Eindimensionale Ramanspektroskopie zur Temperatur- und Konzentrationsmessung in Hydrogelen

  • One dimensional Raman spectroscopy as a tool for measuring temperature and concentration profiles in gel beads

Masuch, Kai; Lucas, Klaus (Thesis advisor)

Aachen : Publikationsserver der RWTH Aachen University (2011)
Dissertation / PhD Thesis

Aachen, Techn. Hochsch., Diss., 2010


Within this work a new measurement technique to determine 1D temperature and concentration profiles in gel beads with high spatial and temporal resolution is presented. In particular for inhomogeneous gels like calcium alginate such a measurement technique is essential to observe local phenomena. The method applied here is linear 1D-Raman spectroscopy in combination with indirect hard modeling (IHM), which is used for data reduction. IHM is based on parametric pure component models and therefore allows the modeling of nonlinear effects, introduced by mixture and temperature effects. An aqueous solution containing 1-butanol diffusing into a calcium alginate bead is chosen as model system. This choice is motivated by the practical usage of gel beads to immobilize catalysts for esterifications. The influence of temperature on the spectra of 1-butanol-water as well as the determined concentration is analyzed in detail. The temperature is measured by a pseudo concentration measurement. Therefore for each substance two models at two different, but known temperatures are generated. The temperature of the system is correlated to the spectral weight of these components. This approach is applied to pure water and butanol, and furthermore to aqueous solutions containing butanol, alginate or calcium chloride. The presented measurement technique is expected to be suitable for a large variety of substances as long as the system is light-transmissive for the wavelengths used for excitation and detection. The observable substances include many different hydrogels containing even multiple diffusants.


  • Chair and Institute of Technical Thermodynamics [412110]