Molar adsorption free energies, adsorption enthalpies, and entropies of n-alkanes (C6-C10) and eight polar compounds possessing different donor-acceptor properties on the surface of titanium dioxide (rutile form) and TiO2, modified by sequential coating with amorphous Al2O3 (4% w/w) and SiO2 (2% w/w) were measured by inverse gas chromatography. It has been established that modification of the rutile surface leads to an increase of the dispersive component of the surface free energy as well as of the donor and acceptor characteristics of the solid and its relative acidity.