We present a study of polystyrene-metal interfaces and discuss the relationship between the interfacial structure and anomalies in the measured glass transition temperature (
T g) of thin metal capped polystyrene (PS) films. The PS films used in these studies were coated with an evaporated metal layer of either Aluminum (Al) or gold (Au) and the T gvalues were measured with ellipsometry. Uncoated PS films were also measured and these samples showed T gvalues that were reduced relative to the bulk value for film thicknesses ( h) less than 40 nm. Films coated with Au were shown to have measured T gvalues that were the same as the bulk value ( T gbulk=370 K) for all the film thicknesses studied ( h≥ 8nm). The Al coated PS films had measured T gvalues that were the same as the uncoated PS films. The observed differences are discussed in terms of the differences in the structure of the metal-polymer interfaces produced during thermal evaporation of the metal layers. A novel sample preparation procedure was developed to enable us to use Atomic Force Microscopy (AFM) to directlymeasure the structure of the buried polymer-metal interfaces. The measurements performed on these systems support the suggestion that the interfacial structure is different for the two metal-polymer interfaces studied and that these differences may be the cause of the anomalies in the measured T gs of these samples.