Small angle X-ray scattering was used to study the morphology of conical structures formed in thin films of amorphous SiO 2. Samples were irradiated with 1.1 GeV Au ions at the GSI UNILAC in Darmstadt, Germany, and with 185, 89 and 54 MeV Au ions at the Heavy Ion Accelerator Facility at ANU in Canberra, Australia. The irradiated material was subsequently etched in HF using two different etchant concentrations over a series of etch times to reveal conically shaped etched channels of various sizes. Synchrotron based SAXS measurements were used to characterise both the radial and axial ion track etch rates with unprecedented precision. The results show that the ion energy has a significant effect on the morphology of the etched channels, and that at short etch times resulting in very small cones, the increased etching rate of the damaged region in the radial direction with respect to the ion trajectory is significant.

No abstract

Small-angle x-ray scattering (SAXS) was used to quantitatively study the morphology of aligned, monodisperse conical etched ion tracks in thin films of amorphous SiO 2 with aspect ratios of around 6 : 1 and in polycarbonate foils with aspect ratios of around 1000 : 1. This paper presents the measurement procedure and methods developed for the analysis of the scattering images and shows results obtained for the two material systems. To enable accurate parameter extraction from the data collected from conical scattering objects, a model fitting the two-dimensional (2D) detector images was developed. The analysis involved fitting images from a sequence of measurements with different sample tilts to minimize errors, which may have been introduced due to the experimental setup. The model was validated by the exploitation of the geometric relationship between the sample tilt angle and the cone opening angle, to an angle observed in the features of the SAXS images. We also demonstrate that a fitting procedure for 1D data extracted from the scattering images using a hard cylinder model can also be used to extract the cone size. The application of these techniques enables us to reconstruct the cone morphologies with unprecedented precision.

Nanoscale structuring in confined geometries using atomic layer deposition (ALD) is demonstrated for surfaces of nanochannels in track-etched polymer membranes and in mesoporous silica (SBA-15). Suitable process conditions for conformal ALD coating of polymer membranes and SBA-15 with inorganic oxides (SiO2, TiO2, Al2O3) were developed. On the basis of the oxide-coated layers, nanochannels were further structured by a molecular-templated ALD approach, where calixarene macromolecules are covalently attached to the surface and then embedded into an Al2O3 layer. The removal of calixarene by ozone treatment results in 1–2 nm wide surface nanocavities. Surfaces exposed to different process steps are analyzed by small angle X-ray scattering (SAXS) as well as by X-ray photoelectron and infrared spectroscopy. The proposed nanostructuring process increases the overall surface area, allows controlling the hydrophilicity of the channel surface, and is of interest for studying water and ion transport in confinement.

No abstract