THE INFLUENCE OF MIXTURE ANIONIC AND NONIONIC SURFACTANTS ON THE SURFACE FREE-ENERGY OF CASSITERITE

The measurements of the contact angle were made for water, glycerol, f ormamide, diiodomethane and bromoform on a cassiterite surface covered with a mixed film of SDS and TX-100 formed by adsorption from solutio n of SDS and TX-100 at different molar fraction at a constant concentr ation equal to 2 x 10(-4) m. Using the contact angles the dispersion a nd non-dispersion or Lifshitz-van-der-Waals and acid base components o f the surface free energy of cassiterite covered with a mixed film of SDS and TX-100 were evaluated. These components were compared to those for a ''bare'' cassiterite surface. Also, the electron-acceptor and e lectron-donor parts of the acid-base components were determined. On th e basis of the measurements and calculations synergetic effects were f ound in the wettability and surface free energy of cassiterite when it was covered with the mixed film.