Surface Properties Of Surfactants Research Articles

Micellization Properties, Molal Volume and Polarizability of Newly Synthesized Gemini-Cationic Surfactants

In the present study, three Gemini cationic surfactants were prepared and characterized: N, Nʹ-((1,4-phenylenebis(oxy)) bis (2-oxoethane-2,1-diyl)) bis (N, N-dimethyl-3-octanamidopropan-1-aminium) (C1), N, Nʹ-((1,4-phenylenebis(oxy)) bis (2-oxoethane-2,1-diyl)) bis (3-dodecaneamido-N, N-dimethylpropan-1-aminium) (C2), N, Nʹ-((1,4-phenylenebis(oxy)) bis (2-oxoethane-2,1-diyl)) bis (N, N-dimethyl-3-palmitamidopropan-1-aminiccum) (C3). In water solutions, the CMC value of the prepared surfactants was detected by conductivity, surface tension, refractive index, molal volume, and spectrophotometric measurements. The effect of mixing of Gemini surfactant on CMC value was studied and discussed. Some surface properties of surfactants like excess surface concentration and minimum area per molecule were also calculated and discussed. Solvation thermodynamic parameters such as association constant, molal volume, and polarizability were also determined and discussed. The CMC value decreased from C1 to C3 due to an increase in the carbon chain length. Different physical methods show good agreement between CMC values detected by several techniques effect of mixing surfactants on CMC was also studied For example detecting CMC value for C1 when C2 and C3 are added at two concentrations, before and after the CMC values of the added surfactants, (0.00001M, 0.0003M) in water solution. and so on.

The influence of a high-frequency electromagnetic field on the adsorption ability of ionogenic surface-active substances

The influence of a high-frequency electromagnetic field on the adsorption characteristics of micelle-forming surface-active compounds (surfactants) at the solution-air boundary was studied. It was shown that not only the volume but also surface properties of surfactants could change under the action of a high-frequency electromagnetic field on their solutions.

Effect of Oxypropylene Chain Length on the Surface Properties of Dialkyl Glycerol Ether Nonionic Surfactants

In this work, as a continuation of our studies concerning the preparation and surface properties of nonionic surfactants, derivatives of 1,3-dialkoxy-2-propanols and 1,3-dialkoxy(oligooxypropylene)-2-propanols with oligooxypropylene chains have been synthesized and investigated. The surface activity of these compounds has been determined, i.e., critical micelle concentration (CMC), surface excess concentration (Γ), surface area demand per molecule (A), surface tension at CMC (γCMC), ΔGads°, and ΔGmic°. A linear decrease of the log CMC vs number of oxypropylene groups is observed, and based on the Shinoda equation the work of cohesion per oxypropylene group when passing from molecular to micellar state is calculated for 0.43 kT. The equivalent of CH2 in the aliphatic alcohol group is ca. 2.50 oxypropylene units. Surface properties of these surfactants, i.e., cloud point, wetting ability, contact angle, foam height, and emulsion stability type (O/W), have been determined as well.

Effect of Hard River Water on the Surface Properties of Surfactants

The surface properties [effectiveness of surface tension reduction (γ CMC ), critical micelle concentration (CMC), efficiency of surface tension reduction (pC 20 ), maximum surface excess concentration (Γ max ), minimum area/molecule at the interface (A min ), and the (CMC/C 20 ) ratio] of well-purified anionic, nonionic, and cationic surfactants, some of which are widely used in daily chemical and industrial products, were investigated at 25 °C in hard river water. The studied surfactants show somewhat greater surface activity in hard river water than in distilled water, but in particular, for anionic surfactants a marked effect of hard river water on surface active properties was observed. The effect of hard river water on surface active properties is, in decreasing order, anionics > cationics > nonionics. For alkyl poly(oxyethylene) glycols, the effect on surface properties is interpreted in terms of complex formation between the ether oxygen atoms of the poly(oxyethylene) group and divalent hardness ions. The linear relationship between the pC 20 or CMC values and the number of carbon atoms in the alkyl chain observed in distilled water was confirmed in hard river water. For alkyl poly(oxyethylene) sulfates, the slope of the plot indicates an effect of the alkyl chain on adsorption at the air/water interface or on micellization similar to that observed for nonionic surfactants in distilled water.