Markus Wolkenhauer

Investigation of micromechanical cantilever sensors with microfocus grazing incidence small-angle X-ray scattering

Micromechanical cantilever arrays coated with polymer brushes are an alternative to traditional chemical sensors. A critical parameter for the sensor sensitivity is the coating quality, and small changes in the coating uniformity generate a different behavior of the sensors. Microfocus grazing incidence small-angle x-ray scattering proved to be a sensitive tool to characterize coating quality, enabling a structural and chemical coating analysis.

A Facile Route to Reassemble Titania Nanoparticles Into Ordered Chain-like Networks on Substrate

A facile route to reassemble titania nanoparticles within the titania-block copolymer composite films has been developed. The titania nanoparticles templated by the amphiphilic block copolymer of poly(styrene)-block-poly (ethylene oxide) (PS-b-PEO) were frozen in the continuous PS matrix. Upon UV exposure, the PS matrix was partially degraded, allowing the titania nanoparticles to rearrange into chain-like networks exhibiting a closer packing. The local structures of the Titania chain-like networks were investigated by both AFM and SEM; the lateral structures and vertical structures of the films were studied by GISAXS and X-ray reflectivity respectively. Both the image analysis and X-ray scattering characterization prove the reassembly of the titania nanoparticles after UV exposure. The mechanism of the nanoparticle assembly is discussed.

X-ray and neutron grazing incidence scattering study of a ternary ultra-thin polymer blend film

Abstract Structure formation in a multicomponent ultrathin polymer blend film was investigated at and below the surface with grazing incidence X‐ray and neutron scattering and scanning force microscopy (SFM). Two films were examined. First a strongly incompatible binary polymer blend film in which a buried structure was clearly identified. This binary blend film then was compared with a ternary blend film into which 5 wt% of a compatibilizing copolymer had been added. The addition of the compatibilizer was found to decrease the size of the internal structures, while leaving the surface morphology unchanged.