Monolayer deposition of bisphenol a polycarbonate oligomers on Au(111)
The deposition behavior of bisphenol A polycarbonate (BPA-PC) on a Au(111) single crystal has been studied. Thin films of PC were prepared by in situ evaporation of PC pellets under UHV conditions. The resulting PC/Au(111) interfaces were characterized by means of Ultraviolet Photoelectron Spectroscopy (UPS), X-ray Photoelectron Spectroscopy (XPS) and Scanning Tunneling Microscopy (STM). XPS and UPS revealed that no decomposition of the polymer takes place during evaporation. The C 1s and O 1s XPS core level analysis as well as the UPS spectra show distinct features which can be attributed to chemical bonding states of the PC molecule. Therefore, we conclude that the molecular structure within the monomeric unit remains intact after evaporation. Furthermore, STM measurements in the submonolayer regime revealed a self-assembly of small polymer chains of 2-4 monomeric units on the Au(111) surface.