Advanced vibrational spectroscopy in surface analysis

In this licentiate thesis work a new non-destructive surface analysis method is introduced, which for the first time is based on total internal reflection (TIR) Raman spectroscopy and attenuated total reflectance infrared (ATR-IR) techniques. Together with the total internal reflection phenomenon, capable to acquiring information concerning the different molecular species present, the method creates opportunities to exploit new advanced applications. Over the past decades ATR-IR spectroscopy has become a well-known and routine method, and widely utilized in many laboratories, whereas the potential of TIR Raman spectroscopy has largely been neglected and therefore not fully exploited to date due to the predominant interest in other techniques, such as surface enhanced Raman spectroscopy (SERS). The principle of the method is illustrated in the first publication applied to the measurement of thin and ultra-thin polymer films (<100 nm). The technique was found to be an essential tool in analysing multi-layered polymer films, which have a soft substrate as the underlying layer. The separation/removal of ink components within a set thin offset ink film, following absorption into a porous coated paper substrate, is analysed in the second publication. Although the pore size distribution of the substrate was larger than the used probe depth the techniques provided information, regarding the retained portion of components in the ink film, which is an important advantage for paper design and print quality improvement. Critical design parameters, such as the required definition of providing sufficient capillary-driven offset ink component separation during setting, can be monitored to minimize the potential for printed image smearing and so to maximize the print rub resistance.