466016 Gravimetric Analysis Under Process-Near Conditions at Nanogramme Resolution: New Sorption and Solvation Apparatus for Very Small Sample Quantities
A new apparatus has been developed within the RESOLV cluster of excellence (funded by the German Research Foundation) which takes advantage of the new NMSB, regarding the higher resolution as well as the free choice of measuring configuration. To realize this, a flexible interface has been devised to permit conversion of the same balance between a top and bottom loading configuration, depending on the measurement to be performed. The top loading configuration is particularly advantageous for thermogravimetric analysis with elevated temperatures, as the high temperature low density area is situated above the NMSB itself which is in the low temperature, high density area of the pressure cell. This configuration is used for thermogravimetric analysis and adsorption quantification on small sample quantities of porous materials; here we have obtained high quality results of N2 and CO2 adsorption on metal organic framework materials with sample quantities in the range of 5 mg (many 100s of factors smaller than i.e. volumetric methods). The bottom loading configuration is somewhat simplified and is used for experiments with high dead weights but which require the high resolution of the new NMSB. Here we are investigating weight changes in moistening and drying processes on two dimensional model surfaces simulating new coatings against biofouling . These samples combine high weight (of the wafer substrate) with very low specific surface area, resulting in a small measurable weight difference. The flexible new apparatus is connected to a gas dosing system comprising a component for static dosing of dry gases and a component for dosing binary gas mixtures under flow conditions mixed with saturated vapours. Results of these dynamic mixture measurements will also be presented.
 H. W. Lösch, PhD Thesis, Ruhr-University Bochum (1987)
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