Micellization of Nonionic Surfactant Dimers and of the Corresponding Surfactant Monomers in Aqueous Solution

✍ Scribed by Gregory Paddon-Jones; Sudarshi Regismond; Klaus Kwetkat; Raoul Zana

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 83 KB
• Volume: 243
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.2001.7849

✦ Synopsis

Two nonionic surfactant dimers (gemini surfactants) of the dimethylene 1,2-bis(N-polyethyleneglycol dodecylamide) type and the corresponding surfactant monomers of the N-methyl, Npolyethyleneglycol dodecylamide type have been synthesized with an increasing number of ethyleneglycol (EG) units in the head group. Their micellization behavior in aqueous solution has been investigated. The cloud temperature, cmc, and micelle aggregation number have been measured using turbidity, surface tension, pyrene fluorescence probing, and time-resolved fluorescence quenching. The results permitted the first direct comparison between the micellar properties of nonionic surfactant monomers and dimers having polar head groups of the polyethyleneglycol type. The nonionic surfactant dimers are more efficient and effective at reducing the surface tension of water and are characterized by a lower cloud temperature, a lower cmc (by about one order of magnitude), and larger micelle aggregation numbers than the corresponding surfactant monomers. Overall the effect of the number of EG units on the micellar properties of the synthesized surfactants has been found to be very similar to that reported for conventional nonionic surfactants of the polyethyleneglycol monododecylether type.