TY  - JOUR
A1  - Mechau, Jannik
A1  - Frank, Andreas
A1  - Bakirci, Ezgi
A1  - Gumbel, Simon
A1  - Jungst, Tomasz
A1  - Giesa, Reiner
A1  - Groll, Jürgen
A1  - Dalton, Paul D.
A1  - Schmidt, Hans‐Werner
T1  - Hydrophilic (AB)\(_{n}\) Segmented Copolymers for Melt Extrusion‐Based Additive Manufacturing
JF  - Macromolecular Chemistry and Physics
N2  - Several manufacturing technologies beneficially involve processing from the melt, including extrusion‐based printing, electrospinning, and electrohydrodynamic jetting. In this study, (AB)\(_{n}\) segmented copolymers are tailored for melt‐processing to form physically crosslinked hydrogels after swelling. The copolymers are composed of hydrophilic poly(ethylene glycol)‐based segments and hydrophobic bisurea segments, which form physical crosslinks via hydrogen bonds. The degree of polymerization was adjusted to match the melt viscosity to the different melt‐processing techniques. Using extrusion‐based printing, a width of approximately 260 µm is printed into 3D constructs, with excellent interlayer bonding at fiber junctions, due to hydrogen bonding between the layers. For melt electrospinning, much thinner fibers in the range of about 1–15 µm are obtained and produced in a typical nonwoven morphology. With melt electrowriting, fibers are deposited in a controlled way to well‐defined 3D constructs. In this case, multiple fiber layers fuse together enabling constructs with line width in the range of 70 to 160 µm. If exposed to water the printed constructs swell and form physically crosslinked hydrogels that slowly disintegrate, which is a feature for soluble inks within biofabrication strategies. In this context, cytotoxicity tests confirm the viability of cells and thus demonstrating biocompatibility of this class of copolymers.
KW  - 3D printing
KW  - (AB)\(_{n}\) segmented copolymers
KW  - biocompatibility
KW  - melt electrowriting
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-224513
VL  - 222
IS  - 1
ER  - 
TY  - JOUR
A1  - Hochleitner, Gernot
A1  - Jüngst, Tomasz
A1  - Brown, Toby D
A1  - Hahn, Kathrin
A1  - Moseke, Claus
A1  - Jakob, Franz
A1  - Dalton, Paul D
A1  - Groll, Jürgen
T1  - Additive manufacturing of scaffolds with sub-micron filaments via melt electrospinning writing
JF  - Biofabrication
N2  - The aim of this study was to explore the lower resolution limits of an electrohydrodynamic process combined with direct writing technology of polymer melts. Termed melt electrospinning writing, filaments are deposited layer-by-layer to produce discrete three-dimensional scaffolds for in vitro research. Through optimization of the parameters (flow rate, spinneret diameter, voltage, collector distance) for poly-ϵ-caprolactone, we could direct-write coherent scaffolds with ultrafine filaments, the smallest being 817 ± 165 nm. These low diameter filaments were deposited to form box-structures with a periodicity of 100.6 ± 5.1 μm and a height of 80 μm (50 stacked filaments; 100 overlap at intersections). We also observed oriented crystalline regions within such ultrafine filaments after annealing at 55 °C. The scaffolds were printed upon NCO-sP(EO-stat-PO)-coated glass slide surfaces and withstood frequent liquid exchanges with negligible scaffold detachment for at least 10 days in vitro.
KW  - additive manufacturing
KW  - 3D printing
KW  - biodegradable polymers
KW  - microstructures
KW  - nanostructures
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-254053
VL  - 7
IS  - 3
ER  -