Andreas Morschhauser

Microfluidic setup for on-line SERS monitoring using laser induced nanoparticle spots as SERS active substrate

A microfluidic setup which enables on-line monitoring of residues of malachite green (MG) using surface-enhanced Raman scattering (SERS) is reported. The SERS active substrate was prepared via laser induced synthesis of silver or gold nanoparticles spot on the bottom of a 200 μm inner dimension glass capillary, by focusing the laser beam during a continuous flow of a mixture of silver nitrate or gold chloride and sodium citrate. The described microfluidic setup enables within a few minutes the monitoring of several processes: the synthesis of the SERS active spot, MG adsorption to the metal surface, detection of the analyte when saturation of the SERS signal is reached, and finally, the desorption of MG from the spot. Moreover, after MG complete desorption, the regeneration of the SERS active spot was achieved. The detection of MG was possible down to 10−7 M concentration with a good reproducibility when using silver or gold spots as SERS substrate.

Ferroelectric P(VDF-TrFE) as a large-scale piezoelectric sensor in a table-tennis racquet

Piezoelectric poly(vinylidene fluoride — trifluoroethylene) copolymer is embedded as a functional material in a table-tennis racquet. Together with the developed electronics, this piezoelectric sensor is able to monitor the position where the ball contacts the racquet. In order to build up the device, conventional circuit boards with adapted electrode structures are used as substrates for the piezoelectric table-tennis racquet. This leads to challenges because such substrates are usually not flat in the micrometer range as well as the heights of copper electrodes cause irregularities in the final surface topology. Here, the adaptation of the circuit boards, the processing and polarization of the piezoelectric polymer layer, the designed electronics for signal detection and the properties of the table tennis racquet are discussed.