Atomic force microscopy was used for qualitative phase morphological mapping as well as quantitative investigation of surface forces measured at constituting blocks and clay regions of a thermoplastic elastomeric nanocomposite based on triblock copolymer: poly(styrene-ethylene-co-butylene-styrene) (SEBS) and organically modified nano-clay. The roughness and power spectral density analyses Of surface topography provided the increment in random roughness of the nanocomposite surface compared to pristine SEBS surface. The Same surfaces were examined by means of single point force-distance, and force-volume measurements. Large adhesive force of 25 nN and contact force of 260 nN were found in soft polyethylene (PEB) segments and higher cantilever deflection of 210 nm was found for clay regions of SEBS-clay nanocomposite. Mapping of elastic modulus of the glassy and rubbery blocks and clay regions was probed by employing Hertzian and JKR model from respective, approaching and retracting parts of force-distance curves. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 2104-2115, 2009