Surface Analysis
Knowing what is at the surface can be the clue to solving major problems in the detective work of trouble shooting. Surface analysis answers not only the questions of what and how much is on the surface but also gives a topological description of the surface.
Confocal Raman Microscopy
Confocal Raman microscopy offers the possibility to acquire chemical information of a sample with a resolution down to the optical diffraction limit (~ 250 nm). This method allows analyzing the local distribution of different components within a sample in ambient conditions and without requiring any special sample preparation.
Furthermore, differences in cristallinity and orientation of lattices can be determined as well as thicknesses of layers. This specific instrument is also equipped with Scanning Near-field Optical Microscopy (SNOM) and AFM (see below) for the determination of surface topography, elasticity, friction and adhesion.
The grant from Nils and Dorthi Troëdsson Foundation for the combined Confocal Raman/AFM equipment is gratefully acknowledged.
XPS (ESCA)
XPS (X-ray Photoelectron Spectroscopy), also known as ESCA (Electron Spectroscopy for Chemical Analysis), is a highly surface sensitive and powerful tool for chemical surface analysis. The XPS method provides quantitative chemical information - the chemical composition - for the outermost 2-10 nm of surfaces. The analysis depth depends on e.g. the material analyzed, and is about 10 nm for polymers and papers and lower for metal oxides and metals.
The grant from Knut and Alice Wallenberg foundation for the XPS instrument is gratefully acknowledged.
Atomic force microscopes (AFM)
In atomic force microscopy the surface is mechanically examined using a very sensitive tip. The information given is the surface topography. The technique has in later years developed to give information on surface rheology as well as frictional properties.
Profilometer
In a profilometer the surface is illuminated with white light and the surface topography is determined through the interference of the reflected light. The technique determines the surface topography on a larger scale compared with the AFM technique.
Wetting and contact angle
Determination of the wetting behavior of various liquids on a solid substrate gives surprisingly a wealth of information. First the wetting behavior is only sensitive to the outmost surface layer of the solid and it is hence an extremely surface sensitive analysis technique of the solid surface. Second, studies of wetting behavior can give information on the acid-base characteristics of the solid. Third, measuring the time dependence, gives dynamic information relevant for e.g. the printing process.