Silicon-modified surfactants and wetting: IV. Spreading behaviour of trisiloxane surfactants on energetically different solid surfaces

✍ Scribed by R. Wagner; Y. Wu; H. v. Berlepsch; L. Perepelittchenko

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 155 KB
• Volume: 14
• Category: Article
• ISSN: 0268-2605
• DOI: 10.1002/(sici)1099-0739(200004)14:4<177::aid-aoc974>3.0.co;2-p

✦ Synopsis

The spreading behaviour of defined trisiloxane surfactants of general formula [(CH 3 ) 3 SiO] 2 CH 3 Si(CH 2 ) 3 (OCH 2 CH 2 ) n OCH 3 (n = 3-9) on five different solid surfaces has been investigated. Maximum spreading areas and rates are found on non-polar or slightly polar surfaces of 30 to 40 mN m À1 surface energy. Extremely low or high surface energies substantially reduce the spreading rates. On non-polar surfaces rapid spreading is observed for 1 wt % solutions of the relatively short-chained penta-and hexa-ethylene glycol derivatives. On slightly polar surfaces dilute 0.1 wt % solutions of longer-chained derivatives spread faster. This spreading pattern shift coincides with a change of the phase behaviour. Solutions of Silwet L77 do not prefer one specific surface, since 1 wt % solutions abruptly stop spreading after a few seconds and the maximum spreading rates are found for 0.1 wt % solutions. Therefore, Silwet L77 essentially belongs among the long-chained derivatives.