The present paper reports on the formation and respectively shielding of TiO2 nanotubes elaborated in two water-containing organic electrolytes with the addition of NH4F, via potential step anodizing method. The organic compounds used ethylene glycol (EG) and polyethylene glycol (PEG), have significantly different molecular weights and viscosities. As a consequence, the resulting nanotubes layers are unshielded in first electrolyte and shielded in the second and have different diameters and lengths. FT-IR spectra reveal the incorporation of electrolyte anions to the surface of the TiO2 nanotubes when employing the most viscous electrolyte. This could be an explanation for different contact angle values, roughness and corrosion resistance in bioloquids. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.035302jes] All rights reserved.