Electron microscopy investigations of hierarchical porous nanostructures for energy and healthcare applications

The Chemistry team (Howdle) in close collaboration with the Adolphe Merkel Institute in Fribourg, is developing new methodologies to make hierarchical nanostructured polymeric materials with control on both the micro- and nano-length scales and these wil be carefully evaluated and imaged in collaboration with the Engineering and Microscopy team (Brown). The way ahead is to exploit new discoveries in dispersion polymerisation in supercritical carbon dioxide (scCO2), to establish practical routes towards materials for more efficient devices such as battery anodes, along with solar cells, electrodes, photonic crystals and high density optical/magnetic storage. The present aim is to understand precisely how the combined effects of polymer chemistry and self-assembly in scCO2 impact upon the nanostructured polymers before they are translated into inorganic (e.g. TiO2 or SiO2) structures by a templating process, to yield the hierarchical porous nanostructures desired for application (Howdle/Chemistry). In this context, materials characterisation using electron microscopy provides for precise descriptions of sample morphologies. The challenge in this case is to stabilise these thermally sensitive materials for imaging under the high energy electron beam. Accordingly, a number of different sample handling and imaging protocols will be investigated, including cryo-ultramicrotomy, environmental scanning electron microscopy (ESEM) and transmission electron microscopy (TEM), as compared with the applicability of site-specific sectioning using cryogenic focused ion beam scanning electron microscopy (CryoFIBSEM), in order to examine the influence of process parameters on porous nanostructure development (Brown/Engineering).