SURFACE CHARACTERIZATION OF SEGMENTED SILOXANE URETHANE BLOCK-COPOLYMERS

New siloxane-urethane block copolymers were synthesized and the effect of a siloxane moiety on microphase segregation in soft/hard block cop olymers was studied by several analytical methods. Scanning electron m icroscopy/energy dispersive spectroscopy (SEM/EDS) provided topographi cal and bulk composition information. Electron Spectroscopy for Chemic al Analysis (ESCA) provided surface chemical information. Fourier Tran sform Infrared Spectroscopy (FT-IR) provided chemical bond information for the near-surface region. Thermogravimetric Analysis (TGA) provide d information concerning the thermal stability of the polymers. Differ ential Scanning Calorimetry (DSC) provided information on the soft and hard block segments within the polymer. These studies showed that the block copolymer contained an enhanced silicone-containing surface. Fo r films cast on glass, less silicon was detected in the bulk (exposed by physically removing the surface material), and on the backside (gla ss) of the polymer film, than on the air-exposed surface. Of particula r interest is the fact that data also show that the solvents, from whi ch the polymers were cast, have a significant influence on microphase segregation. The films cast from THF have higher silicone concentratio ns at the surface as compared to polymers cast from DMAC/CH2Cl2 or dio xane.