Using Dimensionless Numbers to Predict Centrifugal Jet-Spun Nanofiber Morphology

Abstract

In this study, we report a method for predictive, controlled, and highly aligned nanofiber production via Centrifugal Jet Spinning (CJS) using polycaprolactone (PCL) as a model polymer. We investigated the effects of fabrication conditions and their resulting dimensionless parameters, namely the Weber, Reynolds, and Capillary numbers, by correlating with fiber morphologies (fiber diameter, fiber alignment, bead frequency, bead aspect ratio, and scaffold porosity) and mechanical properties (linear modulus and ultimate tensile strength). We report a fabrication parameter lookup table based on the aforementioned dimensionless numbers, for the production of nanofiber scaffolds using the CJS. We built a scaled-up version of the CJS that uses a larger reservoir and successfully validated the reported lookup table for PCL as well as other polymers including polyethylene oxide, polylactic acid, and polyvinylpyrrolidone dissolved either in hexafluoroisopropanol or chloroform. We show that by carefully tailoring the polymer intrinsic properties and the Reynolds number, we can fabricate bead-free, continuous fibers. This method will allow other researchers to design and build their own CJS for the production of desired fiber scaffold networks by utilizing the appropriate dimensionless numbers for their system.

High Efficiency Fabrication of Chitosan Composite Nanofibers with Uniform Morphology via Centrifugal Spinning

“…The formation of nanofibers could be described by a group of dimensionless parameters, including Reynolds number (Re), Weber number (We), Capillary number (Ca) and Weissenberg number ( W i ) [43]. These dimensionless parameters only described the jet trajectory and fiber formation, but could not predict final diameter of the fibers [44]. As these dimensionless parameters only contained intrinsic solution properties, other key parameters (such as rotational speed, nozzle diameter and nozzle length) were excluded.…”

Quantifying heart valve interstitial cell contractile state using highly tunable poly(ethylene glycol) hydrogels

“…While being able to reproduce many of the VIC-ECM connection features, the PEG gel used in this study is not a fibrous system and therefore cannot mimic the local AVIC micro environment exactly and thus disallows a collective preferred direction of the encapsulated AVIC population. However, this can be mediated in the future with the application of uniaxial constraints [42], incorporation of highly tunable polymeric fibers [43,44], or stretch [45] using our established tissue strip bioreactor system to direct cellular alignment [5]. An increase in cellular alignment should help the collective contraction of AVICs to be more pronounced, and thus measurable, on the macro level.…”

Influence of Polymer Concentration and Nozzle Material on Centrifugal Fiber Spinning

“…Finally, the third characteristic timescale, τ 3 , is determined by the diffusion coefficient (D), of the solvent through the drying polymer with jet radius, r [21][22][23][24][25]. 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].…”