Correlations between microstructure and crystallization of the fluorinated terpolymer of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride

Ok, Salim; Hartmann, Brigitte; Duran, Hatïce; Eickmeier, Henning; Haase, Markus; Scheler, Ulrich; Steinhart, Martin

doi:10.1002/polb.24886

Cited by 5 publications

(2 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The macromolecular structure and thermal properties of the polymer have already been characterized. [13,14] Accordingly, the polymer has a chemical composition of 43.8 mol% tetrafluoroethylene (TFE), 46.0 mol% vinylidene fluoride (VDF), and 10.2 mol% hexafluoropropylene (HFP), a molecular weight of 4100 g mol −1 , and a broad melting temperature range between 365 and 400 K. The spinning solution was filled into a glass syringe (1.0 mL, Gastight 1000 Series, Hamilton Company), which was connected via LDPE tubing (0.38 mm I.D., 1.09 mm O.D., Science Commodities Inc.) to the microfluidic nozzle device. Precise pumping of the spinning solution at constant flow rates between 0.5 and 4.0 mL h −1 was ensured by using a syringe pump (neMESYS 290N, Cetoni GmbH).…”

Section: Microfluidic Solution Blow Spinning and Sample Collectionmentioning

confidence: 99%

Controlling Polymer Microfiber Structure by Micro Solution Blow Spinning

Hofmann

Dulle

Liao

et al. 2019

Macro Chemistry & Physics

View full text Add to dashboard Cite

In the device, the polymer spinning dope solution is surrounded by a high-velocity air flow and thereby focused into a thin liquid jet. After the evaporation of the solvent, the resulting fiber can either be spooled or collected as a non-woven fabric. [1] The produced nanofiber mats and scaffolds are of great interest for biomedical applications like drug delivery and tissue engineering, [4-6] with the possibility of direct application onto wounds or tissues. [1,7] Previous investigations on SBS have focused on empirical and qualitative relationships between specific process parameters (gas pressure, flow rate), solution parameters (solvent, polymer solution concentration, molecular weight), and fiber diameter. [1,3,8-11] In a more detailed study, X-ray diffraction was employed to determine crystallinity, d-spacing, and crystallite size of SBS-produced fibers in comparison to electrospun fibers and casted films. [7] However, a complete and quantitative relation between the main blow spinning parameters and the structure of the resulting fiber is still lacking. In this study, we use a lithographically produced micro fluidic nozzle device to produce fibers at controlled spinning conditions. The design of the microfluidic device was introduced recently. [12] It allows controlling the velocity and diameter of the exiting liquid jet with high precision. Here we demonstrate using continuous microfluidic solution blow spinning (µSBS) together with small-and wide-angle X-ray scattering (SAXS, WAXS) that this microfluidic device enables unique quantitative control of the spinning conditions to suitably tailor the microfiber diameter and its internal macromolecular alignment. It thus has great implications for a quantitatively controlled production of microfibers using highly miniaturized spinning devices. 2. Experimental Section 2.1. Fabrication of Microfluidic Devices The nozzle devices for µSBS were produced using standard photolithography and soft lithography techniques. The complete procedure was described in detail in a previous publication. [12] By using photolithography, a microstructured master was produced and afterward casted with poly(dimethylsiloxane) (PDMS; Sylgard 184 kit, Dow Corning Corp.). Two individually Recent progress in microfluidic technology allows fabricating microfluidic devices to produce liquid microjets with unprecedented control of the jet diameter and velocity. Here it is demonstrated that microfluidic devices based on the gas dynamic virtual nozzle principle can be excellently used for micro solution blow spinning to continuously fabricate microfibers with excellent control of the fiber diameter and the internal crystalline alignment that determines the mechanical properties. Fiber spinning experiments with small-and wide-angle X-ray scattering are combined to directly relate the macroscopic spinning conditions to the bulk and molecular structure of the resulting fibers. The elongational rate is shown as the relevant parameter that transduces the nozzle flow conditions to the local macromol...

show abstract