@article{BoehmTandonHrynevichetal.2022,
  author    = {B{\"o}hm, Christoph and Tandon, Biranche and Hrynevich, Andrei and Teßmar, J{\"o}rg and Dalton, Paul D.},
  title     = {Processing of Poly(lactic-co-glycolic acid) Microfibers via Melt Electrowriting},
  series = {Macromolecular Chemistry and Physics},
  volume    = {223},
  journal   = {Macromolecular Chemistry and Physics},
  number    = {5},
  doi       = {10.1002/macp.202100417},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-318444},
  year      = {2022},
  abstract  = {Polymers sensitive to thermal degradation include poly(lactic-co-glycolic acid) (PLGA), which is not yet processed via melt electrowriting (MEW). After an initial period of instability where mean fiber diameters increase from 20.56 to 27.37 µm in 3.5 h, processing stabilizes through to 24 h. The jet speed, determined using critical translation speed measurements, also reduces slightly in this 3.5 h period from 500 to 433 mm min\(^{-1}\) but generally remains constant. Acetyl triethyl citrate (ATEC) as an additive decreases the glass transition temperature of PLGA from 49 to 4 °C, and the printed ATEC/PLGA fibers exhibits elastomeric behavior upon handling. Fiber bundles tested in cyclic mechanical testing display increased elasticity with increasing ATEC concentration. The processing temperature of PLGA also reduces from 165 to 143 °C with increase in ATEC concentration. This initial window of unstable direct writing seen with neat PLGA can also be impacted through the addition of 10-wt\% ATEC, producing fiber diameters of 14.13 ± 1.69 µm for the first 3.5 h of heating. The investigation shows that the initial changes to the PLGA direct-writing outcomes seen in the first 3.5 h are temporary and that longer times result in a more stable MEW process.},
  language  = {en}
}
@article{BakirciFrankGumbeletal.2021,
  author    = {Bakirci, Ezgi and Frank, Andreas and Gumbel, Simon and Otto, Paul F. and F{\"u}rsattel, Eva and Tessmer, Ingrid and Schmidt, Hans-Werner and Dalton, Paul D.},
  title     = {Melt Electrowriting of Amphiphilic Physically Crosslinked Segmented Copolymers},
  series = {Macromolecular Chemistry and Physics},
  volume    = {222},
  journal   = {Macromolecular Chemistry and Physics},
  number    = {22},
  doi       = {10.1002/macp.202100259},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-257572},
  year      = {2021},
  abstract  = {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.},
  language  = {en}
}
@article{LiashenkoHrynevichDalton2020,
  author    = {Liashenko, Ievgenii and Hrynevich, Andrei and Dalton, Paul D.},
  title     = {Designing Outside the Box: Unlocking the Geometric Freedom of Melt Electrowriting using Microscale Layer Shifting},
  series = {Advanced Materials},
  volume    = {32},
  journal   = {Advanced Materials},
  number    = {28},
  doi       = {10.1002/adma.202001874},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-217974},
  year      = {2020},
  abstract  = {Melt electrowriting, a high-resolution additive manufacturing technology, has so far been developed with vertical stacking of fiber layers, with a printing trajectory that is constant for each layer. In this work, microscale layer shifting is introduced through deliberately offsetting the printing trajectory for each printed layer. Inaccuracies during the printing of sinusoidal walls are corrected via layer shifting, resulting in accurate control of their geometry and mechanical properties. Furthermore, more substantial layer shifting allows stacking of fiber layers in a horizontal manner, overcoming the electrostatic autofocusing effect that favors vertical layer stacking. Novel nonlinear geometries, such as overhangs, wall texturing and branching, and smooth and abrupt changes in printing trajectory are presented, demonstrating the flexibility of the layer shifting approach beyond the state-of-the-art. The practice of microscale layer shifting for melt electrowriting enables more complex geometries that promise to have a profound impact on the development of products in a broad range of applications.},
  language  = {en}
}