TY  - JOUR
A1  - Kade, Juliane C.
A1  - Bakirci, Ezgi
A1  - Tandon, Biranche
A1  - Gorgol, Danila
A1  - Mrlik, Miroslav
A1  - Luxenhofer, Robert
A1  - Dalton, Paul D.
T1  - The Impact of Including Carbonyl Iron Particles on the Melt Electrowriting Process
JF  - Macromolecular Materials and Engineering
N2  - Melt electrowriting, a high-resolution additive manufacturing technique, is used in this study to process a magnetic polymer-based blend for the first time. Carbonyl iron (CI) particles homogenously distribute into poly(vinylidene fluoride) (PVDF) melts to result in well-defined, highly porous structures or scaffolds comprised of fibers ranging from 30 to 50 µm in diameter. This study observes that CI particle incorporation is possible up to 30 wt% without nozzle clogging, albeit that the highest concentration results in heterogeneous fiber morphologies. In contrast, the direct writing of homogeneous PVDF fibers with up to 15 wt% CI is possible. The fibers can be readily displaced using magnets at concentrations of 1 wt% and above. Combined with good viability of L929 CC1 cells using Live/Dead imaging on scaffolds for all CI concentrations indicates that these formulations have potential for the usage in stimuli-responsive applications such as 4D printing.
KW  - additive manufacturing
KW  - melt electrospinning writing
KW  - magnetoactive materials
KW  - electroactive polymers
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318482
SN  - 1438-7492
VL  - 307
IS  - 12
ER  - 
TY  - JOUR
A1  - Böhm, Christoph
A1  - Tandon, Biranche
A1  - Hrynevich, Andrei
A1  - Teßmar, Jörg
A1  - Dalton, Paul D.
T1  - Processing of Poly(lactic–co–glycolic acid) Microfibers via Melt Electrowriting
JF  - Macromolecular Chemistry and Physics
N2  - 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.
KW  - poly(lactide-co-glycolide)
KW  - 3D printing
KW  - additive manufacturing
KW  - electrohydrodynamics
KW  - melt electrospinning writing
KW  - plasticizers
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318444
VL  - 223
IS  - 5
ER  - 
TY  - JOUR
A1  - Kade, Juliane C.
A1  - Tandon, Biranche
A1  - Weichhold, Jan
A1  - Pisignano, Dario
A1  - Persano, Luana
A1  - Luxenhofer, Robert
A1  - Dalton, Paul D.
T1  - Melt electrowriting of poly(vinylidene fluoride‐co‐trifluoroethylene)
JF  - Polymer International
N2  - Poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-co-TrFE)) is an electroactive polymer with growing interest for applications in biomedical materials and flexible electronics. In this study, a solvent-free additive manufacturing technique called melt electrowriting (MEW) has been utilized to fabricate well-defined microperiodic structures of the copolymer (P(VDF-co-TrFE)). MEW of the highly viscous polymer melt was initiated using a heated collector at temperatures above 120 °C and required remarkably slow collector speeds below 100 mm min\(^{-1}\). The fiber surface morphology was affected by the collector speed and an increase in β-phase was observed for scaffolds compared to the unprocessed powder. Videography shows vibrations of the P(VDF-co-TrFE) jet previously unseen during MEW, probably due to repeated charge buildup and discharge. Furthermore, piezo-force microscopy measurements demonstrated the electromechanical response of MEW-fabricated fibers. This research therefore achieves the melt electrohydrodynamic processing of fibers with micrometer resolution into defined structures with an important electroactive polymer.
KW  - polymer processing
KW  - additive manufacturing
KW  - electrohydrodynamic
KW  - electroactive
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-257654
VL  - 70
IS  - 12
ER  -