The detailed understanding of the surface and interface physicochemical aspects of intercalated organo-bentonite is of importance in the design of organoclay based materials and in their industrial applications. In this study X-ray photoelectron spectroscopy (XPS), diffuse reflectance infrared Fourier transform spectra (DRIFT), X-ray diffraction (XRD) have been used to provide new insights into the surface composition, surface functional groups, interlayer structure and morphology of hexadecyl trimethyl ammonium bromide (HDTMAB)/bentonite organoclays (oMMT). Inverse gas chromatography (IGC) is used for understanding the effect of the HDTMAB on the dispersive component of the surface energy (gamma(d)(s)) which is closely related with the adhesion and wettability properties of materials. The increasing amount of HDTMAB in organoclays was found to significantly reduce the gamma(d)(s) values up to 1.5 oMMT. 1.5 oMMT and 2 oMMT values were found so closer to each other. More importantly, the gamma(d)(s) values were correlated with the XPS-determined surface N/Al atomic ratio, taken as a chemical descriptor for the modification of the clay. (C) 2014 Elsevier Ltd. All rights reserved.