Features of the Behavior of a Polymer Solution Jet in Electrospinning

Abstract

Using the numerical analysis of the force balance equation and the rheological equation of the model of finitely extensible chains, the dynamics of a charged jet during the electrospinning of a polymer solution and the orientation of macromolecules in the jet are studied. In fairly weak electric fields, the jet always remains rectilinear, while in strong fields the straight section of the jet has a finite length, after which the motion of the jet becomes unstable. This behavior is due to the competition between inertial and viscoelastic forces, with viscoelasticity dominating in strong fields. It is found that polymer chains in the jet are strongly stretched along the flow direction.

The Elasticity of Polymer Melts and Solutions in Shear and Extension Flows

“…It is interesting to note that for low flow rates when , the straight jet has a finite length , where . A similar result was obtained in numerical calculations [ 166 , 167 ]. In this case, the orientation parameter increases along the jet axis as , and reaches its maximum value at the end of the straight section of the jet.…”

“…For large flow rates, , the jet is rectilinear. In this mode, the order parameter changes non-monotonically along the jet: first, it increases up to a certain maximum value (at which the Weissenberg number reduces to ) and then decreases [ 166 , 167 ]. The decrease is associated with the relaxation of the polymer chains.…”

“…The formation of fibers from the jet occurs as a result of the chain orientation, aggregation, and evaporation of the solvent. Numerical calculations have shown that during electrospinning, polymer chains can be strongly elongated along the flow in the rectilinear section of the jet, so that their orientational order parameter reaches the value [ 166 , 167 ]. The high orientation of polymer chains can lead to a phase separation of the polymer solution [ 166 ] with the emergence of string-like structures.…”

Charge transport in electrospinning of polyelectrolyte solutions

“…The jet velocity is typically in the order of 1 m s −1 , so that τ C ≈ τ H and convection of surface charges dominates the current in zones two and three. 32 Despite its limited suitability in fast hydrodynamic phenomena, such as within the second and the third jet zones, scaling relationships for the electric current derived from the LDM, as well as EHD-based models in general, agree with experimental observations when working with neutral polymers. 28…”