SURFACE ANALYSIS Introduction The surface properties of polymers are important in many applications and they are dependent on the structure and composition of the outermost molecular layers. The surface layer thickness involved is typically of the order of a few nanometers. Understanding surface structure–property relationships therefore requires analytical techniques which have this degree of surface sensitivity (or speciﬁcity). Two techniques stand out: X-ray photoelectron spectroscopy (XPS) (1), also known as ESCA (electron spectroscopy for chemical analysis), and secondary ion mass spectrometry (SIMS) (2). The information provided by these methods is highly complementary and they are frequently used in combination. This article describes the physical bases and analytical capabilities of XPS and SIMS and illustrates their application in polymer surface characterization (3).
X-ray Photoelectron Spectroscopy Physical Basis. In XPS, the sample inside a high vacuum system (pressure