Amphoteric surfactant, definition

Amphiphilic compounds as surfactants, 21 Amphoteric surfactant, definition, 386 Analysis speed, importance, 125 Anionic surfactants definition, 387... 

For shampoos, shaving foams and tooth pastes, high stability and definite foam structure is one of the main factors determining the commercial value of the product. In this connection, conventional shampoos include anionics (ammonium or triethanolamine salts of alkylsulphates mixed with alkylolamides of natural fatty acids, e.g. coconut oil acids, as well as amphoteric surfactants and hydrolysed proteins. Detailed patent data on the formulations are given in [80, 110] and other reviews. 

Amphoteric surfactants are a class of chemicals whose functionality and utility to the industry is showing definite growth. As a class of surfactants, they are safe, both functional and with low irritation potentials for consumer products and, consequently, are finding increased use in personal products. The wide range of chemistries that are encompassed by this class of surfactant afford product development chemists the opportunity to tailor the performance of their products for specific applications. This is evident by the broad range of industries interested in these technologies. 

Amphoteric surfactants by definition are chimeric, exhibiting anionic character in alkaline solution, nonionic character near their isoelectric point, and cationic character in acidic solution [73]. As a result of their complex charge characteristics, their interactions with interfaces must be examined iudividually and as a function of pH. For example, the adsorption of alkyl betaines firom solution onto wool keratin is much greater at acidic than alkalide pH values. Although amphoteric surfactants are used extensively to improve the cosmetic attributes of many consmner products [74], their interactions with skin have received little attention. 

The two distinctive affinities in the surfactant molecule mentioned above serve as the basis for the commonly accepted definition of surfactant groups. According to the charge of their hydrophilic moiety, surfactants can be classified into four categories anionic, non-ionic, cationic and amphoteric. 

RC0NHCH2CH2NCH2C00NaCH2CH20CH2C00 Na, RCO- = tallow fatty acids Properties Amphoteric Uses Surfactant in cosmetics Trade Name Synonyms Rewoteric AM 2T t[Goldschmidt http //www.goldschmidt.com] Disodium tallowiminodipropionate CAS 61791-56-8 EINECS/ELINCS 263-190-6 Synonyms P-Alanine, N-(2-carboxyethyl)-, N-tallow alkyl derivs., disodium salts N-(2-Carboxyethyl)-N-(tallow acyl)-p-alanine Disodium N-tallow-p iminodipropionate Definition Disodium salt of a substituted propionic acid... 

CiyHssCONHCHzCHzNCHzCHzOHCHzCHzCOONa Properties Amphoteric Toxicology TSCA listed Uses Surfactant, conditioner, lubricant, thickener in cosmetics and industrial prods. Trade Name Synonyms Monateric ISA-35 [Uniqema Am. http //www.uniqema.com], Schercoteric l-AA [Scher http //www.scherchem.com] Chesham Chems. Ltd http //www. cheshamchemicals. co. uk] Sodium isostearoyl lactylate CAS 66988-04-3 EINECS/ELINCS 266-533-8 Synonyms Sodium 2-(1-carboxylatoethoxy)-1-methyl-2-oxoethyl isooctadecanoate Definition Sodium salt of the isostearic acid ester of lactyl lactate Empirical C24H44O6 Na Formula CiyHssCOOCHCHaCOOCHCHsCOONa Properties Anionic... 

Cationic surfactants represent one of the smaller classes of surfactants, with a consumption estimated to be 700000 tons per year. Typically, reviews and market studies include in this class of materials all amine-based surfactants, whether they be charged or uncharged. In this present chapter we will use the same definition, but exclude amphoteric materials, which will be covered in the next chapter in this volume. 

Definition Propionic acid salt of lauramidopropyidimethylamine Empirical C,7H3gN20 C3Hg02 Formula CH3(CH2),oCONH(CH2)3N(CH3)2.HOOCCH2CH3 Uses Antistat surfactant for industrial cleaners and personal care prods. Manuf./Distrib. Somerset Cosmetic Co. Variati Lauramidopropyl dimethyl betaine Ionic Nature Amphoteric... 

Definition Sodium salt of the ester of tartaric acid with laureth-7 Ionic Nature Nonionic Empirical CjjHjgO, Na Uses Surfactant, detergent in cosmetics Features Nonirritating ManufJDistrib. Nanjing Chemlin Sodium lauriminodipropionate CAS 14960-06-6 26256-79-1 EINECS/ELINCS 239-032-7 Synonyms N-(2-Carboxyethyl)-N-dodecyl-P-alanine, monosodium salt Sodium N-(2-carboxyethyl)-N-dodecyl-P-alaninate Sodium N-lauryl-P-iminodipropionate Definition Partial sodium salt of a substituted propionic acid Ionic Nature Amphoteric Empirical C H35N04-Na... 

The family of surfactants commonly referred to as amphoterics are surface-active materials that contain, or have the potential to form, both positive and negative functional groups under specified conditions. Their definition as a separate class of surfactants has historically been somewhat controversial, since they may be electrically neutral and their general properties under many conditions make them functionally similar to some nonionic surfactants. For purposes of discussions related to chemical structures, however, they have been separated into a distinct family. In the final analysis, a surfactant by any other name is still a surfactant, so that too much importance should not be placed on nomenclature. 

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