SEDL / STP / STP1347-EB / STP14161S

Trisiloxane Surfactants — Mechanisms of Spreading and Wetting

Venzmer, J
Technical Manager, Th. Goldschmidt AG, Essen,

Wilkowski, SP
Technical Manager, Goldschmidt Chemical Corp., Hopewell, VA

Pages: 12    Published: Jan 1998

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Abstract

Aqueous solutions of some nonionic trisiloxane surfactants exhibit superior wetting properties on hydrophobic substrates (“superspreading”). Although this phenomenon has received extensive coverage in the scientific literature in recent years, its mechanism and the reason why only some silicone surfactants show this behavior remained unclear. Apart from the characteristic of a low surface tension, which is typical of most silicone surfactants, it is crucial that the surfactants form bilayer aggregates (vesicles, lamellar phases) in aqueous solution. Based on molecular packing considerations, there is a fundamental difference between the behavior at the solid/liquid interface of a micelle-forming surfactant and of a vesicle-forming surfactant. The model presented is supported by measurements of the spreading kinetics.