Surface-active agents surfactants cationic

The surface active agents (surfactants) may be cationic, anionic or non-ionic. Surfactants commonly used are cetyltrimethyl ammonium bromide (CTABr), sodium lauryl sulphate (NaLS) and triton-X, etc. The surfactants help to lower the surface tension at the monomer-water interface and also facilitate emulsification of the monomer in water. Because of their low solubility surfactants get fully dissolved or molecularly dispersed only at low concentrations and at higher concentrations micelles are formed. The highest concentration where in all the molecules are in dispersed state is known as critical micelle concentration (CMC). The CMC values of some surfactants are listed in table below. 

A third class of industrial chemical biocides consists of agents with the ability to inhibit biological film formation, also called surfactants . The term surfactant originates from the phrase surface active agent. Surfactants fall into four broad categories anionic (e.g., soaps, alkyl benzenesulfonates, alkyl sulfonates, alkyl phosphates), cationic (e.g., quaternary ammonium salts), nonionic (e.g., alkyl polyglycosides, alcohol ethoxylates, alkylphenol ethoxylates), and zwitterionic. 

Surface-active agents iacrease the conductivity of oils quite significantly (97), and addition of water, probably dissolved at the iaterface with the surfactant, further iacreases the conductivity. Nonionic and cationic surface-active agents are preferred to anionic surface-active agents probably because of their higher solubiHty ia oils and higher hygroscopicity. Many anionic surfactants have adequate antistatic efficiency, but they are used less frequendy. 

Cationic surfactants are surface-active agents that have one or more functional groups in their molecule that ionise in aqueous solution to produce positively charged organic ions. The most representative cationic surfactants are quaternary ammonium derivatives in which the N atom is bonded to four alkyl groups. For many years, ditallow dimethylammonium chloride (DTDMAC) has been the most widely used product of this family. Its recalcitrance to biodegradation, however, has... 

Structure Formation in Surfactant Solutions. Surfactants, also referred to as soaps, detergents, tensides, or surface active agents, are amphiphilic molecules possessing both hydrophilic and hydrophobic regions. They can be classified as anionic, cationic, zwitterionic, or nonionic (neutral) depending upon the nature of the polar... 

L. K. Wang, M. H. S. Wang, S. Yaksich, and M. L. Granstrom, Water treatment with multiphase flow reactor and cationic surfactants, J. Am. Water Works Assc. 70, 522-528 (1978). V. Kondratazicius, Removal of synthetic surface-active agents from waste waters of tanneries, Kozk. Obur. Prom. (USSR) 11, 18-18 (1969). 

Although it might be thought that its CIS side chain would make cardanol an ideal candidate for surface active agents comparatively few developments have materialised. The use of CNSL as a potential source of surfactants and additives has been briefly reviewed (ref. 280). The Mannich reaction of cardanol with dialkylamines and formaldehyde (ref. 281) and the formation of cationics such as 3-pentadecyl-6-dimethylaminomethyl methosulphate has been described (ref. 2). 

The surface-active part of cationic surfactants bears positive charge. Cationic surfactants are nonbiodegradable and are used as bactericides. Due to the tendency to be adsorbed at negatively charged surfaces, they are anticorrosive and antistatic agents. Examples of cationic surfactants are enlisted in Table 13.4. 

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