In this thesis, hybrid methods for nanoscale characterization of heterogeneous thin polymer films were discussed. Essentially two ellipsometry based hybrid methods were established or further developed, respectively, namely electrochemical imaging ellipsometry (EC-IE) and scanning near field ellipsometry microscopy (SNEM). Ellipsometry was combined with electrochemical methods for the visualization of redox driven dynamic changes in thin polymer films. In particular, the redox responsive behaviour of an oligoethylene sulfide end-functionalized poly(ferrocenyldimethylsilane) (ES-PFS) film was investigated with this hybrid method against a passive (non-redoxactive) 11-mercapto-1- undecanol (MCU) layer. The thickness change of the PFS layer upon oxidation and the reduction was observed in situ in real time with EC-IE. This hybrid method provides vertical resolution at the sub nanometer scale while its lateral resolution is limited to the wavelength of the light source (λ=633 nm). In contrast, SNEM reveals lateral resolution below the diffraction limit of the light. The emphasis of the thesis was devoted to SNEM, including the introduction of the instrument, experimental case studies to enlighten its contrast formation and the optimization of the method. SNEM enables optical contrast imaging of thin transparent polymer films at the nanoscale due to the combination of the spatial tip-sample positioning capability of the atomic force microscopy (AFM) together with the high sensitivity of ellipsometry.
|Award date||26 Sep 2014|
|Place of Publication||Enschede|
|Publication status||Published - 26 Sep 2014|