Surfactants physicochemical properties

Nakagawa, T., K. Shinoda, Physicochemical studies in aqueous solutions of nonionic surface active agents, in K. Shinoda, T. Nakagawa, B. Tamamushi, T. Isemura, eds.. Colloidal Surfactants Physicochemical Properties, Academic Press, New York, 1963. 

Berthod, A. Tomer, S. and Dorsey, J. G. (2001). Polyoxyethylene alkyl ether nonionic surfactants physicochemical properties and use for cholesterol determination in food. Talanta, 55,1, 69-83. 

TABLE 11 Survey of Physicochemical Properties of Alkyl Ether Carboxylates Compared to Other Surfactants... 

In summary, therefore, AOS (as far as has been determined) does not represent any significant health hazard. The most notable biological response is that of skin/eye irritation, which may be expected as a result of the physicochemical properties of a surfactant. 

Protein-Based Surfactants Synthesis, Physicochemical Properties, and Applications, edited by Ifendu A. Nnanna and JidingXia... 

It was mentioned previously that the narrow range of concentrations in which sudden changes are produced in the physicochemical properties in solutions of surfactants is known as critical micelle concentration. To determine the value of this parameter the change in one of these properties can be used so normally electrical conductivity, surface tension, or refraction index can be measured. Numerous cmc values have been published, most of them for surfactants that contain hydrocarbon chains of between 10 and 16 carbon atoms [1, 3, 7], The value of the cmc depends on several factors such as the length of the surfactant chain, the presence of electrolytes, temperature, and pressure [7, 14], Some of these values of cmc are shown in Table 2. 

Since that time an enormous number of surfactants covering a wide range of chemical and physicochemical properties have been developed for quite universal as well as specific tasks in domestic and industrial applications. The criteria for selection of a surfactant for industrial production is directly connected with the feasibility of large-scale production. This is determined by several factors including availability and costs of raw materials, cost of manufacture, and performance of the finished products. In addition to these aspects, environmental considerations likewise play an increasingly important role. 

The fate of surfactants (Fig. 1.17) in wastewater treatment plants (WWTP) is determined by, among other factors, the composition of the wastewater, the operational type of the WWTP and the physicochemical properties of the surfactant molecule itself. In general, WWTPs provide a primary treatment, which is simply the removal of solid materials by mechanical means. 

Surfactants and their biotransformation products enter surface waters primarily through discharges from wastewater treatment plants (WWTPs). Depending on their physicochemical properties, surface-active substances may partition between the dissolved phase and the solid phase through adsorption onto suspended particles and sediments [1,2]. Several environmental studies have been dedicated to the assessment of the contribution of surfactant residues in effluents to the total load of surfactants in receiving waters. This contribution reviews the relevant literature describing the presence of linear alkylbenzene sulfonates (LASs) and in particular of their degradation products in surface waters and sediments (Table 6.3.1). 

An interesting vertical profile of the metabolite concentrations was observed the compounds showed a tendency to accumulate at the two-phase boundaries of air-freshwater and freshwater-saline water (the halocline). Thus, concentration maxima were observed at depths of 0 and 2 m (see Fig. 6.4.1) [6]. The observed distribution may result from either the physicochemical properties of these compounds (surface activity and hydrophobicity), or their formation at the interface due to increased biological activity. For the parent surfactants a similar but less pronounced vertical distribution pattern was observed (with maxima at 0 and 2 m of 17 and 9 xg L 1, respectively) [5],... 

The surfactant bioconcentration data available in the literature show considerable variability, due mainly to the different compounds, species, environmental characteristics and analytical procedures used to determine the BCF. Physicochemical properties of surfactants, such as molecular structure, molecular weight, partitioning coefficients (Kom Kqc), water solubility and sorption rate constants all influence their BCF [47]. 

Furuse, K., Ishizeki, C., and Iwahara, S. Studies on spermicidal activity of surfactants. I. Correlation between spermicidal effect and physicochemical properties of p-menthanylphenyl polyoxyethylene (8.8) ether and related surfactants. J. Pharm. Dyn. 1983, 6, 359-372. 

One of the problems associated with the study of the physicochemical properties of these materials is the lack of analytical methods of determining accurately their concentrations in dilute solution. In order to permit such determinations, an N-betaine type surfactant was synthesized with a benzyl group attached to the quaternary nitrogen. This permitted analysis of dilute aqueous... 

The difficulty with HLB as an index of physicochemical properties is that it is not a unique value, as the data of Zaslavsky et al. (1) on the haemolytic activity of three alkyl mercaptan polyoxyethylene derivatives clearly show in Table 1. Nevertheless data on promotion of the absorption of drugs by series of nonionic surfactants, when plotted as a function of HLB do show patterns of behaviour which can assist in pin-pointing the necessary lipophilicity required for optimal biological activity. It is evident however, that structural specificity plays a part in interactions of nonionic surfactants with biomembranes as shown in Table 1. It is reasonable to assume that membranes with different lipophilicities will"require" surfactants of different HLB to achieve penetration and fluidization one of the difficulties in discerning this optimal value of HLB resides in the problems of analysis of data in the literature. For example, Hirai et al. (8 ) examined the effect of a large series of alkyl polyoxyethylene ethers (C4,C0, Cj2 and C 2 series) on the absorption of insulin through the nasal mucosa of rats. Some results are shown in Table II. 

Stevens, P.J.G., Baker. E.A., and Anderson. N.H. Factors affecting the foliar absorption and redistribution of pesticides. 2. Physicochemical properties of the active ingredient and the role of surfactant, Pestic. Sci., 24(l) 31-53,1988. 

Wells, D. and Drummond, CJ. Nonionic n-hexyl, n-heptyl, and u-octyl urea surfactants some physicochemical properties, Langmuir, 15(14) 4713-4721, 1999. 

Electrokinetic chromatography (EKC) using microemulsion is one of the most powerful tools for the rapid measurement of log P w with high reproducibility. Because it is relatively easy to manipulate the pseudostationary phases of EKC, a lot of phases have been reported for the measurement not only of physicochemical properties but also of the separation selectivity, such as polymer micelles (64) and double-chain surfactant vesicles (56-58,60,61). These phases are also interesting in terms of the correlation to bioactivity. 

Sun JS, Foy CL (1996) Structurally related organosilicone surfactants, their physicochemical properties and effects on uptake and efficacy of primisulfuron in velvetleaf (Abutilon theophrasti Medicus). FRI Bulletin 193 225-230 (Proceedings of the fourth international symposium on adjuvants for agrochemicals, 1995)... 

Sjokvist E, Nystrom C, Alden M, Caram-Lelham N. Physicochemical aspects of drug release. XIY. The effects of some ionic and non-ionic surfactants on properties of a sparingly soluble drug in solid dispersions. Int J Pharm 1992 79 123-133. 

Ohlendorf D, Interthal W, Hoffmann H (1986) Surfactant systems for drag reduction physicochemical properties and rheological behaviour Rheol Acta 25 468... 

Weiss, J. 1999. Effect of Mass Transport Processes on Physicochemical Properties of Surfactant-Stabilized Emulsions. Department of Food Science, University of Massachusetts, Amherst. 280. 

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