Relationship Between Critical Micelle Concentrations and Minimum Inhibitory Concentrations for Some Non-Aromatic Quaternary Ammonium Salts and Amine Oxides

Devı́nsky, Ferdinand; Lacko, I.; Mlynarcík, D; Račanský, V.; Krasnec, Ľ.

doi:10.1515/tsd-1985-220105

Cited by 92 publications

(15 citation statements)

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“…The purity of the compounds was assessed from surface tension measurements and comparison with known values of the critical micelle concentrations. The results are in good agreement with measurements by others. ,− No minima were observed in the surface tension versus ln c plots.…”

Section: Experimental Methodssupporting

confidence: 91%

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Neutron Reflectometry of Quaternary Gemini Surfactants as a Function of Alkyl Chain Length: Anomalies Arising from Ion Association and Premicellar Aggregation

Li¹,

Dong²,

Thomas³

et al. 2011

Langmuir

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We have measured the structure and properties of a series of dicationic quaternary ammonium compounds α,ω-bis(N-alkyl dimethyl ammonium)hexane halides (Cn-C6-Cn) for values of the alkyl chain length n of 8, 9, 10, 11, 12, and 16, and a series of α,ω-bis(N-alkyl dimethyl ammonium)diethylether halides (Cn-C2OC2-Cn) for values of n of 8, 12, and 16, as well as C8-C12-C8 and C12-C10-C12 at the air/water interface. Although the critical micelle concentration (CMC) in the two series decreases in the normal way, that is, logarithmically, with increasing chain length, the limiting surface tension at the CMC and the limiting area per molecule both increase with chain length, in the opposite direction from comparable single chain surfactants. The structures of the surface layers, which were determined by neutron reflectometry, indicate that the anomalous behavior of the surface tension and area are probably caused by poor packing of the gemini side chains between adjacent molecules. Comparison of the directly determined surface coverage using neutron reflectometry and the apparent coverage determined by application of the Gibbs equation to surface tension data gives an experimental measurement of the prefactor in the Gibbs equation, which should be 3 for these geminis. It was found to vary from about 3 for the two C16 geminis down to about 1.5 for the two C8 geminis. We have devised a simple quantitative model that explains this variation and earlier observations that the Gibbs prefactor for C12-Cn-C12 (n varying from 3 to 12) is around 2. The model is consistent with the conductivity, NMR, and fluorescence measurements of other authors. This model shows that both dimerization and ion association are required to explain the surface tension behavior of cationic gemini bromide surfactants and that, in many cases, the prefactor itself varies with concentration.

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Section: Experimental Methodssupporting

confidence: 91%

“…The results are in good agreement with measurements by others. 1,[8][9][10][11] No minima were observed in the surface tension versus ln c plots.…”

Section: ' Experimental Methodsmentioning

confidence: 99%

Neutron Reflectometry of Quaternary Gemini Surfactants as a Function of Alkyl Chain Length: Anomalies Arising from Ion Association and Premicellar Aggregation

Li¹,

Dong²,

Thomas³

et al. 2011

Langmuir

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“…Cationic surfactants generally show antimicrobial activity. Devinsky and co-workers sought to determine quantitative structure/activity relationships between the antimicrobial activities and micellar properties of variously modified quaternary ammonium surfactants. − With a decrease in cmc, both the germicidal activity and protein-binding ability of quaternary ammonium salts increased. , Compounds with a cmc value of 1 × 10 -2 to 1 × 10 -4 M were active, regardless of whether the surfactant was monomeric or polymeric.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Surface and Antimicrobial Properties of Novel Cationic Surfactants

et al. 2000

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A series of surfactants with tuned polarity were prepared, including a new class of compounds: gluco-pyridinium surfactants. Pure anomers were obtained by chromatographic separation. The conductivity and surface tension of surfactant solutions in water were measured, and provided interesting information regarding their aggregation behavior. Peculiarities were observed in the premicellar range. Tensidic parameters correlated with antimicrobial activity. A few parameters, mainly the hydrophobicity of the headgroup, may play a role in finding more efficient antimicrobial structures.

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“…Bis(quaternary ammonium halide) geminis were first synthesized and studied for their superior performance, relative to monoquaternary ammonium halides, as catalysts in organic reactions. 5 Later, they came to be studied for their bactericidal capabilities 6 and for their unusual physicochemical properties. Although this class of cationic surfactants has been studied for over two decades, 7 the details of its structure-performance relationship remain elusive.…”

Section: Introductionmentioning

confidence: 99%

Aberrant Aggregation Behavior in Cationic Gemini Surfactants Investigated by Surface Tension, Interfacial Tension, and Fluorescence Methods

1999

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Bis(quaternary ammonium halide) surfactants (gemini surfactants) having, variously, diethyl ether, monohydroxypropyl, and dihydroxybutyl spacer groups have been investigated by surface tension, interfacial tension, and steady-state fluorescence techniques. The critical micelle concentration (cmc) and area per molecule (A min) are shown to deviate from the expected patterns of behavior as the number of carbon atoms in the alkyl chain (n) increases beyond a certain maximum. This aberrant behavior is observed at the hydrocarbon/water as well as the aqueous/air interface. The unexpected values of the physicochemical parameters at long alkyl chain length have been interpreted on the basis of a concentration region in which submicellar or multilayer structures are forming. Fluorescence measurements provide confirmation of cmc values by an alternative technique. Comparison of the fluorescence emission maxima profiles of the gemini surfactants with those of their monoquaternary analogues demonstrates that there is a continuously changing shape with change in n for the geminis, whereas the profiles for nongeminis are invariant. Long-chain geminis exhibit a gradually sloping sigmoidal profile, indicating a variety of environments experienced by pyrene-3-carboxaldehyde between the totally aqueous environment at low surfactant concentration and the hydrophobic (entirely micellar) environment at high surfactant concentration. The large variation in the polarity of the probe environment between these two extremes may be attributed to the formation of submicellar structures.

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Relationship Between Critical Micelle Concentrations and Minimum Inhibitory Concentrations for Some Non-Aromatic Quaternary Ammonium Salts and Amine Oxides

Cited by 92 publications

References 0 publications

Neutron Reflectometry of Quaternary Gemini Surfactants as a Function of Alkyl Chain Length: Anomalies Arising from Ion Association and Premicellar Aggregation

Neutron Reflectometry of Quaternary Gemini Surfactants as a Function of Alkyl Chain Length: Anomalies Arising from Ion Association and Premicellar Aggregation

Synthesis and Surface and Antimicrobial Properties of Novel Cationic Surfactants

Aberrant Aggregation Behavior in Cationic Gemini Surfactants Investigated by Surface Tension, Interfacial Tension, and Fluorescence Methods

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