• Journal of Microbiology and Biotechnology
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• v.29 no.8
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• pp.1240-1247
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• 2019

This study was conducted to examine the inactivation effect of the combined treatment of high hydrostatic pressure (HHP; 400 MPa for 1, 3, and 5 min) and cationic surfactant washing (0.05% benzethonium chloride, BEC) against Listeria monocytogenes inoculated on fresh-cut broccoli (FCB). Washing with BEC at concentrations exceeding 0.05% resulted in 2.3 log-reduction of L. monocytogenes counts on FCB, whereas HHP treatment had approximately 5.5-5.6 log-reductions regardless of the treatment time. Scanning electron microscopy corroborated microbial enumeration, revealing that the combined treatment was more effective in removing L. monocytogenes from FCB than individual treatment with HHP or BEC. Color and total glucosinolate content were maintained after the combined treatment, although the hardness of the FCB slightly decreased. The results clearly suggest that the combined treatment of HHP and BEC washing has potential value as a new sanitization method to improve the microbial safety of FCB.

• Macromolecular Research
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• v.15 no.6
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• pp.498-505
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• 2007

This study demonstrated the in-situ functionalization with polymers of multi-walled carbon nanotubes (MWNTs) via emulsion polymerization. Polystyrene-functionalized MWNTs were prepared in an aqueous solution containing styrene monomer, non-ionic surfactant and a cationic coupling agent ([2-(methacryloyloxy)ethyl]trime-thylammonium chloride (MATMAC)). This process produced an interesting morphology in which the MWNTs, consisting of bead-string shapes or MWNTs embedded in the beads, when polymer beads were sufficiently large, produced nanohybrid material. This morphology was attributed to the interaction between the cationic coupling agent and the nanotube surface which induced polymerization within the hemimicellar or hemicylindrical structures of surfactant micelles on the surface of the nanotubes. In a solution containing MATMAC alone without surfactant, carbon nanotubes (CNTs) were not well-dispersed, and in a solution containing only surfactant without MATMAC, polymeric beads were synthesized in isolation from CNTs and continued to exist separately. The incorporation of MATMAC and surfactant together enabled large amounts of CNTs (> 0.05 wt%) to be well-dispersed in water and very effectively encapsulated by polymer chains. This method could be applied to other well-dispersed CNT solutions containing amphiphilic molecules, regardless of the type (i.e., anionic, cationic or nonionic). In this way, the solubility and dispersion of nanotubes could be increased in a solvent or polymer matrix. By enhancing the interfacial adhesion, this method might also contribute to the improved dispersion of nanotubes in a polymer matrix and thus the creation of superior polymer nanocomposites.

• Journal of the Korean Applied Science and Technology
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• v.31 no.1
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• pp.7-13
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• 2014

A cationic ester type surfactant, namely N-2-hydroxy-3-(2-hydroxyacetoxy) proply-N,N-dimethyldodecylaminium chloride(HPDA) was synthesized and confirmed by FT-IR and $^1H$-NMR spectroscopy. Surface tensions on the diluted aqueous solutions of the synthetic compounds were measured and evaluated critical micelle concentration. Surface tension was 33~34 dyne/cm in the range of $10^{-3}{\sim}10^{-2}mol/L$ and critical micelle concentration(c.m.c) value was $8.5{\times}10^{-3}mol/L$ by surface tension method. Emulsifying properties of the synthetic surfactant(HPDA) and Sodium lauryl sulfate (SLS), tetradecyl trimethyl ammonium bromide (TTAB) was tested. As a results, synthetic glycolic acid ester type compounds(HPDA) has been confirmed as a good emulsifier. The foaming power and stability of synthesized ester type surfactant was measured by Ross-Miles method.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.38-45
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• 2009

In this study, interfacial properties were measured for imidazoline type cationic surfactant system which has been widely used as a fabric softener, a dispersant, an anti-static agent, a bleach activator, and an emulsifier. The CMC of imidazoline surfactant was near $6{\times}10^{-5}mol/L$ and the surface tension at CMC was about 32 mN/m. It was found that surface tension was not affected by surfactant concentration but decreased with an increase in pH. The interfacial tension between 1 wt% aqueous solution and n-dodecane was shown to be about 0.01 mN/m and equilibration time was not affected by pH. Phase behavior experiment in a binary aqueous surfactant system showed that only micellar solution of $L_1$ phase was found under conditions of temperature and pH investigated during this study. Only a two-phase region consisting of lower-phase microemulsion in equilibrium with excess oil phase existed under the same conditions, when oil was added to the binary surfactant system. The foam stability measured with 1 wt% surfactant solution increased with pH, which is consistent with surface tension measurement result. QCM(quartz crystal microbalance) measurement showed that surfactant adsorption increased with surfactant concentration but decreased with pH. According to the friction measurement, best fabric softening effect by imidazoline surfactant system was found under alkali conditions.

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.1096-1098
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• 1999

MCM-41 type spherical mesoporous silica material was synthesized, under basic conditions, in the presence of cationic surfactant as templating species. The cationic surfactants used in this experiment were octyltrimethylammonium bromide, dodecyltrimetylammonium bromide, cetyltrimethylammonium bromide, octadecyltrimethyammonium bromide and cetylpyridium bromide. Specific surface area of spherical MCM-41 was as high as $1500m^2/g$ and the pore size decreased with increasing alkyl chain length of surfactant.

• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.5
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• pp.711-717
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• 1996

This study was carried to figure out the effect of washing on the cationic surfactant (DSDMAC) absorption by nylon fabrics washed with anionic surfactant(SDBS). Cationic surfactant absorption, static electricity, and fabric stiffness of washed and unwashed nylon fabrics were estimated. And to check the correlation between DSDMAC absorption and SDBS absorption, SDBS absorption by nylon fabrics were measured The results were as follows; 1. Nylon fabrics washed with SDBS absorbed more DSDMAC than unwashed fabrics. The more SDBS absorbed by nylon fabrics, the more DSDMAC absorbed. This is account for the increase in negative zeta potential of washed nylon fabrics. 2. Absorption of SDBS by nylon fabrics increased static electricity. Absorption of DSBMAC by washed and unwashed nylon fabrics greatyl decreased static electricity, and static electricity of washed nylon fabrics more decreased than that of unwashed nylon fabrics. 3. When washing cycles were under 20, DSDMAC absorption decreased fabric stiffness. As washing cycles were over 20, DSDMAC deposited as particles acted as points of weak adhesion between adjacent fibers, so increased the fabric stiffness.

• Bulletin of the Korean Chemical Society
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• v.7 no.2
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• pp.113-116
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• 1986

Spectral behaviors of cationic dyes, methylene blue(MB) and acridine orange(AO), with varying concentrations of sodium dodecylsulfate(SDS) were studied. At low concentration of SDS(<1mM), these dyes formed insoluble dye-surfactant aggregates. When [SDS] is 4-5 mM, the aggregates were dissolved into mixed micelles of constant composition. At higher concentration of [SDS], the composition of mixed micelles were changed with [SDS], resulting only monomeric form of dyes in micelles. AO-SDS system showed greater aggregating and less dissolving properties, and weaker effect of salt than MB-SDS system did. These were attributed to the greater hydrophobic nature of the former dye. The monomer/dimer ratios of dyes in mixed micelles at given [SDS] were greatest at $20^{\circ}C$, reflecting the dependency of CMC of the surfactant on temperature.

• Journal of Electrochemical Science and Technology
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• v.12 no.3
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• pp.308-316
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• 2021

In this work, we report synthesis, characterization and corrosion inhibition properties of cationic thiol surfactant-capped silver (SC-Ag-NPs) and gold (SC-Au-NPs) nanoparticles. SC-Ag-NPs and SC-Au-NPs were characterized using regular techniques include TEM. Corrosion study was carried out using carbon steel (CS) in 3.5% NaCl aqueous solution and characterized using multiple electrochemical techniques. Our results suggest that the paint containing SC-Ag-NPs and SC-Au-NPs endow efficient corrosion protection to the CS. Especially, SC-Au-NPs based paint form a stronger barrier between the metal and the corrosive ions, leading to better inhibition properties.

• Applied Chemistry for Engineering
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• v.31 no.4
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• pp.429-437
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• 2020

In this study, a cationic gemini surfactant was synthesized using isosorbide, in order to modify the alkyl chain length in the range of C₁₀~C₁₆. The c.m.c and surface tension of the synthesized cationic gemini surfactant were measured to be in the ranges of 5.13 × 10^-4~1.62 × 10^-4 mol/L and 31.86~37.41 dyne/cm, respectively. The surface tension increased with increasing the length of the alkyl group. In addition, as the area per molecule occupied by the surfactant adsorbed on the interface increased with the reduced extent of adsorption, the bubble generation at the air-water interface decreased. The emulsifying capacity in benzene was maintained above 60 ± 5% after 8 h while that in soybean oil tended to decrease above 50 ± 5%. The performance was superior in benzene, a highly hydrophobic substance, and the emulsion stability was shown to be consistent beyond 1 h during the preparation of pre-emulsion in oil and water. The antimicrobial activity was dependent on the length of the hydrophobic chain of the synthesized cationic gemini surfactant due to the increased size of the clean zone in Escherichia coli (E.coli) and Staphylococcus aureus.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.3
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• pp.10-18
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• 1999

The influence of simple electrolyte or anionic trashes on cationic starch adsorption was examined using deinked pulp and bleached thermomechniical pulp. Adsorbed amounts of cationic starches increased slightly , then decreased abruptly as the concentration of simple electrolyte increased. This phenomenon was discussed based on the compression of electrical double layer and conformation change of starch molecules. Also, the effect of the type of simple electrolytes on starch adsorption was examined and discussed. Addition of sodium slilicate increased starch adsorption since it increased surface charge density of fibers. On the other hand, addition of kraft lignin decreased cationic demand of the pulp slurries and adsorbed amounts of cationic starches. Nonionic surfactant did not show any significant effect on the cationic demand of pulp slurries. When simple electrolytes were added to the stock , grater adsorption or cationic starches was obtained with starches of lower degree of substitution . On t도 other hand, amount of adsorbed starches decreased for lower DS starches when the concentration of anionic trashes increased.