Advantages emulsifying properties

Emulsions of fatty- and petroleum-based substances, both oils and waxes, of the o/w type are made by using blends of sorbitan fatty esters and their poly(oxyethylene) derivatives. Mixtures of poly(oxyethylene(20)) sorbitan monostearate (Polysorbate 60) and sorbitan monostearate are typical examples of blends used for lotions and creams. Both sorbitan fatty acid esters and their poly(oxyethylene) derivatives are particularly advantageous in cosmetic uses because of their very low skin irritant properties. Sorbitan fatty ester emulsifiers for w/o emulsions of mineral oil are used in hair preparations of both the lotion and cream type. Poly(oxyethylene(20)) sorbitan monolaurate is useflil in shampoo formulations (see Hairpreparations). Poly(oxyethylene) sorbitan surfactants are also used for solubilization of essential oils in the preparation of colognes and after-shave lotions. 

For the characterization of Langmuir films, Fulda and coworkers [75-77] used anionic and cationic core-shell particles prepared by emulsifier-free emulsion polymerization. These particles have several advantages over those used in early publications First, the particles do not contain any stabihzer or emulsifier, which is eventually desorbed upon spreading and disturbs the formation of a particle monolayer at the air-water interface. Second, the preparation is a one-step process leading directly to monodisperse particles 0.2-0.5 jim in diameter. Third, the nature of the shell can be easily varied by using different hydrophilic comonomers. In Table 1, the particles and their characteristic properties are hsted. Most of the studies were carried out using anionic particles with polystyrene as core material and polyacrylic acid in the shell. 

Advantages Surface hydrophobicity is often positively correlated with emulsifying and foaming properties of a protein. 

Poly(ethylene oxide) (PEO) macromonomers constitute a new class of surface active monomers which give, by emulsifier-free emulsion polymerization or copolymerization, stable polymer dispersions and comb-like materials with very interesting properties due to the exceptional properties of ethylene oxide (EO) side chains. They are a basis for a number of various applications which take advantage of the binding properties of PEO [39], its hydrophilic and amphipathic behavior [40], as well as its bio compatibility and non-absorbing character towards proteins [41]. Various types of PEO macromonomers have been proposed and among them the most popular are the acrylates and methacrylates [42]. 

An illustration of the application of an emulsified liquid bandage is shown in Fig. 2.5. The microscopic view of this film formation shows microscopic spherical particles coalescing to form a continuous film. The advantage of the emulsion is that it is a waterborne and contains no solvents (i.e., organic solvents) which is preferred over organic solvents for the biocompatible property. 

Some researchers are exploring a totally different approach to the production of artificial blood that focuses on the synthesis of nonnatural substances with bloodlike properties. This approach has the advantage of avoiding the use of human or animal blood or any of its components. One line of research makes use of a class of chemicals known as the perfluorocarbons (PFCs), hydrocarbons in which all hydrogens have been replaced by fluorine atoms. The first PFC to be marketed commercially was called Fluosol-DA, manufactured by the Green Cross Corporation of Japan. Fluosol-DA was a mixture of perfluorodecalin (C10F18) and perfluorotripropylamine (CgF21N) emulsified with Pluronic F-68, a copolymer of oxyethylene and oxy-propylene. 

Control of Drop Size w/o Emulsions. Although the control of the drift of herbicide sprays was the initial reason for renewed interest in water-in-oil emulsion sprays, there are other interesting and novel ways of applying pesticides. The physical properties of w/o emulsions are considerably different from those of more conventional types of spray liquids, and the emulsifiers required to form and stabilize w/o emulsions are different from the usual materials employed in oil-in-water and wettable powder sprays. These differences can affect all aspects of spray performance, and a thorough study is required to appreciate the advantages and disadvantages which w/o emulsions may possess over aqueous-based sprays. 

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