Kinetics of nanoparticle reassembly mediated by UV-photolysis of surfactant.

Real-time reassembly of an ordered nanoparticle monolayer due to UV-photolysis of the surfactant shell of nanoparticles was observed. The technique of grazing-incidence small-angle X-ray scattering provided the possibility to track in situ the nanoparticle pair correlation function of the sample processed in a UV-ozone reactor. The analysis revealed a total shift of approximately 1 nm of the nanoparticle nearest-neighbor distance.

Adsorption in periodically ordered mesoporous organosilica materials studied by in situ small-angle X-ray scattering and small-angle neutron scattering.

Modified periodically ordered mesoporous organosilica materials were prepared starting from a recently introduced type of sol-gel precursor, containing both organic moieties and hydrolyzable Si-OR groups. In order to thoroughly characterize the mesoporosity and its accessibility, different probe gases were used in conventional gas adsorption experiments. Furthermore, in situ small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) were applied to study the mesoporosity and the sorption processes, taking advantage of scattering contrast matching conditions.

Analysis of microporosity in ordered mesoporous hierarchically structured silica by combining physisorption with in situ small-angle scattering (SAXS and SANS).

The combination of physisorption experiments with simultaneous in situ small-angle X-ray and neutron scattering (SAXS/SANS) was used to elucidate the porosity in mesoporous silica with a trimodal pore structure. The material ("KLE-IL") contains spherical mesopores of 14 nm in diameter, worm-like mesopores (2-3 nm), and micropores, templated by a block copolymer and an ionic liquid surfactant, while the micropores originate from the hydrophilic block of the block copolymer. The main objective of the study was the quantification of the microporosity and the small mesopores and to find out if they are indeed located between the larger, spherical mesopores.

Grazing incidence small-angle X-ray scattering microtomography demonstrated on a self-ordered dried drop of nanoparticles.

We combine grazing-incidence small-angle X-ray scattering (GISAXS) with scanning X-ray microtomography to investigate the nanostructure in a dried gold/polystyrene nanocomposite drop. Local GISAXS structure factors are reconstructed at each position on the surface of this two-dimensionally heterogeneous sample with 30 microm pixel size. Evidence for four types of self-assembled colloidal crystalline structures is provided by the reconstructed data of the drop demonstrating the feasibility of the method.

Small angle x-ray scattering with a beryllium compound refractive lens as focusing optic.

At BW4 at HASYLAB a beryllium compound refractive lens (Be-CRL) is used for the focusing in small-angle x-ray scattering experiments. Using it provides the advantages of higher long-term stability and a much easier alignment compared to a setup with focusing mirrors. In our investigations presented here, we show the advantages of using a Be-CRL in small-angle and also ultra small-angle x-ray scattering.

Preservation of the morphology of a self-encapsulated thin titania film in a functional multilayer stack: an X-ray scattering study.

Tailoring of the titania morphology is achieved by the combination of a triblock copolymer, acting as structure-directing agent, and a sol-gel chemistry enabling the incorporation of the provided inorganic material (titania) into the selected phase of the triblock copolymer. Spin-coating of the solution on FTO-coated glass, followed by plasma etching and calcination of the thin film results in the formation of self-encapsulated crystalline titania nanostructures. The fabricated nanostructures are coated stepwise with dye, conductive polymers and gold forming a functional multilayer stack.

Structures of regenerated cellulose films revealed by grazing incidence small-angle x-ray scattering.

The characteristic in-plane length scales of ultrathin films of regenerated cellulose are measured using noncontact atomic force microscopy (NC-AFM) and grazing incidence small-angle x-ray scattering (GISAXS) in ambient atmosphere and under various humidity conditions. The aim is to elucidate the structural basis for the excellent compatibility of cellulose supports to planar lipid membranes. Films are deposited on silicon wafers by Langmuir-Blodgett (LB) transfer and spin coating.

Order causes secondary Bragg peaks in soft materials.

Highly ordered soft materials exhibit Bragg peaks that cannot be indexed assuming homogeneous crystal structures. Their origin has been attributed to changes in the crystal structure that are induced by the ordering process such as by application of external fields. This would restrict the use for the generation of highly ordered nano- and microstructured materials where a homogeneous crystal structure is a key requirement.