Pilot Experiments for Nano Characterization of Sustainable Coatings using Synchrotron InfraRed Imaging

Important results from the project

The aim of the project was to use Nano-IR spectroscopy and chemical imaging at the nano-level to increase the knowledge of the degradation mechanisms of tape varnished paints. New paint systems where fossil-based chemicals are replaced with bio-based components make it necessary to better understand degradation mechanisms so that more resistant and durable paints can be developed. However, the measurements with Nano-IR spectroscopy and high-resolution chemical imaging were only partially successful due to low sensitivity of the synchrotron-based Nano-IR measurements

Expected long term effects

Studies were done on tape coated steel surfaces exposed under various conditions such as accelerated aging in UV light and moisture or field exposure. Nano FTIR spectroscopy was performed on surfaces and cross sections. When relatively low signal to noise ratios were obtained with synchrotron Nano-IR measurements, the chemical information about the degradation was limited. However, information on degradation could be obtained through chemical imaging with Nano IR and O-PTIR cross-section. Further studies with laboratory-based instruments with laser sources are planned

Approach and implementation

Coil coated steel surfaces exposed to accelerated aging in UV light and moisture and field exposure at Bohus-Malmön were provided by SSAB. The paint surfaces were studied without special sample preparation, while cross-sections were prepared with broad ion beam (BIB) polishing. Nano FTIR spectroscopy was performed with scattering scanning near field optical microscopy, sSNOM connected to the SMIS 1 beamline of the synchrotron Soleil (Paris). Chemical imaging was done with the Nano-FTIR equipped with a QCL laser and with complementary measurements with O-PTIR (Optical Photothermal IR).