ABSTRACT The interactions of naphthyl boronic acid (NBA) with cationic, anionic, and nonionic surfactants, as well as trimethoxymethylsilane (TMS), were investigated in both the ground and excited electronic states. Silver/NBA/surfactant nanomaterials were prepared, and their optical properties were examined using UV–visible absorption and fluorescence spectroscopy. The critical micelle concentration (CMC), binding constants, and Gibbs free energy changes (ΔG) associated with NBA–surfactant complex formation were evaluated to understand the micellization process. As the surfactant concentration increased, the absorption spectra of NBA exhibited a gradual decrease in absorbance with little or no change in the absorption maximum. In contrast, the fluorescence spectra showed noticeable variations in both the emission wavelength and fluorescence intensity, indicating changes in the local microenvironment surrounding the NBA molecules. Progressive changes in both absorption and emission characteristics confirmed the interaction of NBA with the surfactant aggregates. The negative Gibbs free energy values demonstrate that the association between NBA and the surfactants occurs spontaneously and is thermodynamically favorable under the experimental conditions. In the ground state, NBA displayed the strongest binding affinity toward sodium lauryl sulfate (SLS), whereas cetylpyridinium chloride (CPC) exhibited the highest affinity in the excited state. Furthermore, incorporation of NBA, individual surfactants, and NBA–surfactant assemblies into silver nanoparticles resulted in distinct red and blue shifts in both the absorption and fluorescence maxima, reflecting changes in the electronic environment arising from nanoparticle–surfactant interactions.
Fluorine-free foams stabilized by nanoparticles have excellent fire-extinguishing performance and are expected to become a substitute for traditional aqueous film forming foam (AFFF). However, there are still many problems in the performance of NP-stabilized fluorine-free foams that need to be studied. This investigation centers on the rheological behavior of fluoride-free foams stabilized by nano-hydroxide aluminum. Measurements of electrical conductivity, viscosity, and surface tension were conducted on the mixed dispersions, and the resulting data were used to evaluate the role of nanoparticles in modifying foam stability. Through model fitting, the rheological properties of the mixed dispersion and foam were studied in depth. It was observed that the viscosity and stability of the mixed dispersion were elevated in the presence of nanoparticles, with this promoting effect becoming more pronounced at higher nanoparticle loadings. The foams stabilized by nanoparticles have good resistance to external shear and thixotropic recovery ability, and the shear stress change of the foam is consistent with the Cross model. With the increasing nanoparticle concentration, the linear viscoelastic region (LVR) of the foam widens, the flow point is delayed, and the viscoelasticity increases. The creep deformation resistance of the foam also increases, and the stability of the internal structure is significantly improved. The findings of this work offer valuable guidance for formulating fluorine-free firefighting foam agents.
In pesticide suspension concentrate formulations, interfacial adsorption of dispersants onto active-ingredient particles and solubilization of pesticide molecules by dispersant micelles frequently coexist; however, analytical methods capable of simultaneously characterizing these interfacial and bulk-phase processes remain limited. Herein, a multivariate calibration strategy combining ultraviolet-visible (UV-Vis) spectrophotometry with partial least squares (PLS) regression and competitive adaptive reweighted sampling (CARS) was developed. The method enabled simultaneous determination of residual tristyrylphenol ethoxylates (TSPEO) and prometryn in processed supernatants, allowing TSPEO adsorption to be quantified indirectly by mass balance. In the hold-out validation set, the CARS model incorporating single-component (SC) spectra achieved coefficients of determination for validation (R 2 val) of 0.9965 and 0.9904 and root mean square errors of prediction (RMSEP) of 6.1471 and 1.0129 mg/L for TSPEO and prometryn, respectively. Prometryn predictions also showed good agreement with high-performance liquid chromatography (HPLC) measurements. Application of the method showed that wet milling increased the Langmuir-derived apparent maximum adsorption capacity of TSPEO from 4.02 to 13.18 mg/g, whereas the nonmilled system exhibited linear micellar solubilization of prometryn above the critical micelle concentration (CMC), with a weight solubilization ratio (WSR) of 0.0291 g/g. These results provide a quantitative framework for investigating coupled dispersant adsorption and pesticide solubilization in suspension concentrate systems.
ABSTRACT Modified polydimethylsiloxanes (PDMS) are key components in silicone‐based defoamers that play a crucial role in regulating interfacial tension. In this work, a series of modified PDMS were synthesized using polyethylene glycol (PEG) as the hydrophilic chain, and the hydrophobic graft chains were designed with different structures of 1‐dodecene, styrene, and allyloxy dodecylphenol. Surface tension measurements revealed that simply increasing the proportion of hydrophobic dodecene chains could only slightly lower the surface tension of the modified PDMS. In contrast, using equimolar allyloxy dodecylphenol as hydrophobic chains to replace dodecene can significantly reduce the surface tension of the modified PDMS from 21.45 mN/m (for the dodecene‐grafted PDMS) to 21.03 mN/m. After formulating these modified PDMSs into defoamers, the samples grafted with allyloxy dodecylphenol, compared with the common dodecene grafted ones, significantly reduced foam elimination time upon compounding and extended foam inhibition time. In addition, it was also observed that proper hydrophobicity (HLB = 5.34) enables rapid foam rupture, while relatively higher HLB can sustain long‐term anti‐foaming activity.
ABSTRACT A tricationic surfactant containing pyridinium and quaternary ammonium centers, denoted mono16‐diN + ‐PyN + , was synthesized and evaluated as a corrosion inhibitor for carbon steel in 1.0 M HCl. Its structure was confirmed by FT‐IR and 1 H NMR spectroscopy, while its inhibition performance was investigated by gravimetric, electrochemical, contact‐angle, adsorption, surface, and density functional theory analyses. Gravimetric measurements showed inhibition efficiencies of 98.80%–99.48% over the investigated immersion periods, even at very low inhibitor concentrations. Electrochemical impedance spectroscopy revealed an increase in charge–transfer resistance from 165.5 Ω for the blank solution to 1238 Ω at 10 ppm, accompanied by a marked decrease in double‐layer capacitance, indicating formation of a protective adsorbed layer. Potentiodynamic polarization confirmed mixed‐type inhibition: at 10 ppm, the corrosion current density decreased from 492 to 37.4 μA cm −2 and the corrosion rate from 5.71 to 0.43 mm year −1 , corresponding to an inhibition efficiency of 92.4%. The water contact angle increased from 17.15° to 71.50°, demonstrating enhanced surface hydrophobicity after adsorption. The adsorption behavior was best described by the Langmuir isotherm, and negative Δ G ° ads values indicated spontaneous adsorption involving electrostatic and charge–transfer interactions. SEM, EDS, and Gwyddion‐derived 3D surface profiles showed reduced surface damage and fewer corrosion products in the presence of the inhibitor. DFT results further indicated that the heteroatom‐rich head group, pyridinium unit, cationic centers, and hydrophobic alkyl chain contribute synergistically to adsorption and barrier formation. These findings demonstrate that mono16‐diN + ‐PyN + provides highly effective corrosion protection at low concentrations.
