XPS Investigation of the Spherulite Surface for Poly(ε-caprolactone)/poly(vinyl chloride)

Recently, polymer thin films have been increasingly used in microelectronic applications. Poly(ε-caprolactone)/poly(vinyl chloride) (PCL/PVC) blends are widely studied polymers. When PCL and PVC are blended in certain ratio, ring-banded spherulites are formed and the blends are often composed of a PCL crystal phase and a PCL/PVC amorphous phase. Optical microscopy, atomic force microscopy and angle-dependent XPS analyses were used by many scientists to investigate the morphology and composition of the PCL/PVC films. Using XPS and imaging XPS analyses, we have investigated the surface chemical composition and elemental distribution of PCL/PVC films. The results show that PCL enriches to the PCL/PVC polymer-air interface. Besides, the imaging XPS analysis indicates that PVC is concentrated at the spherulite boundaries and the width of the boundaries is about 15 μm. These observations may be valuable for the explanation of the crystallization and morphological behaviors of polymer blends.