To find an optimal formulation of oil-in-water (O/W) emulsions (/ o ¼ 0.05), the effect of emulsifier nature and concentration, agitation speed, emulsifying time, storage temperature and their mutual interactions on the properties and behavior of these dispersions is evaluated by means of an experimental design (Nemrodw software). Long-term emulsion stability is monitored by multiple light scattering (Turbiscan ags) and acoustic attenuation spectroscopy (Ultrasizer). After matching surfactant HLB and oil required HLB, a model giving the Sauter diameter as a function of emulsifier concentration, agitation speed and emulsification time is proposed. The highest stability of C 12 E 4 -stabilized O/W emulsions is observed with 1% emulsifier.

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Nickel coatings were obtained from Watts bath containing sodium dodecyl sulfate (SDS) or polyvinylpyrrolidone (PVP) surfactants by direct current plating. The influence of electrolysis parameters, temperature, current density, concentration of surfactants and pH on the nickel deposits brightness is investigated through a multiple linear regression model with interaction. The models obtained fitted very well the experimental data. ANOVA statistical analysis shows that all design factors are significant, and the brightness of nickel deposits obtained from bath containing PVP is more sensitive to the changes in the factors levels. The electrochemical behaviour of baths was discussed; the results revealed an inhibitive effect exerted by both SDS and PVP. We have also found that the brightness and the inhibition are well linked and directly proportional. In addition, the corrosion resistance of the nickel coatings was slightly improved, especially with PVP. Finally, the optimization analysis showed that PVP could efficiently and eco-friendly substitute SDS as an additive of nickel electroplating.

The cloud point temperature, Tc, of commercial nonionic surfactants: poly(oxyethylene) alkyl ethers normalCnnormalcnormalHnnormale (case: dodecan‐1ol polyethoxylate, with the middle chemical structure n‐C12E6) was predicted by applying the Flory–Huggins theory for polymer solutions, adapted to alcohol ethoxylates aqueous solutions by Rupert and using the pseudo‐phase model original developed for micro‐emulsions diagrams composition. The variations of interaction enthalpy as a function of carbon chain length and number of ethylene oxide units are also modelled. The expression of Tc as the function of the composition was derived assuming the regular solution for mixed micelles. The experimental results of the cloud point obtained for mixtures of n‐C12E6 was better reproduced by the pseudo‐phase model, which requires more specific surfactant data (the critical micelles concentration, cmc; critical temperature TC), and a minimum of experimental data.