Quaternary Ammonium Surfactants Research Articles

Virucidal Coatings Active Against SARS-CoV-2

Three types of coatings (contact-based, release-based, and combined coatings with both contact-based and release-based actions) were prepared and tested for the ability to inactivate SARS-CoV-2. In these coatings, quaternary ammonium surfactants were used as active agents since quaternary ammonium compounds are some of the most commonly used disinfectants. To provide contact-based action, the glass and silicon surfaces with covalently attached quaternary ammonium cationic surfactant were prepared using a dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride modifier. Surface modification was confirmed by attenuated total reflection infrared spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy, and contact angle measurements. The grafting density of the modifier was estimated by XPS and elemental analysis. To provide release-based action, the widely used quaternary ammonium cationic disinfectant, benzalkonium chloride (BAC), and a newly synthesized cationic gemini surfactant, C18-4-C18, were bound non-covalently to the surface either through hydrophobic or electrostatic interactions. Virus titration revealed that the surfaces with combined contact-based and release-based action and the surfaces with only release-based action completely inactivate SARS-CoV-2. Coatings containing only covalently bound disinfectant are much less effective; they only provide up to 1.25 log10 reduction in the virus titer, probably because of the low disinfectant content in the surface monolayer. No pronounced differences in the activity between the flat and structured surfaces were observed for any of the coatings under study. Comparative studies of free and electrostatically bound disinfectants show that binding to the surface of nanoparticles diminishes the activity. These data indicate that SARS-CoV-2 is more sensitive to the free disinfectants.

Study on the synthesis of nanosheets petal-shaped ZSM-5 Zeolites

In this work, a novel strategy for hydrothermal synthesis of nanosheets petal-shaped ZSM-5 zeolites was introduced. The experimental results indicated that the nanosheets petal-shaped ZSM-5 zeolites exhibited a higher specific surface area and more abundant acid sites. Under the synergistic crystallization effect of ethanol and seeds, the addition of CTAB promoted the growth of the layered structure, and the introduction of trace amounts of seeds effectively inhibited the growth of mordenite in a high alkalinity environment, reducing the crystallization time to 48 hours. More importantly, the petal-shaped ZSM-5 zeolites exhibited excellent MTP (Methanol-to-Propylene) catalytic performance, with methanol conversion maintained above 97.8 % for 80 hours and a maximum propylene selectivity of 49.1 %. This paper proposes an Ethanol-Seed-CTAB synthesis method for producing petal-shaped ZSM-5 zeolite with a unique morphology. This approach does not require the use of complex gemini quaternary ammonium surfactants in the synthesis process, greatly promoting the application and dissemination of nanosheets zeolites.

Wormlike Micellar Glycerol Solutions Formed from a Double-Tailed Surfactant with Two Quaternary Ammonium Head Groups.

Herein, a quaternary ammonium surfactant with dual heads and tails, N1,N1,N1,N3,N3-pentamethyl-N3-(3-(2-tetradecylhexadecanamido)propyl)propane-1,3-diaminium dibromide, abbreviated as Di-C14-N2, was synthesized. For the first time, clear observation of aggregate structures formed by surfactants in pure glycerol systems was achieved using cryogenic transmission electron microscopy (cryo-TEM). The system's rheological properties were analyzed using both steady-state shear and oscillatory rheological measurements. The lubricating efficiency of the Di-C14-N2 glycerol solution was assessed for its tribological properties using a tribological wear tester, white light interferometer, and scanning electron microscope. In glycerol, Di-C14-N2 formed long wormlike micelles, which resulted in a glycerol solution with the zero-shear viscosity of 1013 Pa·s at 90 mM, which is the most viscous glycerol system up to now. The system displayed distinct rheological properties from the aqueous system, as evidenced by two intersections in the loss and storage moduli. The formed wormlike micelles in glycerol lead to a significant alteration in the viscoelasticity of the system, thus endowing the Di-C14-N2 glycerol solution with potential as an eco-friendly lubricant. The friction coefficient of the system was found to be 23% lower and the wear rate was 83% lower than that of pure glycerol after the addition of Di-C14-N2. This demonstrates that the addition of Di-C14-N2 greatly improves the frictional properties of pure glycerol. This study offers the possibility of directly observing the aggregate structures formed by surfactants in pure glycerol systems. It contributes to the exploration of the self-assembly behavior of surfactants in nonaqueous polar media, thereby aiding in a deeper understanding of the correlation between molecular structure, mesoscale structure, and macroscopic properties.

Surface activity, aggregation behaviour and wettability of mixtures of perfluorobranched short-chain gemini quaternary ammonium surfactant and hydrocarbon anionic surfactants in dilute solution

The hydrophobic and oleophobic properties of perfluorobranched short chains are similar to those long chain fluorocarbons (fluorocarbon chain length ≥ 7), and their environmentally friendly properties make them good alternatives to traditional perfluorooctyl derivatives. For this purpose, a novel perfluorinated branched short chain quaternary ammonium gemini surfactant (PBFS) with high surface activity was synthesized, and the surface properties, aggregation behavior, wetting performance and adsorption performance of the complex system of PBFS and sodium octyl sulfate (SOS) were systematically studied. PBFS exhibited superior surface activity in aqueous solution with the critical micelle concentration (CMC) of 0.1667 mmol/L and the corresponding surface tension (γCMC) of 20.17 mN/m. Moreover, despite the fact that the mixing of PBFS and SOS was not ideal, the two still had the good synergistic effect: the CMC of the compounding solution was reduced to 0.0072 mmol/L and γCMC was 16.01 mN/m when the compounding ratio (CF: CH) was 1:8. And the composite solution could completely wet low surface energy polytetrafluoroethylene (PTFE) plates at 1 mmol/L, and could also wet PTFE plates at extremely low concentrations (0.0625 mmol/L), showing good wetting performance.

Chain Friction and Lubrication Balanced Ultra-Tough Polyacrylates With Wide-Span Switchable Stiffness for Strain-Programmable Deformation.

Natural mollusks perform complex mechanical actions through reversible large-strain deformation and stiffness switching, which are challenging to achieve simultaneously in synthetic materials. Herein, it is shown that a set of polyacrylates designed according to a chain friction and lubrication balanced strategy showsultra-stretchability (λ up to 324), high resilience (near 100% recovery at strain ≥ 100), and wide-span stiffness switching (up to 2073 times). The typical emulsion polymerization method and casting technique are adopted to fabricate the polyacrylate films. Quaternary ammonium surfactants are used as the emulsifier and reserved in the polymer matrix to enhance the chain segment lubrication with their long alkyl group but improve the whole chain friction through the formation of nano-eutectics. These polyacrylates undergo multimodal mechanical responses, including temperature- or time-programmed deformation and load-bearing like artificial muscles. This molecular design principle and synthetic method provide a robust platform for the fabrication of ultra-tough polymers for soft robots with multiple customized functions.

Effect of hydrophilic group structure on the properties of fluorinated surfactants with the same hydrophobic skeleton

Fluorinated surfactants are composed of hydrophilic and hydrophobic groups, so the properties of fluorosurfactants are also affected by the combination of these two groups. However, there is little studies on the effect of the structure of hydrophilic groups on the fluorosurfactants properties. This paper reported the synthesis of a novel quaternary ammonium surfactant (BPAF-OH) with branched fluorocarbon short chains. To investigate the effect of hydrophilic group structure on the performance of fluorinated surfactants, the properties of BPAF-OH were compared with two fluorinated surfactants (BPAF-IEt and BPAF-SMA, which have the same hydrophobic skeleton as BPAF-OH). Experimental results had shown that for these three surfactants, the hydrophilic group structures had the relatively small impact on the thermal stability of fluorinated surfactants. In contrast, the hydrophilic group structures had the greater influence on the surface activities: BPAF-OH had the best surface activity with the critical micelle concentration (CMC) of 6.00 × 10−3 mmol/L, and the surface tension (γCMC) of 15.96 mN/m. Furthermore, the hydrophilic group structures had the certain influence on the thermodynamic parameters, aggregation behaviour and wettability of fluorine surfactants.

Surface activity, wettability and foam properties of quaternary ammonium surfactants with C-F/Si-H double hydrophobic backbone

This paper reported the synthesis of a novel quaternary surfactant (PFAS-Si) containing the C-F/Si-H double hydrophobic skeleton and the surface properties of its aqueous solution, which were investigated in comparison with those of the aqueous solutions of the fluorosurfactant (PFAS-IEt) and silicone surfactant (TMSAC) with similar hydrophobic chain structures. The critical micelle concentration (CMC) and the corresponding surface tension value (γCMC) of the PFAS-Si solution were 0.0612 mmol/L and 21.02 mN/m, respectively, which indicated that the PFAS-Si could substantially reduce the surface tension of water, and showed excellent surface activity. Meanwhile, the thermodynamic parameters of the micellization process, aggregation behavior, wettability, and foam properties of PFAS-Si solutions were systematically investigated. On the TEM negative staining photographs, it can be clearly seen that the aggregates of PFAS-Si in aqueous solution exhibit hollow spherical vesicles. In addition, the PFAS-Si solution exhibited superb wettability, and could achieve wetting of PTFE sheets at a very low concentration (0.168 mmol/L). Not only that, the PFAS-Si solution also had excellent foaming ability and foam stability. This work provided a new preparation idea for the development of high-performance specialty surfactants.

(Invited) Controlling Electric Fields and Hydration at Electrochemical Junctions Using Surfactants

Tuning the electrostatics and the water structure at the nm and sub-nm scales are two important frontiers towards the broader goal of controlling reactivity at interfaces. Surfactants offer a way to influence both the electrostatics and hydration of an electrochemical interface. Here we report measurements of local electric fields generated between layers of surfactants and an electrode without application of an external potential. We estimate the value of the electric field by measuring the vibrational frequency shift of a well-defined Stark probe that is adsorbed on the electrode. The field generated by the common quaternary ammonium surfactants in aqueous media is estimated to be in the order of 1 V/nm. We show that modest quantities of surfactants (50 mM) can produce polarizing fields similar to those produced by an electrode poised at -0.8 V vs. Ag/AgCl. Furthermore, we show that under electrochemical conditions, surfactants offer a way of modulating the water content near the electrode. In a mixture of water and DMSO, there are two forces that act upon the surfactants to drive them to the interface: they hydrophobic forces and the electrostatic forces from the electrode. We measure the surfactants at the interface as a function of these variables using surface enhanced IR spectroscopy, and arrive at quantitative comparisons between these two effects. These results help in understanding the design principles of modifying interfacial reactions via tailored surfactants.

Impact of hydroxyethyl headgroup on long-chain quaternary ammonium cationic surfactants: Solubility, surface activities, self-assembly behaviors, and rheological properties

The incorporation of hydroxy groups into long-chain quaternary ammonium surfactants can enhance their solubility and confer other desirable properties; however, the systematic investigation on the solution properties and the influence of molecular structures was less documented. In this work, two saturated C18-tailed quaternary ammonium surfactants with dual hydroxyethyl moieties, namely N,N-bis(2-hydroxyethyl)-N-methyloctadecan-1-aminium iodide (HEOAI) and N,N-bis(2-hydroxypropyl)-N-methyloctadecan-1-aminium iodide (HPOAI), were designed and synthesized. We investigated and compared their Krafft temperature (Tk), surface activities, self-assembly behaviors, and rheological properties. Our findings demonstrate that the introduction of hydroxyethyl groups dramatically improves the solubility and surface activities. The Tk of HEOAI and HPOAI is approximately 50 °C lower than that of the corresponding surfactant octadecyl trimethylammonium iodide. Both surfactants exhibit lower critical micelle concentration and equilibrium surface tension compared to those of corresponding conventional quaternary ammonium surfactant. This should be ascribed to the formation of hydrogen bonds between hydroxyl groups and water molecules. Moreover, HPOAI shows even better solubility and surface activities than HEOAI does. Additionally, the presence of two more methyl groups for HPOAI enhances its ability to form worm-like micelles in pure water. However, HEOAI shows better salt and temperature resistance for maintaining stability of worm-like micelles. A solution containing 50 mM HEOAI with 10 % NaCl exhibits temperature tolerance up to around 80 °C, indicating potential application as fracturing fluid for shallow and medium oil/gas reservoirs. These findings contribute to designing surfactants with improved solubility and diverse properties.

Bacterial dealkylation of benzalkonium chlorides in wastewater produces benzyldimethylamine, a potent N-nitrosodimethylamine precursor

N-nitrosodimethylamine (NDMA) is a carcinogenic disinfection byproduct that forms during chloramine disinfection of municipal wastewater effluents which are increasingly used to augment drinking water supplies due to growing water scarcity. Knowledge of wastewater NDMA precursors is limited and the known pool of NDMA precursors has not closed the mass balance between precursor loading, precursor NDMA yield, and formed NDMA. Benzalkonium chlorides (BACs) are the most prevalent quaternary ammonium surfactants and have antimicrobial properties. The extensive utilization of BACs in household, commercial and industrial products has resulted in their detection in wastewater at elevated concentrations. We report the formation of a potent NDMA precursor, benzyldimethylamine (BDMA) from the biodegradation of BACs during activated sludge treatment. BDMA formation and NDMA formation potential (FP) were functions of BAC and mixed liquor suspended solids concentration at circumneutral pH, and the microbial community source. Sustained exposure to microorganisms reduced NDMA FP through successive dealkylation of BDMA to less potent precursors. BAC alkyl chain length (C8 – C16) had little impact on NDMA FP and BDMA formation because chain cleavage occurred at the C–N bond. Wastewater effluents collected from three facilities contained BDMA from 15 to 106 ng/L, accounting for an estimated 4 to 38 % of the NDMA precursor pool.

Interaction, Surface Activity, and Application of Mixed Systems of Alcohol Ether Sulfate Anionic Surfactants with Multiple Ethylene Oxide Groups and Gemini Quaternary Ammonium Surfactant.

The surface activities and application properties for the mixtures of cationic surfactants tetramethylene-1,4-bis[N,N-bis(hydroxypropyl)-hexa/decyloxypropylammonium] bromide (GC10-P) and tetramethylene-1,4-bis[N,N-bis(hydroxyethyl)-hexa/decyloxypropylammonium] bromide (GC10-E) and anionic surfactant isomeric sodium fatty alcohol ether sulfates (iso-AE9S) were investigated using both the tensiometry and the conductometry. The interaction parameters and thermodynamic micellization parameters of GC10-P/iso-AE9S and GC10-E/iso-AE9S mixtures were evaluated by Clint-Rubingh and Motomura theoretical models. When the mole fraction of α1 for GC10-P/iso-AE9S mixed system was 0.2, the critical micelle concentration (CMC) reached a minimum of 1.61 × 10-4 mol/L, and the minimum critical micelle concentration of the GC10-E/iso-AE9S mixed system is 2.67 × 10-5 mol/L at α1 = 0.6. The CMC value of the mixed system is 1-2 orders of magnitude lower than that of any single component. The results indicate that the synergistic effects of the investigated mixed systems (evaluated by βm) are in order of GC10-P/iso-AE9S < GC10-E/iso-AE9S, with maximum βm values of -17.98 and -9.78, respectively. The change in zeta potential indicates that the poly(ethylene oxide) chain has weakened the charge density of the hydrophilic headgroup of the anionic surfactant. The interfacial tension at the oil-water interface in the mixed system of anionic/cationic surfactants is lower than that of any single component, exhibiting a higher interfacial activity. The mixed system exhibits a decreased contact angle and superior wetting ability over any single component, and it also enhances foam performance, emulsification performance, and degreasing performance.

Polycomplexes to modulate bactericidal activity of cetylpyridinium bromide

Cetylpyridinium bromide, a quaternary ammonium surfactant, was electrostatically complexed with an excess of anionic polymers such as biodegradable sodium alginate or non-biodegradable sodium polyacrylate. The binding of surfactant with alginate delivered polymer–surfactant complexes capable of killing both more surfactant-sensitive Escherichia coli and less surfactant-sensitive Pseudomonas aeruginosa bacteria, while the binding with acrylate gave complexes active only against Escherichia coli. The results obtained show a way for adjustment of the antimicrobial formulation to a specific pathogen to be destroyed.

Influence of pH on spectroscopic and interfacial features of phenol in aqueous cetrimonium bromide solutions of different concentrations

Phenol is an aromatic compound with toxic effects on the environment and living organisms. Cetrimonium bromide (CTAB) is a cationic, quaternary ammonium surfactant, constituent in industrial formulations, and is employed for solubilization as well as removal of pollutants. This study explores the impact of pH on the behavior of phenol in the micellar solution of CTAB via UV–Visible spectroscopy and surface tension measurements at room temperature. Binding coefficient (Kb), free energy change of binding (ΔGb), change in molar absorptivity (Δε), partition coefficient (Kc), free energy change of partitioning (ΔGp) and number of molecules per micelle (n) were determined at different pH. Results showed that phenol exhibits no appreciable interaction with the CTAB, however phenolate ions have the tendency to bind with CTAB micelles and penetrate in the palisade layer of CTAB.Surface properties such as surface excess (τmax), minimum area per molecule (Amin), packing parameter (P), surface area per head group (as), free energy changes of micellization (ΔGm), adsorption ΔGads, and transfer (ΔGtrans), and surface pressure (Π) for CTAB, and phenol in CTAB solutions were also determined. Interfacial studies supported the role of phenol in facilitating micellization of CTAB thermodynamically and hence a fall in CMC values of CTAB except for pH 7.11. Calculated interfacial parameters established the influence of phenol over rearrangement and surface adsorption of CTAB molecular ions at air/water interface. Surface tension results also showed that unionized phenol molecules have low surface activity (62.23mN/m), but when phenol is ionized into phenolate ion surface dramatically increased (44.17 mN/m).

Preparation of novel shell-ionotropically crosslinked micelles based on hexadecylamine and tripolyphosphate for cancer drug delivery

Aims Micellar systems have the advantage of being easily prepared, cheap, and readily loadable with bioactive molecular cargo. However, their fundamental pitfall is poor stability, particularly under dilution conditions. We propose to use simple quaternary ammonium surfactants, namely, hexadecylamine (HDA) and hexadecylpyridinium (HDAP), together with tripolyphosphate (TPP) anion, to generate ionotropically stabilized micelles capable of drug delivery into cancer cells. Methods optimized mixed HDA/HDAP micelles were prepared and stabilized with TPP. Curcumin was used as a loaded model drug. The prepared nanoparticles were characterized by dynamic light scattering, infrared spectroscopy, transmission electron microscopy, and differential scanning calorimetry. Moreover, their cellular uptake was assessed using flow cytometry and confocal fluorescence microscopy. Results The prepared nanoparticles were found to be stable under dilution and at high temperatures and to have a size range from 139 nm to 580 nm, depending on pH (4.6-7.4), dilution (up to 100 times), and temperature (25 – 80 °C). They were effective at delivering their load into cancer cells. Additionally, flow cytometry indicated the resulting stabilized micellar nanoparticles to be non-cytotoxic. Conclusions The described novel stabilized micelles are simple to prepare and viable for cancer delivery.

Modified cellulose nanocrystals enhanced polycaprolactone multifunctional films with barrier, UV-blocking and antimicrobial properties for food packaging

The packaging industry demands improved eco-friendly materials with new and enhanced properties. In this context, bio-nanocomposite films with antimicrobial and UV-shielding properties based on modified cellulose nanocrystals/polycaprolactone (MCNC/PCL) were fabricated via solution casting method, and then food packaging simulation was carried out. CNCs were obtained by acid hydrolysis followed by successful functionalization with Quaternary ammonium surfactant, confirmed by FTIR, XPS, XRD, TEM, and DLS analyses. Furthermore, the morphological, physical, antibacterial, and food packaging properties of all prepared films were investigated. Results showed that the mechanical, UV blocking, barrier properties, and antibacterial activity of all composite films were remarkably improved. Particularly, the addition of 3 wt% MCNC increased the tensile strength and elongation at break by 27.5 % and 20.0 %, respectively. Moreover, the permeability of O2, CO2, and water vapor dramatically reduced by 97.6 %, 96.7 %, and 49.8% compared to the Neat PCL. Further, the UV-blocking properties of the composite films were significantly improved. The antimicrobial properties of MCNC/PCL films showed good antimicrobial properties against S. aureus. Finally, cherry packaged with 1 and 3 wt% MCNC films exhibited satisfactory freshness after 22 days of preservation. Overall, the fabricated PCL nanocomposite films can be utilized in the food packaging industry.

Heparin-network-mediated long-lasting coatings on intravascular catheters for adaptive antithrombosis and antibacterial infection

Bacteria-associated infections and thrombosis, particularly catheter-related bloodstream infections and catheter-related thrombosis, are life-threatening complications. Herein, we utilize a concise assembly of heparin sodium with organosilicon quaternary ammonium surfactant to fabricate a multifunctional coating complex. In contrast to conventional one-time coatings, the complex attaches to medical devices with arbitrary shapes and compositions through a facile dipping process and further forms robust coatings to treat catheter-related bloodstream infections and thrombosis simultaneously. Through their robustness and adaptively dissociation, coatings not only exhibit good stability under extreme conditions but also significantly reduce thrombus adhesion by 60%, and shows broad-spectrum antibacterial activity ( > 97%) in vitro and in vivo. Furthermore, an ex vivo rabbit model verifies that the coated catheter has the potential to prevent catheter-related bacteremia during implantation. This substrate-independent and portable long-lasting multifunctional coating can be employed to meet the increasing clinical demands for combating catheter-related bloodstream infections and thrombosis.

Oil and Organic Liquids Incorporation into Fresh Geopolymer Pastes Using Suitable Quaternary Ammonium Surfactants.

The direct incorporation of low viscosity organic liquids (OL) such as dodecane and tributylphosphate (TBP) into fresh geopolymers (GP) is difficult and generally leads to variable amounts of un-incorporated OL remaining outside the hardened geopolymer. Experimentally, it is observed that a regular torque increase during OL incorporation corresponds to a suitable dispersion of the OL in the form of fine micrometric droplets. This can be obtained for TBP and dodecane by adding a small quantity of quaternary ammoniums salts (QAs) such as cetyltrimethylammonium bromide (CTAB). Shorter alkyl chains QAs, such as hexamethyltrimethylammonium (HMTA) can also be used but with a reduced efficiency. The positive impact of CTAB is then confirmed by the Washburn capillary rise method, showing that the interactions between TBP and CTAB-modified metakaolin are weaker compared to untreated powder. Finally, it is observed that the incorporation of TBP into geopolymer slurries is much easier than the incorporation of dodecane. The low interfacial tension measured between TBP and the activating solution (around 8 mN·m -1 ), contrasting with dodecane (29 mN·m -1 ), explains that the dispersion of TBP droplets in fresh metakaolin suspensions is more efficient.

Gemini Quaternary Ammonium Surfactants with Different Counterions-modified Montmorillonite for Efficient Removal of Methyl Orange.

Organic Na-montmorillonite (OMt-12-2-12·2Y - , Y=CH 3 CO 3 - , C 6 H 5 COO - and Br - ) modified by a series of Gemini quaternary ammonium surfactants with different counterions was prepared for enhancing the adsorption capacity of methyl orange. Compared with the initial adsorption capacity of 5.251 mg/g of Na-Mt, the adsorption effect of OMts under the optimal conditions increased by about 31~34 times. The adsorption isotherms and kinetics of all adsorption processes were respectively described by Langmuir and pseudo-second-order models. The structure, hydrophobicity and hydration of the counterions, as well as the affinity of the counterions with the long aliphatic chains, had a certain influence on the adsorption performance of OMts for methyl orange.

Evaluation of the Antitumor Activity of Quaternary Ammonium Surfactants.

Quaternary ammonium surfactants, due to their diverse chemical structure and their biological properties, can be used in medicine as DNA carriers, disinfectants, and antimicrobial and antitumor agents. In this study, using melanoma A375, colon adenocarcinoma HT-29 and normal human dermal fibroblast (NHDF) cells, we tested the hypothesis that the quaternary ammonium surfactants 2-dodecanoyloxyethyl)trimethylammonium bromide (DMM-11), 2-dodecanoyloxypropyl)trimethylammonium bromide (DMPM-11) and 2-pentadecanoyloxymethyl)trimethylammonium bromide (DMGM-14) act selectively against cancer cells. The results showed that these compounds led to the initiation of the apoptotic process of programmed cell death, as evidenced by the ratio of the relative expression of Bax protein to Bcl-2. The encapsulation of surfactants in liposomes allowed lower concentrations to be used. Moreover, encapsulation reduced their toxicity towards non-cancerous cells. The anticancer efficiency and apoptotic effect of the liposomal formulations with surfactants (DMM-11, DMPM-11 and DMGM-14) were higher than those of surfactant-free liposomes. Therefore, quaternary ammonium surfactant-loaded liposomes show significant potential as delivery vehicles for the treatment of melanoma and colon cancers. The use of nano-formulations offers the advantage of optimizing quaternary ammonium surfactant delivery for improved anticancer therapy.

N‐(4‐Chloromethylbenzyl)‐N, N‐dimethyldodecan‐1‐aminium Chloride: A Quaternary Ammonium Surfactant as Corrosion Inhibitor

AbstractThis study used a quaternary surfactant, N‐(4‐Chloromethylbenzyl)‐N, N‐dimethyldodecan‐1‐aminium chloride (CMBDAC), as an excellent corrosion inhibitor of C1018 carbon steel (C1018 CS) in harsh 15 % HCl acidizing condition. CMBDAC was synthesized with an excellent yield and characterized by NMR, FTIR, and TGA. Gravimetric weight loss (WL), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP) studies were employed to measure the efficacy of CMBDAC. At a relatively low concentration of 15 ppm, CMBDAC surpassed 90 % inhibition efficiency, with a maximum inhibition efficiency of 99.25 % being reached just for 50 ppm of CMBDAC. The inhibitor showed an efficacy of 96.16 % even at a temperature of 60 °C via the WL technique, showing potential to be used as a high‐temperature corrosion inhibitor. The adsorption isotherm study revealed that CMBDAC followed Langmuir adsorption isotherm. The Gibbs free energy of adsorption ( was calculated to be −40.43 kJ mol−1, indicating that CMBDAC was adsorbed via chemisorption. A very high value (1.68×105 L mol−1) of equilibrium constant ( ) suggested very strong adsorption of the inhibitor. PDP study disclosed that CMBDAC acted as a mixed‐type inhibitor. SEM‐EDX study demonstrated the adsorption of CMBDAC on the C1018 surface. Different DFT‐optimized parameters have been discussed in detail to support the superb inhibitory action indicated by CMBDAC.