The jetting behavior of viscoelastic Boger fluids during centrifugal spinning

Abstract

We present an experimental visualization study of centrifugal spinning, which is a novel method of producing nanofibers. The investigation was conducted using Newtonian and viscoelastic fluids to study the effect of viscoelasticity, driving force, and the flow rate on the initial thinning behavior, jet contour shapes, and radii. Boger fluids based on Newtonian polybutene and viscoelastic polyisobutylene were utilized as test fluids in the current study. Our results reveal that increasing the viscoelasticity leads to a faster initial thinning of the polymer jet. However, the effect is strongly coupled with the rotation speed, and due to a faster increase in extensional viscosity for highly viscoelastic fluids, the thinning slows down with the increase in the angular velocity. Initial thinning is shown to be faster for the lower flow rates. Viscoelasticity and centrifugal force have a significant influence on the jet contour radii. The maximum radius will decrease for more viscoelastic fluids, and with the increase in angular velocity due to the development of the elastic hoop stress. The comparison of experiments with the discretized element modeling with the FENE-P model confirms the model predictive potential for the thinning behavior. Finally, the centrifugal spinning experiments are compared to electrospinning in order to observe a qualitative similarity.

Influence of Polymer Concentration and Nozzle Material on Centrifugal Fiber Spinning

“…According to several published studies, the fiber morphology depends on the polymer concentration, molecular weight, centrifugal speed, collector distance, and nozzle diameter [26][27][28][29]. Even though the centrifugal spinning technique has attracted a lot of interest, and the number of publications has increased tremendously due to its simplicity and its ability to produce fibers at a large scale, control over the fiber morphology remains the major limitation to upscaling [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45]. In this contribution, we investigate the role of both concentration-dependent variation in shear viscosity and the choice of nozzle material on the fiber morphology.…”

A comprehensive mathematical model for nanofibre formation in centrifugal spinning methods

“…Experimental work has also documented the effects of polymer rheological behaviours on CS. For example, Zhmayev et al (2015) and Ren et al (2015) have studied the effect of the polymer solution viscoelasticity on the fibre radius and trajectory and the latter publication has also considered the effects of viscoelasticity and surface tension on the jet breakup. Although experimental methods can be used to study CS parametrically, one needs to devote a large amount of time and effort to deliver a comprehensive understanding of the process.…”

Impact of Apparatus Orientation and Gravity in Electrospinning—A Review of Empirical Evidence

“…This driving force is exacerbated when an electric field is applied. Several papers have addressed this topic, and it seems to be the only area where there is a consensus—regardless of whether it is solution or melt electrospinning, gravity is so weak compared with the centrifugal force that its effects are negligible [ 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 ].…”