂的合成和表面活性

以吗啉和溴代烷为原料,合成了两种季铵盐双子表面活性剂(m-6-m,m=10,12),并用IR和1HNMR表征了其结构。测得28℃时,12-6-12和10-6-10的表面张力(γCMC)分别为26.45 mN/m和25.55 mN/m;临界胶束浓度(CMC)分别为1.0 mmol/L和3.1 mmol/L;pC20值分别为3.48和3.03;比表面过剩(Γmax)分别为2.72×10-6mol/m2和2.80×10-6mol/m2;分子最小截面积(Amin)分别为0.611 nm2和0.593 nm2。结果表明,该季铵盐双子表面活性剂与相同离子头基及烷基链的单季铵盐表面活性剂相比,CMC低一个数量级,γCMC相差不大。     

Structure and Biological Behaviors of Some Metallo Cationic Surfactants

In this study, different cationic surfactants were prepared by esterification with bromoacetic acid of different fatty alcohols, i.e., dodecyl, tetradecyl and hexadecyl species. The products were then reacted with diphenyl amine, and the resulting tertiary amines were quaternized with benzyl chloride to produce a series of quaternary ammonium salts. The metallocationic surfactants were prepared by complexing the cationic surfactants with nickel and copper chlorides. Surface tension of these surfactants were investigated at different temperatures. The surface parameters including critical micelle concentration (CMC), maximum surface excess (Γ _max), minimum surface area (A _min), efficiency (PC₂₀) and effectiveness (π _CMC) were studied. The thermodynamic parameters such as the free energy of micellization ( $\Updelta G_{\text{mic}}^{^\circ }$ ) and adsorption ( $\Updelta G_{\text{ads}}^{^\circ }$ ), enthalpy ( $\Updelta H_{\text{m}}^{^\circ }$ ), ( $\Updelta H_{\text{ads}}^{^\circ }$ ) and entropy ( $\Updelta S_{\text{m}}^{^\circ }$ ), ( $\Updelta S_{\text{ads}}^{^\circ }$ ) were calculated. FTIR spectra and ¹H-NMR spectra were obtained to confirm the compound structures and purity. In addition, the antimicrobial activities were determined via the inhibition zone diameter of the prepared compounds, which were measured against six strains of a representative group of microorganisms. The results indicate that these metallocationic surfactants exhibit good surface properties and good biological activity on a broad spectrum of microorganisms.     

Synthesis,Characterization and Surface Activities of Cationic Polysaccharide (Aloe) Schiff Base Surfactants

Synthesis of cationic polysaccharide (Aloe) Schiff base surfactants was described and their chemical structures were confirmed by using FTIR spectroscopic, H‐NMR and UV analysis. The surface activities of these surfactants were measured, including surface tension, critical micelle concentration, effectiveness, efficiency, maximum surface excess and minimum surface area at 25 °C, interfacial tension and emulsification power at 25 °C. Adsorption and micellization free energies of these amphiphiles in their solutions showed a good tendency towards adsorption at the interfaces.     

Synthesis,Surface and Antimicrobial Activities of Novel Cationic Gemini Surfactants

A series of novel cationic gemini surfactants [C_nH_2n+1–O–CH₂–CH(OH)–CH₂–N⁺(CH₃)₂–(CH₂)₂]₂·2Br^? [ 3a (n = 12), 3b (n = 14) and 3c (n = 16)] having a 2‐hydroxy‐1,3‐oxypropylene group [?CH₂–CH(OH)–CH₂–O–] in the hydrophobic chain have been synthesized and characterized. Their water solubility, surface activity, foaming properties, and antibacterial activity have been examined. The critical micelle concentration (CMC) values of the novel cationic gemini surfactants are one to two orders of magnitude smaller than those of the corresponding monomeric surfactants. Furthermore, the novel cationic gemini surfactants have better water solubility and surface activity than the comparable [C_nH_2n+1–N⁺(CH₃)₂–(CH₂)₂]₂·2Br^? (n‐4‐n) geminis. The novel cationic gemini surfactants 3a and 3b also exhibit good foaming properties and show good antibacterial and antifungal activities.     

Synthesis,Surface Activity and Aggregation Behavior of Novel Gemini Pyridinium Amphiphiles

A series of novel pyridinium cationic gemini amphiphiles, 3,3′-(carbonyldiimino)bis (1-n-alkylpyridinium) dibromides, having octyl, decyl, dodecyl, tetradecyl alkyl chains were synthesized. The surface properties and aggregation behavior in aqueous solution were evaluated by surface tension, dynamic light scattering (DLS), and transmission electron microscopy (TEM) measurement. The adsorption at the air/solution interface of all the compounds were quantitative described using the Frumkin model, and the effect of alkyl chain length on surface activity and aggregate behavior was analyzed. It was found that all the gemini amphiphiles possess surface activity and low critical micellization concentration (CMC) values. The values of log CMC depended linearly on the carbon number of the alkyl chains, but the surface tension at the CMC (γ_cmc) showed a minimum for the compound with dodecyl chains. Combinations of DLS and TEM observations showed the existence of vesicles with a broad size distribution in aqueous solution. Meanwhile, vesicles formed below the CMC could be a possible reason for the observed deviation of surface tension curves from the Frumkin model.     

Synthesis, Characterization and Biological Activity of Sugar-Based Gemini Cationic Amphiphiles

Two series of gemini cationic surfactants were synthesized based on glucose and fructose molecules. Their chemical structures were confirmed using micro-elemental analysis, mass spectral fragmentation and FTIR spectroscopic analysis. The surface activities of these gemini amphiphiles were measured, including surface tension (γ), critical micelle concentration (CMC), effectiveness (π _cmc), efficiency (pC₂₀), maximum surface excess (Γ_max) and minimum surface area (A _min) at 25 °C. Adsorption and micellization free energies of these amphiphiles in their solutions showed a good tendency towards adsorption at the interfaces. The biological activity of the synthesized gemini amphiphiles showed good inhibition at concentrations of 1, 2.5 and 5 mg/mL. The synthesized amphiphiles showed antimicrobial activity on gram-positive and gram-negative bacteria and antifungal activity equal to or comparable to commercially available controls. The discussion rationalized the antimicrobial activities of these amphiphiles with the surface activity and the adsorption parameters. In addition, the effect of sugar nuclei was discussed based on the chemical structure of the bacterial and fungal cell membranes.

Synthesis and Evaluation of Novel Amido-Amine Cationic Gemini Surfactants Containing Flexible and Rigid Spacers

New amido‐amine‐based cationic gemini surfactants with flexible and rigid spacers and different hydrophobic tails were synthesized and characterized. These gemini surfactants were prepared by a modified procedure through amidation of long chain carboxylic acids using 3‐(dimethylamino)‐1‐propylamine followed by treatment with halohydrocarbons. The effect of the trans and cis conformation of the spacer double bond was investigated by means of critical micelle concentration, surface tension reduction, and thermal stability. The short‐term thermal stability of the gemini surfactants was assessed using thermogravimetric analysis (TGA) and the long‐term thermal stability was examined by a unique approach based on structure characterization techniques including NMR (¹H and ¹³C) and FTIR analysis. TGA results demonstrated excellent short‐term thermal stability since no structure degradation was observed up to 200 °C. Structural characterization revealed impressive long‐term thermal stability of the gemini surfactants with no structure decomposition after exposing them to 90 °C for 10 days. The critical micelle concentration of gemini surfactants was found to be in the range of 0.77 × 10^?4–3.61 × 10^?4 mol L^?1 and corresponding surface tension (γ_CMC) ranged from 30.34 to 38.12 mN m^?1. The surfactant with the trans conformation of spacer double bond showed better surface properties compared to the surfactant with the cis conformation of spacer double bond. Similarly, increasing surfactant tail length and spacer length resulted in decreasing CMC values. Moreover, bromide counterion showed improved surface properties compared to chloride counterion.     

Surface Activity Properties and Aggregation Behaviors of Partially Fluorinated Gemini Surfactants in Aqueous Solution

The surface activity and aggregation behavior of partially fluorinated gemini surfactant N,N′‐bis(3‐perfluorohexyl‐2‐hydroxypropyl)‐N,N′‐dipropanesulfonylhexylenediamine (N‐6‐Sul) was studied by surface tension, resonance light scattering and fluorescence spectra measurements. The critical micelle concentration (CMC) values obtained by the three methods are in good agreement. The surface activity parameters such as the effectiveness of surface tension reduction (Π_cmc), the maximum surface excess concentration (Γ_max) and the minimum surface area per molecule (A_min) were obtained through surface tension curves. The effects of pH, inorganic salts and temperature on the surface activity were also investigated. The morphology and size of the aggregates of N‐6‐Sul were examined by transmission electron microscopy (TEM). The results show that the partially fluorinated gemini surfactant N‐6‐Sul has many advantages such as high surface activity, low CMC value, great salt tolerance and temperature resistance.     

Synthesis and Surface Properties of Novel Quaternary Ammonium Gemini Surfactants with Polar Head Groups Containing 2-Hydroxypropyl Moieties

The purpose of this paper is to comprehend in-depth the effect of the surfactant structure on its and physicochemical properties such as surface/interfacial properties, foam stability, wettability, and biodegradability. To this end, quaternary ammonium Gemini surfactants, alkanediyl-α,ω-bis[(2-hydroxypropyl)dodecylammonium] dibromide (abbreviated as C_m-n-C_m[iso-Pr(OH)]₂ with m = 12, 14 and n = 2, 3, 4) were synthesized via substitution and quaternization reactions, and their chemical structures were characterized by Fourier transform infrared (FT-IR) and nuclear magnetic resonance (¹HNMR) spectroscopies. The results showed that with the decrease of the spacer length, the surface tension was reduced more strongly, and with the increase of the alkyl tail length, micelles were more easily formed. Besides, the highest surface activity of C₁₄-2-C₁₄[iso-Pr(OH)]₂ was observed by increasing NaCl concentration to 200 g L⁻¹. The temperature had a great influence on thermodynamic parameters of the adsorption and micellization. The interfacial tension between 0.26 g L⁻¹ C₁₄-2-C₁₄[iso-Pr(OH)]₂ solution and oil could reach 0.022 mN m⁻¹. An elongation of the spacer chain in C₁₄-n-C₁₄[iso-Pr(OH)]₂ was unfavorable to foam stability. Besides, the oil-wetted core, which was aged in 0.6 g L⁻¹ C₁₄-2-C₁₄[iso-Pr(OH)]₂ solution, exhibited more hydrophilicity. C_m-n-C_m[iso-Pr(OH)]₂ surfactants produced higher biodegradable rates in river water (≥ 90% after 28 days) than the biodegradable surfactant of international recommendation (71% after 28 days) at 30 °C.     

Synthesis,Characterization and Evaluation of the Surface Active Properties of Novel Cationic Imidazolium Gemini Surfactants

New imidazolium gemini surfactants were synthesized by reaction of epichlorohydrin with long chain fatty alcohols furnishing products 2-(alkoxymethyl)oxirane followed by their subsequent treatment with imidazole resulting in the formation of 1-(1H-imidazol-1-yl-3 alkoxy)propane-2-ol which on subsequent treatment with 1,2-dibromoethane and 1,3-dibromopropane resulted in the formation of title gemini surfactants:1,2-bis(1(3-alkoxy-2-hydroxypropyl)-1H-imidazol-3-ium)ethane bromide (7), 1,3-bis(1(3-alkoxy-2-hydroxypropyl)-1H-imidazol-3-ium)propane bromide (8), 1,2-bis(1(3-alkoxy-2-hydroxypropyl)-1H-imidazol-3-ium)ethane bromide (9), 1,3-bis(1(3-alkoxy-2-hydroxypropyl)-1H-imidazol-3-ium)propane bromide (10), 1,2-bis (1(3-alkoxy-2-hydroxypropyl)-1H-imidazol-3-ium)ethane bromide (11) and 1,3-bis (1(3-alkoxy-2-hydroxypropyl)-1H-imidazol-3-ium)propane bromide (12). Their identification was based on IR, ¹H-, ¹³C-NMR, DEPT, COSY and mass spectral studies. Their surface active properties were also evaluated on the basis of surface tension and conductivity measurements.     

Novel Imidazolium-Based Gemini Surfactants: Synthesis, Surface Properties, Corrosion Inhibition and Biocidal Activity Against Sulfate-Reducing Bacteria

Three novel imidazolium-based gemini surfactants had been synthesized and characterized using different spectroscopic techniques. The surface properties of the synthesized surfactants were determined using surface tension measurements at 20 °C. The surface parameters including critical micelle concentration (CMC), π _CMC, Pc₂₀, Γ_max and A _min were determined. The synthesized compounds were evaluated as corrosion inhibitors for carbon steel in 0.5 M HCl solution using the weight loss and polarization techniques. The biological activity of these surfactants was evaluated against sulfate reducing bacteria using most probable number method. The results indicate that the synthesized compounds have good surface properties and are proper corrosion inhibitors for low carbon steel, with a high inhibition efficiency observed around their CMC. These compounds exhibit a significant biocidal activity against sulfate reducing bacteria.     

Preparation,Characterization and Properties of Novel Cationic Gemini Surfactants with Rigid Amido Spacer Groups

A series of novel cationic gemini surfactants with rigid amido groups inserted as the spacers, named C ₁₂ ‐PPDA‐C ₁₂ , C ₁₄ ‐PPDA‐C ₁₄ and C ₁₆ ‐PPDA‐C ₁₆ , were synthesized by a two‐step reaction with dimethyl terephthalate, N,N‐dimethyl propylene diamine and alkyl bromide as raw materials. The chemical structures of the prepared compounds were confirmed by IR, ¹H and ¹³C NMR and element analysis. Surface activity properties of the synthesized compounds were investigated by surface tension, electrical conductivity and fluorescence. Increasing the number of carbon atoms in the hydrophobic alkyl chain, decreased the critical micelle concentration (CMC), surface tension at the CMC and the minimum surface area. Other relevant properties including foaming ability and emulsion stability were investigated. The results indicated that the synthesized gemini surfactants possess good surface properties, emulsifying properties and steady foam properties.     

双子表面活性剂的结构特点与表面活性

双子型表面活性剂由于极性头基区域的键合,阻抑了极性头之间的斥力,突破了传统表面活性剂的结构概念,具有比传统表面活性剂高得多的表面活性,现有的研究数据表明并联结构的双子表面活性剂具有比串联结构的双子表面活性剂高的降低表面张力的能力。     

阳离子双子表面活性剂的应用研究进展

介绍了阳离子双子表面活性剂近年来在新材料制备、抗腐蚀、杀菌、三次采油、织物染整、生物技术及造纸工业等方面的应用。     

Synthesis and Properties of New Cleavable Cationic Surfactants Containing Carbonate Groups

A novel series of cleavable alkyltrimethylammonium surfactants with different hydrocarbon chain lengths (C8–16) were synthesized. A carbonate break site inserted between the polar head and the hydrocarbon chain makes these compounds hydrolyzable. The reagents used are renewable, (bio)degradable, or reusable. The hydrolysis of these cleavable surfactants will lead to the generation of fatty alcohols and choline, which is an essential biological nutrient. The surface activities in aqueous solution of the synthesized carbonates fulfill the requirement of being good surfactants. In addition, the cleavable compounds containing n-decyl and n-dodecyl chains showed similar or higher antimicrobial activities when compared to a non-cleavable analog.