Shear-electrospinning: extending the electrospinnability range of polymer solutions

Electrospinning is recognised as an easily implementable method for the productionof submicron-diameter polymer fibres. However, electrospinning isproblematic for polymers such as biologically derived materials because of theirhigher viscosity. In this study, a new spinneret design applies shear forces to thepolymer solution just prior to electrospinning. The efficacy of shear-electrospinningis proven using concentrated poly(vinyl alcohol) (PVOH) solutions asa model, with solutions designed around the various concentration regimes ofPVOH, initially identified via rheological studies. Conventional electrospinningof solutions up to 16.8 wt% PVOH and viscosity in the order of 101 Pa s leads tothe formation of ribbon-like fibres. In contrast, shear-electrospinning producesfibres finer in diameter, rounder in cross-section and smoother. Finally, fibreformation from solutions that are non-electrospinnable under conventionalelectrospinning is shown for the first time to be achievable via shear-electrospinningas demonstrated for a 30 wt% PVOH solution.