Dynamic contact angles on PTFE surface by aqueous surfactant solution in the absence and presence of electrolytes

Rajib Ghosh Chaudhuri; Santanu Paria

doi:10.1016/j.jcis.2009.05.033

Dynamic contact angles on PTFE surface by aqueous surfactant solution in the absence and presence of electrolytes

J Colloid Interface Sci. 2009 Sep 15;337(2):555-62. doi: 10.1016/j.jcis.2009.05.033. Epub 2009 May 21.

Authors

Rajib Ghosh Chaudhuri¹, Santanu Paria

Affiliation

¹ Department of Chemical Engineering, National Institute of Technology, Rourkela 769 008, Orissa, India.

PMID: 19505694
DOI: 10.1016/j.jcis.2009.05.033

Abstract

This study presents the experimental results on dynamic contact angles of pure surfactants and surfactants with electrolyte solutions on PTFE (Teflon) surface. Dynamic advancing (theta(A)) and receding (theta(R)) contact angles measurements by the Wilhelmy plate technique were carried out for aqueous solution of three different surfactants Triton X-100 (TX-100), sodium dodecylbenzene sulfonate (SDBS), and cetyltrimethylammonium bromide (CTAB). The same measurements in the presence of different electrolytes NaCl, Na(2)SO(4), and CaCl(2) for ionic surfactants (SDBS and CTAB) were also carried out to see the change in contact angle and wetting behavior. The presence of electrolytes changes the advancing contact angle as well as wetting properties of hydrophobic solid surface significantly even at very low surfactant concentration. Counter ion valency of the electrolyte is more important in reducing advancing contact angle on hydrophobic PTFE surface at very low concentration of ionic surfactants from CMC. Pure surfactants and ionic surfactants in the presence of electrolytes show a linear relationship between the adhesional tension and surface tension at air-water interface with different slope and intercept.