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  - 
TY  - JOUR
A1  - Kade, Juliane C.
A1  - Otto, Paul F.
A1  - Luxenhofer, Robert
A1  - Dalton, Paul D.
T1  - Melt electrowriting of poly(vinylidene difluoride) using a heated collector
JF  - Polymers for Advanced Technologies
N2  - 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.
KW  - additive manufacturing
KW  - polymer processing
KW  - melt electrowriting
KW  - electroactive
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318493
SN  - 1042-7147
VL  - 32
IS  - 12
SP  - 4951
EP  - 4955
ER  - 
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  -