Superspreading, Skein Wetting, and Dynamic Surface Tension
1996; American Chemical Society; Volume: 12; Issue: 20 Linguagem: Inglês
10.1021/la9602731
ISSN1520-5827
Autores Tópico(s)Pickering emulsions and particle stabilization
ResumoA study has been made of the spreading of 0.1% aqueous solutions of "superspreading" trisiloxane surfactants, especially the one made with 7.5 mol of ethylene oxide (L-77), on the hydrophobic surface Parafilm, their dynamic surface tension, and their Draves skein wetting time. No relationship was found between "superspreading" and Draves Skein wetting. The low surface tension of the wetting solution at short time (<0.2 s) is one of the critical conditions for good Draves skein wetting, while a surface tension of 21 mN/m appears to be a necessary but not sufficient requirement for superspreading. The presence of dispersed particles in the solutions is not a requirement for superspreading. The replacement of a portion of the L-77 in the solution by certain alkyl chain nonspreading materials can produce greater superspreading than shown by the former (synergy in superspreading). Synergistic materials contain alkyl chains with less than 10 carbon atoms and can have either one or two hydrophilic and hydrophobic groups. The enhancement of superspreading is not associated with further lowering of the surface tension of the solution but may be related to the attractive interaction between the two solutes.
Referência(s)