A quantitative approach to tune metal oxide network morphology based on grazing-incidence small-angle X-ray scattering investigations

Based on a diblock copolymer-assisted sol-gel route, zinc oxide (ZnO) films with a foam-like network morphology are synthesized using zinc acetate dihydrate as a precursor. Poly(styrene-block-ethylene oxide) diblock copolymers with two different molecular weights are examined to compare the influence on the resulting morphologies. The variation in the porosity and in the pore size of the ZnO foam as a function of increasing amount of ZnO precursor are probed with grazing-incidence small-angle X-ray scattering (GISAXS). The GISAXS data are complemented with a surface topography investigation based on scanning electron microscopy. It is observed that the block copolymer template with the higher molecular weight yields a smaller average pore size and a lower average porosity of about 21%.