Zwitterionic surfactants emulsions

The development of monoalkyl phosphate as a low skin irritating anionic surfactant is accented in a review with 30 references on monoalkyl phosphate salts, including surface-active properties, cutaneous effects, and applications to paste and liquid-type skin cleansers, and also phosphorylation reactions from the viewpoint of industrial production [26]. Amine salts of acrylate ester polymers, which are physiologically acceptable and useful as surfactants, are prepared by transesterification of alkyl acrylate polymers with 4-morpholinethanol or the alkanolamines and fatty alcohols or alkoxylated alkylphenols, and neutralizing with carboxylic or phosphoric acid. The polymer salt was used as an emulsifying agent for oils and waxes [70]. Preparation of pharmaceutical liposomes with surfactants derived from phosphoric acid is described in [279]. Lipid bilayer vesicles comprise an anionic or zwitterionic surfactant which when dispersed in H20 at a temperature above the phase transition temperature is in a micellar phase and a second lipid which is a single-chain fatty acid, fatty acid ester, or fatty alcohol which is in an emulsion phase, and cholesterol or a derivative. 

Surfactants or emulsifiers help stabilize the emulsion and are classified into four broad categories anionic, cationic, nonionic, and zwitterionic. Surfactants are dissolved in water at low concentrations, where they form aggregates or micelles. At a concentration greater than their critical micelle concentration (CMC), all excess molecules form micelles. 

Emulsions are a class of disperse systems consisting of two immiscible liquids, one constituting the droplets (the disperse phase) and the second the dispersion medium. The most common class of emulsions is those whereby the droplets constitute the oil phase and the medium is an aqueous solution (referred to as O/W emulsions) or where the droplets constitute the disperse phase, with the oil being the continuous phase (W/O emulsions). To disperse a liquid into another immiscible liquid requires a third component, referred to as the emulsifier, which in most cases is a surfactant. Several types of emulsifiers may be used to prepare the system, ranging from anionic, cationic, zwitterionic, and nonioinic surfactants to more specialized emulsifiers of the polymeric type, referred to as polymeric... 

There are an enormous variety of commercial emulsifiers that are employed in emulsion polymerization. Emulsifiers are generally categorized into four major classes anionic, cationic, nonionic and zwitterionic (amphoteric). The anionic and nonionic emulsifiers are the most widely used. In addition, mixtures of emulsifiers are also often used. Since the effects of the molecular structme and chemical and physical properties of an emulsifier on particle formation are still far from being well understood, numerous experimental investigations on particle formation have been carried out to date with various nonionic emulsifiers [99-102], mixed emulsifiers (ionic and nonionic emulsifiers) [18,103-106] and reactive surfactants [33, 107-110]. Recently, polymeric surfactants have become widely used and studied in emulsion polymerizations [111-116]. A general review of polymeric surfactants was published in 1992 by Piirma [117]. Recently, emulsion polymerization stabilized by nonionic and mixed (ionic and nonionic) emulsifiers was reviewed by Capek [118]. 

Emulsions are dispersions of one liquid in another liquid, most commonly water-in-oil or oil-in-water. The total interfacial area in an emulsion is very large, and sinee flie interfacial area is associated with a positive free energy (the interfacial tension), the emulsion system is thermodjmam-ically unstable. Nevertheless, it is possible to make emulsions with an excellent long-term stability. This requires the use of emulsifiers that accumulate at the oil/water interface and create an energy barrier towards flocculation and coalescence. The emulsifiers can be ionic, zwitterionic, or nonionic surfactants, proteins, amphiphilic polymers, or combinations of polymers and surfactants. The structure of the adsorbed layer at the water/oil interface may be rather complex, involving several species adsorbed directly to the interface as well as other species adsorbing on top of the first layer. 

Synonyms Amides, palm oil, N-(2-hydroxypropyl)- N-(2-Hydroxypropyl) palm oil acid amide Monoisopropanolamine palm oil acid amide Palm oil acid amide, N-(2-hydroxypropyl)- Palm oil acid monoisopropanolamide Definition Mixt. of isopropanolamides of the fatty acids derived from palm oil Formula RCONHCH2CH3CHOH where RCO- rep. fatty acids derived from palm oil Uses Emulsifier, emulsion stabilizer, surfactant, vise, control agent in cosmetics Palmamidopropyl betaine Synonyms 1-Propanaminium, N-carboxymethyl-N,N-dimethyl-3-amino-, N-(palm-oil acyl) derive., hydroxides, inner salts Classification Zwitterion (inner salt)... 

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