A characteristic property of unfolded and disordered proteins is their high molecular flexibility, which enables the exploration of a large conformational space. We present neutron scattering experiments on the dynamics of denatured and native folded bovine serum albumin (BSA) in solution. Global protein diffusion and internal macromolecular dynamics were measured using quasielastic neutron time-of-flight and backscattering spectroscopy on the picosecond to nanosecond time- and Ångstrom length-scale. Internal protein dynamics were analysed in a first approach using stretched exponential functions. In denatured BSA predominantly slow heterogeneous dynamics dominates the observed macromolecular motions. Reduction of disulphide bridges in denatured BSA does not significantly alter the visible motions. In native folded BSA fast homogeneous dynamics and slow heterogeneous dynamics were observed. In an alternative data analysis approach, internal protein dynamics was interpreted using the analytical model of the overdamped Brownian oscillator, which allowed us to extract mean square displacements of protein internal dynamics and the fraction of hydrogen atoms participating in the observed motions. Our results demonstrate that denaturation modifies the physical nature of internal protein dynamics significantly as compared to the native folded structure.

The impact of purely intramolecular cross-linking on the properties of a polymer melt is studied by neutron diffraction and quasielastic incoherent and coherent neutron scattering on a system composed exclusively of single-chain nanoparticles. As a reference, a parallel study is presented on the melt of the linear precursor chains' counterpart. Associated with structural heterogeneities provoked by the internal compartmentalization due to cross-links, a dramatic slowing down of the relaxation of density fluctuations is observed at intermediate length scales.

SPHERES (SPectrometer for High Energy RESolution), operated by JCNS, Forschungszentrum Jülich, is a third-generation neutron backscattering spectrometer with focussing optics and a phase-space-transform chopper. It enables the investigation of atomic and molecular dynamics with an energy resolution of about 0.65 µeV in a dynamic range of ± 31 µeV.

The present study focuses on structural and dynamical properties of the catalytic layer for high‐temperature polymer electrolyte fuel cells (HT‐PEFC). The catalytic layer is a composite material containing nanoporous carbon, poly(tetrafluoroethylene) (PTFE) and platinum (Pt) nanoparticles. The structure of the catalyst is investigated using small angle X‐ray scattering (SAXS) following different preparation steps of the electrodes: pure carbon support, platinum/carbon (Pt/C) powder and finally, complete catalytic layer. The structural properties of the Pt/C powder containing different amounts of Pt are discussed along with the size distribution of Pt particles and their arrangement on the surface of the carbon support. Following the preparation sequence of the catalytic layer based on the Pt/C powders the electrodes with different final Pt loadings are analyzed in details. Investigation of the structure of the catalytic layer is accompanied by the study of nanosecond dynamics of the phosphoric acid (PA) in the catalytic layer containing different amount of Pt by means of neutron backscattering spectroscopy. The structure of the catalytic layer is mostly determined by the structure of the catalytic powder and does not vary significantly with Pt loading in the electrode. The behavior of the PA is sensitive to the Pt content in the electrode.

We present experimental and theoretical studies on the infiltration of polymers (polystyrene (PS), polymethylmethacrylate (PMMA)) into the free interstices of 3D aligned carbon nanotube arrays. The 3D aligned CNT structures were prepared by a template assisted non catalytic CVD approach. The infiltrated CNT/polymer composites were characterized by microscopic techniques such as infra-red and Raman spectroscopy. Small angle X-ray scattering (SAXS) has been employed to study the structural evolution and polymer confinement after the polymers are infiltrated in the aligned arrays of CNTs. A theoretical model has been used to understand and predict possible confinement effects of these polymers within the aligned CNT arrays, using self-consistent field theory (SCFT) and Monte-Carlo simulations based on the bond-fluctuation model.

We analyze the polymer filling mechanism in composites containing highly ordered and vertically aligned carbon nanotube (CNT) arrays. CNTs are obtained by a template assisted chemical vapor deposition (CVD) method. Different forms of the arrays are studied with one or two carbon layers on top and bottom surface of the array, or freestanding CNTs. Investigation is done by small-angle X-ray scattering (SAXS) in combination with electron microscopy (TEM and SEM) and atomic force microscopy. Tubes are of 40 μm length and 40/90 nm diameter. The original order of the template is only locally preserved in the CNT array. Imbibition of polymer is achieved in the inside of CNTs as well as in between. It modifies the local order of the tubes. We compare structural changes of CNT arrays caused by polymer infiltration. Filling kinetics is followed with time-resolved SAXS. We find two well separated processes that are related to the formation of a precursor film and subsequent partial completion of the imbibition process.

The structural properties and proton transport processes of High Temperature Polymer Electrolyte Fuel Cells (HT-PEFCs) are studied on a broad range of length- and timescales with different neutron scattering techniques. We show structural properties of the proton conducting membrane and of the catalyst layer. Proton transport is measured with quasielastic neutron scattering techniques. The sensitivity of neutrons to individual isotopes, especially in the case of hydrogen and deuterium, makes neutron scattering a perfect tool for such studies. Complementary techniques such as transmission electron microscopy, PFG-NMR and X-ray scattering round up the picture of the different fuel cell components.

The nanostructure of the electrode layer of a HT-PEFC is studied with neutron and X-ray small-angle scattering techniques. The different contrasts of the two probes provide a view on different aspects of the electrode layer. In combination with contrast variation by H-D isotope exchange further insight into the distribution of the different components on length scales in the range of 1-100 nm is obtained. An outlook shows the perspectives of scattering techniques for studying proton diffusion in such heterogeneous materials.