Partner: Arkadii Arinstein

Technion-Israel Institute of Technology (IL)

Recent publications
1.Ura D.P., Rosell-Llompart J., Zaszczyńska A., Vasilyev G., Gradys A., Szewczyk P.K., Knapczyk-Korczak J., Avrahami R., Šišková A.O., Arinstein A., Sajkiewicz P., Zussman E., Stachewicz U., The role of electrical polarity in electrospinning and on the mechanical and structural properties of as-spun fibers, Materials, ISSN: 1996-1944, DOI: 10.3390/ma13184169, Vol.13, No.18, pp.4169-1-18, 2020
Abstract:

Electric field strength and polarity in electrospinning processes and their effect on process dynamics and the physical properties of as-spun fibers is studied. Using a solution of the neutral polymer such as poly(methyl methacrylate) (PMMA) we explored the electrospun jet motion issued from a Taylor cone. We focused on the straight jet section up to the incipient stage of the bending instability and on the radius of the disk of the fibers deposited on the collecting electrode. A new correlation formula using dimensionless parameters was found, characterizing the effect of the electric field on the length of the straight jet, L˜E~E˜0.55. This correlation was found to be valid when the spinneret was either negatively or positively charged and the electrode grounded. The fiber deposition radius was found to be independent of the electric field strength and polarity. When the spinneret was negatively charged, L˜E was longer, the as-spun fibers were wider. The positively charged setup resulted in fibers with enhanced mechanical properties and higher crystallinity. This work demonstrates that often-overlooked electrical polarity and field strength parameters influence the dynamics of fiber electrospinning, which is crucial for designing polymer fiber properties and optimizing their collection.

Keywords:

fibers, electrical polarity, charges, electrospinning, PMMA, mechanical properties

Affiliations:
Ura D.P.-AGH University of Science and Technology (PL)
Rosell-Llompart J.-other affiliation
Zaszczyńska A.-IPPT PAN
Vasilyev G.-Technion-Israel Institute of Technology (IL)
Gradys A.-IPPT PAN
Szewczyk P.K.-other affiliation
Knapczyk-Korczak J.-other affiliation
Avrahami R.-other affiliation
Šišková A.O.-other affiliation
Arinstein A.-Technion-Israel Institute of Technology (IL)
Sajkiewicz P.-IPPT PAN
Zussman E.-Technion-Israel Institute of Technology (IL)
Stachewicz U.-AGH University of Science and Technology (PL)
2.Alhazov D., Gradys A., Sajkiewicz P., Arinstein A., Zussman E., Thermo-mechanical behavior of electrospun thermoplastic polyurethane nanofibers, EUROPEAN POLYMER JOURNAL, ISSN: 0014-3057, DOI: 10.1016/j.eurpolymj.2013.09.028, Vol.49, pp.3851-3856, 2013
Abstract:

Analysis of the thermo-mechanical behavior of electrospun thermoplastic polyurethane (TPU) block co-polymer nanofibers (glass transition temperature ∼−50°C) is presented. Upon heating, nanofibers began to massively contract, at ∼70°C, whereas TPU cast films started to expand. Radial wide-angle X-ray scattering (WAXS) profiles of the nanofibers and the films showed no diffraction peaks related to crystals, whereas their amorphous halo had an asymmetric shape, which can be approximated by two components, associated with hard and soft segments. During heating, noticeable changes in the contribution of these components were only observed in nanofibers. These changes, which were accompanied with an endothermic DSC peak, coinciding with the start of the nanofibers contraction, can be attributed to relaxation of an oriented stretched amorphous phase created during electrospinning. Such structure relaxation becomes possible when a portion of the hard segment clusters, forming an effective physical network, is destroyed upon heating.

Keywords:

Block-copolymer, Electrospinning, Nanofibers, Thermo-mechanical properties

Affiliations:
Alhazov D.-Technion-Israel Institute of Technology (IL)
Gradys A.-IPPT PAN
Sajkiewicz P.-IPPT PAN
Arinstein A.-Technion-Israel Institute of Technology (IL)
Zussman E.-Technion-Israel Institute of Technology (IL)

Conference abstracts
1.Alhazov D., Gradys A., Denis P., Sajkiewicz P., Arinstein A., Zussman E., Thermo-mechanical behavior of electrospun thermoplastic polyurethane nanofibers, EPF2013, European Polymer Congress, 2013-06-16/06-21, Pisa (IT), pp.O2-23, 2013