Structural Investigations on resorcinol-formaldehyde aerogels and carbon aerogels by means of holotomography

The visualization of the three-dimensional structure of aerogels and xerogels with sub-micrometer resolution remains a challenging task. Such information, however, would reveal the real shape and size of particles and pores within a hollow gel body and thus allow a validation (and potentially a correction) of methods such as the Barrett-Joyner-Halenda analysis for pore size distribution which are currently applied in the characterization of aerogels. This poster describes efforts to probe the structure of resorcinol-formaldehyde gels and carbonized derivatives by means of holotomography, a specific method that involves the treatment of samples with hard x-ray irradiation at different distances in order to compose the resulting two-dimensional images to a three-dimensional picture. The preparation of suitable samples, their treatment with synchrotron irradiation and the post-processing of images with a voxel size of 60 nanometers are described. Our first results show that both hard and soft organic and carbon gels are viable for holotomography and the hard synchrotron irradiation involved with that method. Furthermore, the relative order of pore sizes of hard and soft resorcinol-formaldehyde aerogels and analogous carbon gels was found to be in agreement with other characterization techniques