Wettability and surface free energy of glass in the presence of cetyltrimethylammonium bromide

Measurements of contact angles for water, aqueous solution of cetyltrimethylammonium bromide (CTAB), glycerol, formamide and diiodomethane on the glass slide covered with CTAB him formed from the CTAB solution in the range of its concentration from 10(-8) to 10(-3) M were made. Using the obtained results, the Lifshitz-van der Waals and acid-base components and the electron-acceptor and electron-donor parameters of the surface free energy of glass slide covered with CTAB him were determined. Also, the wetting critical surface tension of glass slide covered with CTAB him was determined and the value of the critical surface tension was found to correspond to the surface free energy of glass slide covered with CTAB film formed from CTAB aqueous solution in the concentration range from 6 x 10(-5) to 10(-3) M. It was also found that the components and parameters of the surface free energy of glass slide covered with CTAB film determined from contact angles of glycerol, formamide and diiodomethane are more reliable than those determined from the contact angles for two sets of three liquids, including water (water-glycerol-diiodomethane and water-formamide-diiodomethane). The components and parameters of the surface free energy of glass in the presence of CTAB indicate that the surface active ions in the first monolayer are oriented parallel to the glass surface with the polar beads sloping towards it and in the second monolayer the heads are sloping towards the liquid phase. (C) 1999 Elsevier Science S.A. All rights reserved.