Lifei Zhi

In this study, d-glucono delta-lactone was used as the raw material to sequentially conduct amidation, substitution, and quaternization reactions, through which a novel Gemini sugar-based amide organosilicon quaternary ammonium salt surfactant (2/3SiDDGMAPB) was designed and synthesized, and its molecular structures were confirmed by FT-IR and nuclear magnetic resonance. Notably, the results of physicochemical characterization and application performance investigation demonstrate that the surface tension of 2SiDDGMAPB is as low as 29.38 mN/m. Transmission electron microscopy, energy-dispersive spectroscopy, and dynamic light scattering characterizations reveal that 2SiDDGMAPB forms uniformly spherical micelles. The system exhibits robust foaming and foam-stabilizing performance across various water qualities and outstanding short-term foam stability in practical aqueous systems. Notably, both compounds display ultrahigh antibacterial activity against Staphylococcus aureus and Escherichia coli (with MIC as low as 0.001%), maintaining a 100% antibacterial rate even after 35 washing cycles. Toxicity tests in mice and skin irritation tests in rabbits confirm that 3SiDDGMAPB is practically nontoxic (LD50 > 5000 mg/kg) and nonirritating. 2/3SiDDGMAPB is a multifunctional surfactant combining rich foaming performance, long-acting bacteriostasis, and high biosafety, with excellent application potential and broad market prospects.

Using renewable D-gluconic acid δ-lactone as the starting material, two novel glucosamide-based organosilicon quaternary ammonium surfactants (2/3SiDDGPBH) were synthesized through an environmentally friendly three-step process involving amidation, hydrophobic modification, and quaternization. Comprehensive characterization demonstrated their exceptional performance: surface tension reduction to 33.4 mN/m (2SiDDGPBH) and 33.64 mN/m (3SiDDGPBH), uniform spherical micelles (1–10 nm and 30–100 nm) were formed, and outstanding foam properties with 3SiDDGPBH developed, showing superior foamability and stability. Material modification tests on polymethyl methacrylate (PMMA) plates, mature acacia leaves, oilpaper, vegetable-tanned top-grain leather, and melamine-formaldehyde resin (MFR) faced with plywood revealed excellent spreading performance and durability, particularly for 3SiDDGPBH-treated MFR plywood, which maintained excellent spreading performance even after 80 washing cycles. Scanning electron microscopy (SEM) analysis confirmed that the Si wt% of MFR plywood treated with 2/3SiDDGPBH and scrubbed MFR plywood both exhibited a significant increase, and the 3SiDDGPBH-treated MFR plywood demonstrated superior bonding properties. These surfactants combine low surface tension, excellent foaming properties, and outstanding spreading performance, demonstrating broad application prospects in fields such as pesticide adjuvants, industrial and household cleaning agents, cosmetics, oilfield extraction, textile printing and dyeing, and functional coatings.

Amidation of lactobionic acid with N,N-dimethylaminopropyltriamine was conducted to obtain N-(3′-dimethylaminopropyl)-lactamido-3-aminopropane (DDLPD), which was quaternized with bromoalkanes of different carbon chain lengths to synthesize double-stranded lactosylamide quaternary ammonium salt N-[N′[3-(lactosylamide)]propyl-N′-alkyl] propyl-N,N-dimethyl-N-alkylammonium bromide (C_nDDLPB, n = 8, 10, 12, 14, 16). The surface activity and the adsorption and aggregation behaviors of the surfactants were investigated via equilibrium surface tension, dynamic light scattering, and cryo-electron microscopy measurements in an aqueous solution. The application properties of the products in terms of wettability, emulsification, foam properties, antistatic, salt resistance, and bacteriostatic properties were tested. C_nDDLPB exhibited a low equilibrium surface tension of 27.82 mN/m. With an increase in the carbon chain length, the critical micellar concentration of C_nDDLPBD decreased. Cryo-electron microscopy revealed that all products except C₈DDLPB formed stable monolayer, multi-layer, and multi-compartmental vesicle structures in an aqueous solution. C₁₄DDLPB has the best emulsification performance on soybean oil, with a time of 16.6 min; C₁₄DDLPB has good wetting and spreading properties on polytetrafluoroethylene (PTFE) when the length of carbon chain is from 8 to 14, and the contact angle can be lowered to 33°~40°; C_nDDLPB has low foam, which is typical of low-foaming products; C₈DDLPB and C₁₀DDLPB both show good antistatic properties. C₈DDLPB and C₁₄DDLPB have good salt resistance, and C₁₂DDLPB has the best antimicrobial property, with the inhibition rate of 99.29% and 95.28% for E. coli and Gluconococcus aureus, respectively, at a concentration of 350 ppm.

A series of double-chain quaternary ammonium salt surfactants N-[N′[3-(gluconamide)] propyl-N′-alkyl]propyl-N,N-dimethyl-N-alkyl ammonium bromide (C_nDDGPB, where n represents a hydrocarbon chain length of 8, 10, 12, 14 and 16) were successfully synthesized from D (+)-glucose δ-lactone, N,N-dimethyldipropylenetriamine, and bromoalkane using a two-step method consisting of a proamine-ester reaction and postquaternization. Their surface activity, adsorption, and aggregation behavior in aqueous solution were investigated via measurements of dynamic/static surface tension, contact angle, dynamic light scattering, and transmission electron microscopy. An analysis of their application performance in terms of wettability, emulsifying properties, toxicity, and antibacterial properties was conducted. The results show that with increasing the carbon chain length of the C_nDDGPB surfactants, their critical micelle concentration (CMC) increased and the pC₂₀ and efficiency in the interface adsorption of the target product gradually decreased. Moreover, the influence of the hydrophobic carbon chain length on the surface of polytetrafluoroethylene (PTFE) was even greater for the wetting effect, reducing the contact angle to 32° within the length range of C8–C14. The results of the contact angle change and the wettability experiments proved that C₁₀DDGPB exhibited the best wettability. The liquid paraffin and soybean oil emulsification ability of C_nDDGPB showed an upward trend followed by a downward trend with the growth of the carbon chain, with C₁₂DDGPB exhibiting the best emulsification performance. The D_long/D_short ratio was far lower than 1, which indicates mixed-kinetic adsorption. The surfactants formed spherical micelles and showed a unique aggregation behavior in aqueous solution, which showed an increase–decrease–increase trend with the change in concentration. A cell toxicity and acute oral toxicity experiment showed that the C_nDDGPB surfactants were less toxic than the commonly used surfactant dodecyldimethylbenzyl ammonium chloride (1227). In addition, at a concentration of 150 ppm, C_nDDGPB exhibited the same bacteriostatic effect as 1227 at a concentration of 100 ppm. The results demonstrate that sugar-based amide cationic surfactants are promising as environmentally friendly disinfection products.

A novel tetrasiloxane-tailed surfactant bearing oligo(ethylene oxide) methyl ether and sugar moieties (TGA-2) has been evaluated. The dynamic surface tension (DST) and spreading properties imparted to water by TGA-2 have been investigated. DST parameters, namely effective diffusion coefficient, activation barrier, and contact angle have been calculated and analyzed. A general diffusion mechanism of surfactant TGA-2 has been delineated. DST analyses yielded significantly different long-term (D_L) and short-term (D_S) diffusion coefficients, implying that the adsorption process involves a mixed diffusion-kinetic mechanism. Adsorption activation energies (E_a) of the surfactant TGA-2 have been measured as 9.14 kJ/mol at 4 × 10⁻⁵ M and 19.37 kJ/mol at 4 × 10⁻⁴ M. These small E_a values suggest that the tetrasiloxane group is favorable for adsorption. A polytetrafluoroethylene (PTFE) membrane was chosen as a solid substrate to demonstrate the spreading ability imparted by TGA-2. At a TGA-2 concentration of 0.5% in water, the contact angle decreased from 57° to 7.8° in 60 s, such that the droplets became almost flat. GRAPHICAL ABSTRACT

The stability of anionic‐cationic surfactant solutions and the antimicrobial properties of novel N,N‐dimethyl‐N‐[3‐(gluconamide/lactobionamide)]propyl‐N‐alkylammonium bromides (CnDGPB and CnDLPB), N‐methyl‐N‐hydroxyethyl group‐N‐[3‐(gluconamide)‐propyl]‐N‐alkylammonium bromide (CnMHGPB) and star‐shaped gluconamide‐type cationic surfactants N‐dodecyl‐N,N‐bis[(3‐d‐gluconylamido)propyl]‐N‐alkylammonium bromide (CnDBGB) were investigated. Mixed stability in combination with sodium n‐alkylbenzenesulfonate (LAS) was determined via transmittance; stability is achieved when percent transmittance was greater than 90 %. Transmittance results suggest that these cationic surfactants can form stable solutions with anionic surfactants over a broad concentration range. The inhibition activity of C_nDBGB is the best among the three kinds of glucocationic surfactants. Antimicrobial activity of C₁₂ surfactants was the best, C₁₄ was the second and C₁₀ was the worst. Moreover, antibacterial activity of glucose‐based cationic surfactants was greater than lactose‐based cationic surfactants.