3D printing via fused deposition modeling (FDM) has developed to the probably most common rapid prototyping technology due to its easy of use and broad range of available materials. Nowadays, FDM printed parts are on the way to be used in various applications ranging from all-day use to more technical purposes. As a matter of fact, the mechanical strength is one of the main parameters to be optimized by the choice of the material and the 3D-printing settings, such as layer height, nozzle temperature and printing speed. Here, we report on the improvement of the mechanical properties of printed parts by use of an inert gas atmosphere during the print. A typical FDM printer has been inserted into the nitrogen atmosphere of a glove box and used without modifications to print parts made of acrylonitrile butadiene styrene and polyamide as printing materials with a high mechanical load tolerance. Probably partly due to the prevention of oxidation processes, a significant increase in elongation at break and tensile strength was observed. This may be explained by a reduced degradation of the polymer surface at the comparatively high printing temperature. 3D printing under the exclusion of oxygen may be realized comparatively easy by flooding the printing chamber with nitrogen in future applications for the production of FDM-printed parts with improved mechanical properties.

Changes in the viscoe-lasticity of the electric double layer following steps in electrode potential were studied with an electrochemical quartz crystal microbalance (EQCM). The overtone scaling was the same as...

A set of push–pull substituted arylnaphthylalkynes has been synthesized under inert gas conditions in 3D-printed cuvettes out of NMR-transparent polyamide and their optical properties were investigated.

The operation of the quartz crystal microbalance (QCM) in liquids is plagued by small flexural admixtures to the thickness-shear deformation. The resonator surface moves not only in the transverse direction, but also along the surface normal, thereby emitting compressional waves into the liquid. Using a simple analytical model and laser Doppler vibrometry, we show that the flexural admixtures are stronger on the fundamental mode than on the overtones. The normal amplitude of motion amounts to about 1% of the transverse motion on the fundamental mode. This ratio drops by a factor of two on the overtones. A similar dependence on overtone order is observed in experiments, where the resonator is immersed in a liquid and faces an opposite planar wall, the distance of which varies. Standing compressional waves occur at certain distances. The amplitudes of these are smaller on the overtones than on the fundamental mode. The findings can be rationalized with the tensor form of the small-load approximation.

Quartz crystal microbalance with dissipation monitoring (QCMD) is a simple and versatile sensing technique with applications in a wide variety of academic and industrial fields, most notably electrochemistry, biophysics, quality control, and environmental monitoring. QCMD is limited by a relatively poor time resolution, which is of the order of seconds with conventional instrument designs at the noise level usually required. In this work, we present a design of an ultrafast QCMD with submillisecond time resolution. It is based on a frequency comb approach applied to a high-fundamental-frequency (HFF) resonator through a multifrequency lock-in amplifier. The combination allows us to reach data acquisition rates >10 kHz. We illustrate the method using a toy model of a glass sphere dropped on the resonator surfaces, bare or coated with liposomes, in liquid. We discuss some interesting features of the results obtained with the dropped spheres, such as bending of the HFF resonators due to the impact, sphere bouncing (or the absence of it), and contact aging.