Characterization of low T(g) synthetic polymers: I. Polymerization kinetics by mass spectrometry. II. Water induced structural reorganization of polymer surfaces by XPS

Low glass transition temperature (T_g) polymers that are based on silicones and fluorocarbons are of fundamental interest for tailoring surface properties of polymeric materials. These polymers play an increasingly important role in the design and implementation of advanced materials for applications ranging from biomedical devices to environmentally responsible coatings. As the demand for these advanced materials grows, so too does the need to better characterize the physical and chemical properties of these materials. This thesis utilizes several modern techniques to expand the understanding of the bulk properties, synthesis kinetics, and surface properties of this class of polymers.; The properties of synthetic polymers are dependent upon their respective molecular weights. Determining the molecular weight of polymers has been a challenge met by several techniques. The recent development of several new ionization sources has enabled mass spectrometry to become a powerful analytical method for studying the molecular weight of polymers. Time of flight secondary ion mass spectrometry (TOF-SIMS) and matrix assisted laser desorption ionization mass spectrometry (MALDI) were used in Chapter 1 to determine the molecular weight averages of two well defined poly(dimethylsiloxane) (PDMS) polymers. In addition to the molecular weight results, additional spectral features were observed that were indicative of kinetic information about the polymerization. These findings were the basis for the study in Chapter 2. The changes in these spectral features were investigated by TOF-SIMS and MALDI as a function of several reaction parameters.; X-ray photoelectron spectroscopy (XPS) is a powerful analytical surface instrument for studying polymer surface composition. The ultrahigh vacuum (UHV) environment in an XPS analysis chamber is generally well suited to study most polymer interfaces. However, some experiments require specialized apparatus to accommodate unconventional samples. Chapter 3 describes a temperature controllable sample manipulator that can be used to study a variety of samples at different temperatures. The main purpose of this apparatus is to study the water induced structural reorganization of a wide range of polymer surfaces. Chapter 4 uses this newly designed apparatus to study the influence of water on the surface composition of a series of novel perfluorinated triblock copolymers by XPS.