Emulsification solubilisation

The physico-chemical theory of surface activity is a vast field and no more than broad principles can be touched on here major reference sources exist for those who require more detail of the relationship between chemical structure and the various surfactant properties such as wetting, detergency and emulsification-solubilisation [32-36]. 

It is beyond the scope of this section to discuss the complex physico-chemical parameters of solubilisation in detail. Useful relevant works of reference are available [332-335]. It follows, however, that since solubilisation is essentially an extension of emulsification (or dispersion), the factors discussed in section 9.8.3 in regard to emulsification are also pertinent to solubilisation. Theory in this area is a useful guide but much still depends on... 

Due to their distinctive physico-chemical properties, non-ionic surfactants are applied in the fields of industry, processing technology and science, wherever their interfacial effects of detergency, (de)foaming, (de)emulsification, dispersion or solubilisation can enhance product or process performance. The characteristics of non-ionic surfactants that make them beneficial for detergents include their relatively low ionic sensitivity and their sorptive behaviour [17]. 

Solubilisation (or emnlsification) of dietary lipids is accomplished by means of bile salts, which are synthesised from cholesterol in the liver and then stored in the gallbladder they are emptied into the gnt following the ingestion of fat. Emulsification of dietary fats renders them accessible... 

Emulsification/absorption of dietary lipid in the intestine. Bile acids are stored in the gallbladder and released into the duodenum when cholecys-tokinin is released. In the small intestine, bile acids help to solubilise monoglycerides and fatty acids which are formed as the result of the digestion of dietary triglyceride, thereby enhancing the absorption of lipids and the fat-soluble vitamins A, D, E and K. 

Of these mechanisms, solubilisation and emulsification of soils are controlled by detergent composition, hydrodynamic flow is controlled by washing machine design and fibre flexing is controlled by fabric construction. The textile chemist can only influence the mechanisms that involve the fibre surface, i.e. rollup of oily soil, penetration of soil-fibre interface, surface abrasion and finish swelling. Finishes have been developed that provide soil release performance by taking advantage of all of these mechanisms. 

At the oil-rich side, the phase behaviour is inverted temperature-wise as can be seen in the T( wA)-section provided in Fig. 1.7(c). Thus, the near-critical phase boundary 2 —1 starts at low temperatures from the lower n-octane-QoEs miscibility gap (below <0°C) and ascends steeply upon the addition of water. With increasing wA, this boundary runs through a maximum and then decreases down to the upper critical endpoint temperature Tu. The emulsification failure boundary 1 —r 2 starts at high temperatures and low values of wA, which means that only small amounts of water can be solubilised in a water-in-oil (w/o) microemulsion at temperatures far above the phase inversion. Increasing amounts of water can be solubilised by decreasing the temperature, i.e. by approaching the phase inversion. At Tu the efb intersects the near-critical phase boundary and the funnel-shaped one-phase region closes. 

An accurate formulation handling is extremely useful not only to make microemulsion and to adjust their properties such as their solubilisation ability, or to attain a low interfacial tension to ease emulsification or to enhance oil recovery. Formulation has been shown to be also directly linked with emulsion properties such as their type, stability, viscosity, drop size [6] and with the efficiency of the emulsification protocol [7]. The existence and persistence of foams are dependent on formulation too [8]. Solid surface wetting is also linked with formulation as well as with many related applications. This is why an accurate numerical treatment of formulation issues is paramount in industrial research and development. 

Essential criteria for the preparation of emulsions, solubilisates and micro-emulsions will be dealt with in more detail below. On the subject of stabilisation and flocculation we will restrict ourselves to emulsions rather than dispersions in general as the basic laws are transferable. However, dispergates of solid particles are more difficult to treat than emulsions because of their often rough and inhomogeneous surface structure. With emulsions experimental complications arise over drop size distribution caused by the mechanical work input during emulsification, the nature of the emulsifier and by time, which is of considerable importance too. 

The measurement of the wave characteristics and application of Eq. (5.256) to experimental results allow to determine the surface parameters y and e. The dynamic surface elasticity is the most interesting property because it is connected with the kinetic coefficients of the relaxation processes in the system. The observed correlations between i2 and the efficiency of numerous processes of technological implication (foam formation [122], solubilisation of impurities [163], bubble formation [1], liquid spreading [163], emulsification [165]) are determined first... 

Devani, M., Ashford, M., Craig, D.Q., 2004. The emulsification and solubilisation properties of polyglycolysed oils in self-emulsifying formulations. J. Pharm. Pharmacol. 56, 307-316. 

It may also be mentioned that oriented micelles occur in solutions of Na des-oxycholate too . However the orientation of the molecules is in this case not so easily established as in soap solutions. The lipids exhibit a similar orientation We may pause a moment at the question of what factors determine the detergent action of soap solutions. We will only examine in more detail the solubilisation, as a result of which the dirt is dissolved and taken up into the micelles (for a review of the most important factors in detergent action — solubilisation, emulsification, protective action, base exchaii e, suspending action — see an important article by Me Baust in Advances of Colloid Science ). Hartley imagines that the organic material would be dissolved in the interior of the spherical soap micelles. 

P. A. Winsor, Hydrotropy, solubilisation and related emulsification processes. Part 1, Trans. Faraday... 

Winsor P. 1948. Hydrotropy, Solubilisation and Related Emulsification Processes. 1. to. 4. Transactions of the Faraday Society 376-398. 

---