The blend surface of polyamide 6 and polytetrafluoroethylene (PA 6/PTFE) and its change as a function of annealing time are investigated by means of attenuated total reflection (ATR)-FTIR spectroscopy, contact angle (CA) measurement, as well as atomic force microscopy (AFM) under ambient condition; meanwhile the surface elemental compositions are obtained by X-ray photoelectron spectroscopy (XPS). The results show that the addition of fluoro content can decrease the surface energy compared with the pure polyamide, while, an evident influence on the surface energy has not been detected with increasing fluoro contents. Upon annealing at 120 degrees C, there is a profound enrichment of the low-surface energy component to the sample surface; yet this situation becomes more complex when samples are annealed at 150 degrees C-not only the segregation effect from the low surface energy PTFE, but also the crystallization of the PA 6 will come into play for the blend with 50% PTFE. These observations are ascribed to the presence of the polar group of the polyamide component, as well as its strong tendency to crystallize when subjected to thermal treatment at sufficiently high temperatures, and this behavior would basically offset the segregation tendency of fluoro component to the sample surface. This assumption is further corroborated by the XPS measurement in the current researches. (c) 2006 Wiley Periodicals, Inc.