Dimethylcetylammonium Bromide Research Articles

Enhanced Herbicidal Action of Clopyralid in the Form of a Supramolecular Complex with a Gemini Surfactant

Surfactants are often added to herbicidal formulations to improve the delivery of the herbicide into plants. In this study a new herbicidal formulation was formed based on the clopyralid with 0.01% gemini surfactant hexanediyl-1,6-bis(dimethylcetylammonium bromide) (16-6-16) as an adjuvant. The increase in the efficiency of the formulation was associated with the formation of a supramolecular surfactant–herbicide complex (SMC), which has improved wetting properties, provides high clopyralid concentration on the leaf surface, and has higher penetrating ability compared to surfactant-free clopyralid solutions. Comparison of the herbicidal action of clopyralid–16-6-16 SMC with two commercial formulations of the same concentration of clopyralid was performed using digital phenotyping of the model weed plant cocklebur (Xanthium strumarium). Based on the spectral indices NDVI (normalized differential vegetation index) and PSRI (plant senescence reflectance index) and key morphological indexes of the leaf angle, plant height, and leaf area, we showed that clopyralid formulations strongly affected the plants and that the strongest and most durable effect was exerted by the clopyralid–16-6-16 SMC formulation.

Selective separation of gold and palladium using the improved Gemini Micellar-Enhanced ultrafiltration

The aim of this study was to selectively separate precious metals such as gold and palladium from a binary solution using the Gemini micellar-enhanced ultrafiltration (GMEUF) process. The selectivity of this process was improved by adding the chelating agent ethylene diamine tetra-acetic acid (EDTA) to the solution. It means that one of these two metals can interact with the surface of Gemini micelles and reject by the membrane. The other metal must tend to bind to the ligand and enter the permeate stream. The effect of various parameters such as solution pH, operating pressure, flow rate, molar concentration ratio of the surfactant to the metal (S/M) and molar concentration ratio of the chelating agent to the metal (C/M) was investigated on the selective separation of these metals by a commercial polyethersulfone (PES) membrane and two Gemini surfactants. The rejection of gold and palladium in the optimal conditions of the above parameters reached the values of 90.2% and 21.4%, respectively, for the solutions containing N1-dodecyl-N1,N1,N2,N2-tetramethyl-N2-octylethane-1,2-diaminium bromide (CG12) micelles. In the presence of pentanediyl-1,5-bis (dimethyl cetyl ammonium bromide) (G5) micelles, these rejection values changed to 91.7% and 27.1%, respectively. The obtained results indicated a good selectivity in the separation of gold and palladium by the improved GMEUF process.

The micellization studies of cationic gemini surfactant, hexanediyl-1,6-bis(dimethylcetylammonium bromide solutions by conductometric, tensiometric, dye solubilisation, FTIR and 1H NMR: The influence of adenosine and temperature

Herein we report the effect of adenosine and temperature on the micellization of cationic gemini surfactant, hexanediyl-1,6-bis(dimethylcetylammonium bromide (16-6-16) solutions. The critical micelle concentration (CMC) of 16-6-16 was measured by the conductivity, surface tension measurements, fluorometric and dye solubilisation methods. An increasing trend of the CMC values was found with addition of adenosine (additive). With increasing the temperature, an increasing trend of CMC values was found (i.e., CMC value increases with increasing the temperature). The energetics (viz., standard Gibbs energy (ΔGm0), standard enthalpy (ΔHm0), and standard entropy (ΔSm0)) of micellization of 16-6-16 were evaluated. The evaluated energetics indicates less stability of the 16-6-16 solution in presence of adenosine. From the FTIR and 1H NMR data confirmed that there was no chemical reaction take place during the interaction between the gemini surfactant, 16-6-16 and adenosine.

Activity of Polyphenoloxidase in red Fuji Apples Promoted with Cationic Surfactant – Role of Surfactant Structure

Abstract In this study, we observed the activity of polyphenoloxidase (PPO) in red Fuji apples in the presence of single-chained surfactants (including cetyl trimethyl ammonium bromide (CTAB), and dodecyl trimethyl ammonium bromide (DTAB)) and gemini surfactants (pentamethylene-α,ω-bis(dodecyl dimethyl ammonium bromide), octamethylene-α,ω-bis(dodecyl dimethyl ammonium bromide, dodecamethylene-α,ω-bis(dodecyl dimethyl ammonium bromide), pentamethylene-α,ω-bis(cetyl dimethyl ammonium bromide), and octamethylene-α,ω-bis(cetyl dimethyl ammonium bromide)). It was found that all these surfactants enhanced the activity of PPO in a wide range of temperature at low content. When PPO was denatured by incubating at high temperature, the surfactants caused reactivation of PPO. Compared to the single-chained surfactants, the gemini surfactants increased PPO activity at a much lower concentration. Moreover, the single-chained surfactant and the gemini surfactant acted together to further increase PPO activity, and the synergistic effect reduced the amount of surfactant used. In addition, the Michaelis-Menten constant for PPO did not change in the presence of the surfactants, suggesting the active site should remain well with the surfactants.

Use of Gemini surfactant as emulsion interface microreactor for the synthesis of nitrogen-doped hollow carbon spheres for high-performance supercapacitors

A series of N-doped porous carbon materials with open interconnected mesoporous shells and various mesoscopic morphology were synthesized by using the cationic Gemini surfactant pentane-1,5-bis(dimethylcetyl ammonium bromide) as the soft template through a sol-gel method and the mechanism of interfacial reaction was explored. The controllable morphological structure (particle size, shell thickness and interconnected structure of internal cavities in carbon nanospheres) can be easily achieved by simply adjusting the volume of ethanol and the amount of cationic Gemini surfactant. The synthesized N-doped mesoporous hollow carbon spheres (NMHCSs) exhibit the characteristics of small and tunable particle size (30–140 nm), ultrahigh surface area (1215–1517 cm2 g−1) and large pore volume (1.12–3.22 cm3 g−1), open interconnected hierarchical mesoporous (5–20 nm), high proportion doping of heteroatoms N (4.16–6.74 at.%) and O (6.17–8.68 at.%). The representative NMHCSs as electrical double layer capacitors electrodes in 6 M KOH electrolyte display an excellent electrochemical specific capacitance (240 F g−1 at 0.2 A g−1), superb capacitance retention (161 F g−1 at 20 A g−1), and excellent cycle stability (92% capacitance retention at 10 A g−1 after 5000 cycles). This research develops a simple synthesis strategy for a series of N-enriched carbon materials which exhibit promising application prospects for high-performance supercapacitors.

Effects of silica nanoparticle on the solution properties of hydrophobically associating polymer based on acrylamide and β-cyclodextrin

Synthesis of a novel β-cyclodextrin-functionalized hydrophobically associating polyacrylamide named ASM was carried out using acrylamide (AM), cetyl dimethyl allyl ammonium bromide (SD-16) and modified β-cyclodextrin (M-β-CD) via free-radical copolymerization. Effective characterization methods, including FT-IR, 1H NMR and TGA, were adopted to evaluate ASM. Influences of SiO2 nanoparticle (nano-SiO2) on ASM solution properties were evaluated. The results showed that the addition of nano-SiO2 significantly increased the temperature resistance, salt tolerance and shear resistance of the ASM solution. It was found that ASM/SiO2 composite had 1.5 times higher viscosity than ASM in the range of 25–90 °C. The FT-IR data confirmed that the formation of hydrogen bond between silanol groups at surface of nano-SiO2 and amide group, hydroxyl group of M-β-CD in ASM molecule contributed to the improved performance. What’s more, viscoelastic test indicated that nano-SiO2 remarkably facilitated the cross-links among polymer molecules and enhanced the elasticity of ASM/SiO2 composite. Based on the enhanced oil recovery tests, the oil recovery could remarkably enhance 10.08% for composite versus only 6.56% for ASM.

Kinetic study of ninhydrin with chromium (III)‐glycylleucine in aqueous–alkanediyl‐α,ω‐bis (dimethylcetylammonium bromide) gemini surfactants

AbstractIn this article, we report kinetic study of ninhydrin with chromium (III)‐glycylleucine complex in aqueous–alkanediyl‐α,ω‐bis (dimethylcetylammonium bromide) gemini surfactants at different temperatures and pH. The experiments were monitored by using UV‐visible spectrophotometer. The study was run by maintaining pseudo‐first‐order condition ([ninhydrin] > > [Cr (III)‐Gly‐Leu]2+). Reactions were respective fractional‐ and first‐order paths, in ninhydrin and chromium‐glycylleucine complex. Conductometric technique has been used for critical micelle concentration (cmc) determination of 16‐s‐16 (spacer [s] = 4, 5, 6) gemini surfactants. Alkanediyl‐α,ω‐bis (dimethylcetylammonium bromide) surfactants were observed more effective on the study as compared with traditional monocationic cetyltrimethylammonium bromide (CTAB). With geminis, rate constant, kψ, rises up first (below cmc, part I) and becomes approximately fix (part II). In part III, kψ intensifies more at higher concentrations of gemini surfactants. The variation in rate in the presence of geminis has been elucidated by pseudo phase model.

Surfactant-polymer interaction: effect of hydroxypropylmethyl cellulose on the surface and solution properties of gemini surfactants

Interaction of a nonionic polymer hydroxypropylmethyl cellulose (HPMC) with the cationic gemini surfactants, ethane-1,2-diyl bis (N,N-dimethyl-N-hexadecylammoniumacetoxy) dichloride (16-E2-16), pentanediyl-1,5-bis (dimethylcetylammonium bromide) (16-5-16), hexanediyl-1,6-bis(dimethylcetylammonium bromide) (16-6-16), and the conventional surfactant (cetyltrimethylammonium bromide, CTAB) has been investigated by surface tension and rheology measurements. Stronger interaction of HPMC with the geminis as compared to the conventional surfactant is indicated by the values of physicochemical parameters which include the critical aggregation concentration (cac), critical micelle concentration (cmc), ΔG $$ {}_m^o $$ (standard Gibbs free energy of micellization), Γmax (maximum surface excess concentration at the air/solution interface), Amin (minimum area per surfactant molecule), and η (viscosity). Interaction between the surfactant and polymer in the mixed systems results in the formation of polymer-surfactant micelles; strength of the interaction is found to be dependent upon the nature of surfactant. On increasing the polymer concentrations, cac as well as cmc of the surfactant increases.

An intermittent amyloid phase found in gemini (G5 and G6) surfactant induced β-sheet to α-helix transition in concanavalin A protein

Surfactant-induced amyloid fibrillation has many implications in laboratory and industry. Previously, cetyltrimethylammonium bromide (CTAB; C19H42BrN) induced amyloid formation in concanavalin A (ConA) has been reported by authors (Khan, JM et al., 2016 A). In this work, cationic gemini surfactants pentanediyl‑1,5‑bis (dimethylcetylammonium bromide); 16-5-16 (G5), and hexanediyl‑1,6‑bis (dimethyl cetyl ammonium bromide); 16-6-16 (G6) were found to induce amyloid-like aggregation in ConA as studied with turbidity at 350 nm, Rayleigh scattering and Thioflavin T (ThT) binding assay and Far UV CD. The sizes of the aggregates were characterized with dynamic light scattering (DLS) and atomic force microscopy (AFM). Hydrodynamic radii (Rh) of the aggregates were found to be 74 nm and 122 nm with 50 μM of G5 and G6 respectively. Even at 7.5 μM, gemini surfactants seems disrupting hydrophobic pockets of ConA and result in aggregation. On the contrary, aggregation disappeared around 250 μM surfactant concentration with β-sheet → α-helix transition. The re-establishment of intra-molecular hydrogen bonding may have resulted in the formation of non-native α-helical structures. Alcohols, predominantly 2,2,2‑trifuloroethanol (TFE), have been reported to induce α-helices in β-sheet proteins by solvent engineering. There are very few reports of β-sheet to α-helix transition induced by non-alcoholic substances. Our lab is pioneer in reporting surfactant (CTAB) induced β-sheet to α-helix transition in ConA (Khan, JM et al., 2016 A). This is the first report of G5 and G6 gemini surfactant induced β-sheet to α-helix transition, as per our knowledge. ConA being apoptotic to cancerous cells and having potential therapeutic effect on hepatoma, the observations done in this work could be of immense interest in vesicular delivery of ConA.

Adsorption Properties of Gemini and Monomeric Cationic Surfactants on Sandstone and Silica Nanoparticles

The surface modification of pore throat by adsorption of surfactants is thought to have a positive effect on water flooding in low and ultralow permeability reservoirs. In this paper, Gemini cationic surfactants, containing 12 and 16 carbon alkyl chains(ethanediyl-1,2-bis(dimethyl dodecyl ammonium bromide) and ethanediyl-1,2-bis(dimethyl cetyl ammonium bromide), referred to as GC12 and GC16) and hexadecyl trimethyl ammonium bromide (CTAB) were used as modifying agents to investigate the effects of the surfactant concentration, adsorption time and temperature on static adsorption onto the surface of sandstone and silica nano particles (NPS). The results show that the equilibrium adsorption amount of GC16 on sandstone and NPS is higher than that of GC12 on sandstone and NPS with the same initial concentration of 0.225 mmol/L in solution at 45°C. It is found that the adsorption amounts of GC12 and GC16 decrease as the raise of temperature. The adsorption rate of surfactant on sandstone surface is slower than that of NPS. The equilibrium adsorption time of these surfactants on sandstone is 20 h, while the time of NPS is only 2 h. At 55°C, the static saturation absorption amount of GC12 is 210.56 μmol/g on NPS and 117.67 μmol/g on sandstone, while the amounts of CTAB on sandstone and NPS under static conditions are 1.18 times and 1.46 times of GC12, respectively. Considering the number of tail chain in a molecule of surfactant, the packing densities of Gemini surfactants on solid surface are higher than that of the single-tail surfactant (CTAB). Therefore, the adsorption rate and amount of surfactant are affected by the specific surface of solid particles, charged density, tail chain number and length of the cationic group.

Pineapple peel bromelain extraction using gemini surfactant-based reverse micelle – Role of spacer of gemini surfactant

Abstract In this study, the reverse micelles from gemini surfactants pentamethylene-α,ω-bis(dodecyldimethylammonium bromide), dodecamethylene-α,ω-bis(dodecyldimethylammonium bromide), pentamethylene-α,ω-bis(cetyl-dimethylammonium bromide) and octamethylene-α,ω-bis(cetyldimethylammonium bromide) were used to extract bromelain from pineapple peel. The extraction parameters including pH, ionic strength and surfactant content were studied. It was found that the reverse micelle from dodecamethylene-α,ω-bis (dodecyldimethylammonium bromide) could extract more active bromelain in a much wider range of pH, surfactant content and ionic strength than the reverse micelles from the other gemini surfactants, and the optimum activity recovery, purification fold and protein extraction efficiency with dodecamethylene-α,ω-bis (dodecyldimethylammonium bromide) were 160 %, 2.7 and 59 %, respectively. Pineapple peel accounts for the largest waste proportion of pineapple. This study investigated the effect of gemini surfactant structure on extraction efficiency of bromelain from pineapple peel by reverse micelle extraction, and hence, should be helpful for understanding the potency of gemini surfactant in protein extraction.

Density, dynamic viscosity, and kinematic viscosity studies of aqueous solution of a cationic gemini surfactant, hexanediyl-1,6-bis(dimethylcetylammonium bromide (16-6-16): Influence of electrolytes and temperature

In the present paper, we report density, dynamic viscosity and kinematic viscosity of a cationic gemini surfactant, hexanediyl-1,6-bis(dimethylcetylammonium bromide (16-6-16) aqueous solution in absence and presence of electrolytes at the temperature range from 393 to 343K. With increasing the temperature the density, dynamic viscosity and the kinematic viscosity of the pure gemini surfactant is decreasing; while increasing the concentration of gemini surfactant, 16-6-16 the values are increasing. In presence of electrolyte, an increasing trend was observed. However, with increasing the temperature (in presence of electrolyte), a similar decreasing trend was observed. The influence of metallic ion (co-ions) was found to be in the order: Li+<Na+<K+≅NH4+; whereas the influence of halide ion (counter ion) was found to be in the order: F−<Cl−<Br−<I−.

Interaction of triblock-copolymer with cationic gemini and conventional surfactants: A physicochemical study

ABSTRACTIn the current work, we have examined the interaction activities of Pluronic F-68 with cationic conventional, cetyltrimethylammonium bromide (CTAB), and gemini surfactant, pentanediyl-1, 5-bis(dimethylcetylammonium bromide), (16-5-16) by means of surface tension and conductivity measurements. The critical micelle concentration (cmc) values of pure 16-5-16 and CTAB have been evaluated tensiometrically and conductometrically, while the cmc values of pure F-68 and binary mixtures were determined only from the surface tension plots. Various interfacial and micellar parameters including surface excess concentration (Γmax), minimum area per molecule (Amin), surface pressure at cmc (πcmc), packing parameter (p), and interaction parameter (β) have been estimated and discussed in detail. Various thermodynamic parameters including Gibbs free energy of micellization (), standard free energy of adsorption at the air–water interface (), excess free energy of micellization (ΔGex), and molar free energy at the maximum adsorption achieved at cmc (Gmin) have been calculated.

Spectroscopic studies on the gemini surfactant mediated refolding of human serum albumin

Refolding of guanidinium hydrochloride (GdCl) denatured human serum albumin (HSA) using a combination of cationic gemini surfactants; pentanediyl-α,ω-bis(cetyldimethylammonium bromide) (C16H33(CH3)2N+–(CH2)5–N+(CH3)2C16H33)2Br− designated as G5 and methyl- β-cyclodextrin, is attempted in the present study. The studies were carried out in an aqueous medium (pH 7.4) using dynamic light scattering (DLS), circular dichroism (CD) and fluorescence spectroscopy. A careful study of the DLS data indicates that against the hydrodynamic radius (Rh) of 3.5nm in native human serum albumin (HSA), hydrodynamic radius after attempting refolding by simple dilution increases to 33.8nm. The large Rh values of the diluted protein sample is associated with the formation of aggregates as dilution is an aggregation prone pathway. Hydrodynamic radii equal to 5.4nm, that is very near to the native protein (3.5nm), is obtained on the sequential addition of G5 and methyl- β-cyclodextrin to the denatured protein. The results obtained from the multi-technique approach are associated with the presence of two charged head-groups and two hydrocarbon tails in the gemini surfactants resulting in very strong electrostatic and hydrophobic interactions.The present study suggests that gemini surfactants may be utilised in the protein refolding studies and may prove to be inexpensive and efficient folding agents.

Influence of Amine-Based Cationic Gemini Surfactants on Catalytic Activity of α-Chymotrypsin

The α-chymotrypsin activity was tested in aqueous media with the presence of novel cationic amine–based gemini surfactant, with different spacer chain lengths and head group size, and also compared with the cationic cetyltrimethylammonium bromide (CTAB) and cetyltriphenylphosphonium bromide (CTPB) surfactants and aqueous buffer only. The p-nitrophenyl acetate (PNPA) hydrolysis rate was monitored in the presence of the surfactant concentration at 30°C. Most of these gemini surfactants gave higher catalytic activity as compared to cationic CTAB and CTPB. The highest superactivity was measured in the presence of gemini 16-12-16, [dodecanediyl-1,12-bis(cetyldimethylammonium bromide)] surfactant at pH 7.5. The catalytic reaction follows the Michaelis–Menten mechanism. The catalytic rate constants, kcat, show the same profile that the catalytic affinity; KM being enhanced with increasing space chain length. The results are favorable for considering that the amine-based gemini surfactant influences more than both the aqueous and cationic micellar media.

Self-Association, Mixed Micellization, and Thermodynamic Studies of Sodium Dodecyl Sulfate (SDS) and Hexanediyl-1,6-Bis(Dimethylcetylammonium Bromide) (16-6-16)

The self-association, mixed micellization, and thermodynamic studies of a conventional anionic surfactant, sodium dodecyl sulfate (SDS), and a cationic gemini surfactant, hexanediyl-1,6-bis(dimethylcetylammonium bromide) (16-6-16), have been reported in the present investigation. The critical micelle concentration (CMC) of pure and mixed (SDS, 16-6-16, and SDS + 16-6-16) surfactants was measured by electrical conductivity and dye solubilization measurements. The CMC values were found to increase with increasing temperature. The thermodynamic parameters (viz., the standard Gibbs energy (), the standard enthalpy change (), and the standard entropy change ()) of the micellar and mixed micellar systems were evaluated.

Effect of (chloride salt) electrolytes on the mixed micellization of (equimolar) a cationic gemini (dimeric) surfactant and a cationic conventional (monomeric) surfactant

ABSTRACTHerein we report the effect of (chloride salt) electrolytes on the mixed micellization of (equimolar) a cationic gemini (dimeric) surfactant, hexanediyl-1,6-bis(dimethylcetylammonium bromide) (16-6-16), and a cationic conventional (monomeric) surfactant, cetyltrimethylammonium bromide (CTAB) in aqueous solutions. In absence and presence of (chloride salt) MCl (where M˭Li, Na, and K) electrolytes, the critical micelle concentration (CMC) of mixed (16-6-16 + CTAB) surfactants was measured by surface tension measurements. With increasing the concentration of electrolyte, the CMCs were increasing. The surface properties and the thermodynamic parameters of the mixed micellar systems were also evaluated. From these evaluated thermodynamic parameters, it was found that in presence of electrolyte the stability of the mixed micellar system is more.

Micellization and mixed micellization of cationic gemini (dimeric) surfactants and cationic conventional (monomeric) surfactants: Conductometric, dye solubilization, and surface tension studies

ABSTRACTIn the present study, we have investigated the self-association, mixed micellization, and thermodynamic studies of a cationic gemini (dimeric) surfactant, hexanediyl-1,6-bis(dimethylcetylammonium bromide (16-6-16)) and a cationic conventional (monomeric) surfactant, cetyltrimethylammonium bromide (CTAB). The critical micelle concentration (CMC) of pure (16-6-16 and CTAB) and mixed (16-6-16+CTAB) surfactants was measured by electrical conductivity, dye solubilization, and surface tension measurements. The surface properties (viz., C20 (the surfactant concentration required to reduce the surface tension by 20 mN/m), ΠCMC (the surface pressure at the CMC), Γmax (maximum surface excess concentration at the air/water interface), Amin (the minimum area per surfactant molecule at the air/water interface), etc.) of micellar (16-6-16 or CTAB) and mixed micellar (16-6-16+CTAB) surfactant systems were evaluated. The thermodynamic parameters of the micellar (16-6-16 and CTAB) and mixed micellar (16-6-16+CTAB) surfactant systems were also evaluated.

Dipeptide Glycyl-Glycine (Gly-Gly)–Ninhydrin Reaction: Effect of Alkanediyl-α,ω-bis(dimethylcetylammonium bromide) (16-s-16, s = 4, 5, 6) Gemini Surfactants on the Reaction Rate

AbstractThe present work concerns with the effect of alkanediyl-α,ω-bis(dimethylcetylammonium bromide) gemini surfactants on the reaction rate of ninhydrin with glycyl-glycine. The spectra showed peaks at 400 nm and 570 nm in aqueous and aqueous–micellar media indicating the formation of the same product. Under pseudo-first-order conditions of excess ninhydrin, the reaction followed an irreversible first- and fractional-order kinetics with respect to [Gly-Gly] and [ninhydrin]. Also, the rate constants (kψ) increases and leveling-off regions are found with [geminis] (akin to conventional cetyltrimethylammonium bromide, CTAB), a third-region of increasing kψ is observed at higher [geminis]. The kinetic data in gemini micellar medium have been examined with the pseudo-phase model.

Amino Acid‐Functionalized Calix[4]Resorcinarene Solubilization by Mono‐ and Dicationic Surfactants

AbstractPoorly water‐soluble calix[4]resorcinarenes modified with amino acid (Ala, Val) at the upper rim formed a water‐soluble mixed system with micelles of monocationic surfactants cetyltrimethylammonium bromide, cetyldimethyl(2‐hydroxyethyl)ammonium bromide, and dicationic (gemini) surfactants, alkanediyl‐α,ω‐bis(dimethyltetradecylammonium bromides (14‐s‐14, where s = 2, 4, or 6). UV–Vis and DLS methods demonstrated that the micellar systems of surfactant/functionalized calix[4]resorcinarene underwent structural changes within a relatively narrow concentration range followed by changes in solubilization capacity and polydispersity. Gemini surfactants and monocationic/gemini mixed surfactant systems were provided selectivity in their interaction with calix[4]resorcinarene depending on the bulkiness of the substituent at the upper rim of calix[4]resorcinarene, gemini surfactant spacer length, and mixed micelles. These systems represent a direction to create biocompatible water‐soluble functionalized calix[4]resorcinarene composition and may open perspectives in designing organized systems with controllable properties.