Previous research on the melt electrowriting (MEW) of poly(vinylidene difluoride) (PVDF) resulted in electroactive fibers, however, printing more than five layers is challenging. Here, we investigate the influence of a heated collector to adjust the solidification rate of the PVDF jet so that it adheres sufficiently to each layer. A collector temperature of 110 C is required to improve fiber processing, resulting in a total of 20 fiber layers. For higher temperatures and higher layers, an interesting phenomenon occurred, where the intersection points of the fibers coalesced into periodic spheres of diameter 206 ± 52 μm (26G, 150 C collector temperature, 2000 mm/min, 10 layers in x-and y-direction).The heated collector is an important component of a MEW printer that allows polymers with a high melting point to be processable with increased layers.

Various (AB)n and (ABAC)n segmented copolymers with hydrophilic and hydrophobic segments are processed via melt electrowriting (MEW). Two different (AB)n segmented copolymers composed of bisurea segments and hydrophobic poly(dimethyl siloxane) (PDMS) or hydrophilic poly(propylene oxide)‐poly(ethylene oxide)‐poly(propylene oxide) (PPO‐PEG‐PPO) segments, while the amphiphilic (ABAC)n segmented copolymers consist of bisurea segments in the combination of hydrophobic PDMS segments and hydrophilic PPO‐PEG‐PPO segments with different ratios, are explored. All copolymer compositions are processed using the same conditions, including nozzle temperature, applied voltage, and collector distance, while changes in applied pressure and collector speed altered the fiber diameter in the range of 7 and 60 µm. All copolymers showed excellent processability with MEW, well‐controlled fiber stacking, and inter‐layer bonding. Notably, the surfaces of all four copolymer fibers are very smooth when visualized using scanning electron microscopy. However, the fibers show different roughness demonstrated with atomic force microscopy. The non‐cytotoxic copolymers increased L929 fibroblast attachment with increasing PDMS content while the different copolymer compositions result in a spectrum of physical properties.

Present surgical situations require a bone adhesive which has not yet been developed for use in clinical applications. Recently, phosphoserine modified cements (PMC) based on mixtures of o-phosphoserine (OPLS) and calcium phosphates, such as tetracalcium phosphate (TTCP) or α-tricalcium phosphate (α-TCP) as well as chelate setting magnesium phosphate cements have gained increasing popularity for their use as mineral bone adhesives. Here, we investigated new mineral-organic bone cements based on phosphoserine and magnesium phosphates or oxides, which possess excellent adhesive properties. These were analyzed by X-ray diffraction, Fourier infrared spectroscopy and electron microscopy and subjected to mechanical tests to determine the bond strength to bone after ageing at physiological conditions. The novel biomineral adhesives demonstrate excellent bond strength to bone with approximately 6.6–7.3 MPa under shear load. The adhesives are also promising due to their cohesive failure pattern and ductile character. In this context, the new adhesive cements are superior to currently prevailing bone adhesives. Future efforts on bone adhesives made from phosphoserine and Mg2+ appear to be very worthwhile. Graphical Abstract