Instytut Podstawowych Problemów Techniki
Polskiej Akademii Nauk

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Gleb Vasilyev

Technion - Israel Institute of Technology (IL)

Ostatnie publikacje
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

Streszczenie:
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.

Słowa kluczowe:
fibers, electrical polarity, charges, electrospinning, PMMA, mechanical properties

Afiliacje autorów:
Ura D.P. - AGH University of Science and Technology (PL)
Rosell-Llompart J. - inna afiliacja
Zaszczyńska A. - IPPT PAN
Vasilyev G. - Technion - Israel Institute of Technology (IL)
Gradys A. - IPPT PAN
Szewczyk P.K. - inna afiliacja
Knapczyk-Korczak J. - inna afiliacja
Avrahami R. - inna afiliacja
Šišková A.O. - inna afiliacja
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)
140p.
2.  Boas M., Gradys A., Vasilyev G., Burman M., Zussman E., Electrospinning polyelectrolyte complexes: pHresponsive fibers, SOFT MATTER, ISSN: 1744-683X, DOI: 10.1039/c4sm02618g, Vol.11, pp.1739-1747, 2015

Streszczenie:
Fibers were electrospun from a solution comprised of oppositely charged polyelectrolytes, in efforts to achieve highly confined macromolecular packaging. A stoichiometric ratio of poly(allylamine hydrochloride) and poly(acrylic acid) solution was mixed in an ethanol–water co-solvent. Differential scanning calorimetry (DSC) analysis of electrospun fibers demonstrated no indication of glass transition, Tg. Infrared spectroscopy (FTIR) analysis of the fibers as a function of temperature, demonstrated an amidation process at lower temperature compared to cast film. Polarized FTIR indicated a preference of the functional groups to be perpendicular to the fiber axis. These results imply formation of mixed phase fibers with enhanced conditions for intermolecular interactions, due to the highly aligned and confined assembly of the macromolecules. The tunable intermolecular interactions between the functional groups of the polyelectrolytes, impact pH-driven, reversible swelling–deswelling of the fibers. The degree of ionization of PAA at pH 5.5 and pH 1.8 varied from 85% to 18%, correspondingly, causing transformation of ionic interactions to hydrogen bonding between the functional groups. The chemical change led to a massive water diffusion of 500% by weight and to a marked increase of 400% in fiber diameter, at a rate of 0.50 μm s−1. These results allow for manipulation and tailoring of key fiber properties for tissue engineering, membranes, and artificial muscle applications.

Słowa kluczowe:
polyelectrolytes, electrospinning, pH responsive fibers

Afiliacje autorów:
Boas M. - Technion - Israel Institute of Technology (IL)
Gradys A. - IPPT PAN
Vasilyev G. - Technion - Israel Institute of Technology (IL)
Burman M. - Technion - Israel Institute of Technology (IL)
Zussman E. - Technion - Israel Institute of Technology (IL)
40p.

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