Dependence of poly(vinyl butyral) electrospun fibres diameter on molecular weight and concentration

In electrospinning, a proper choice of a mean diameter for electrospun fibres plays a significant role in a number of applications. The diameter is dependent on various entry parameters (concerning polymer, solvent, solution or the process of electrospinning itself) and is qualitatively evaluated based on a series of experiments. However, the studies on quantitative evaluation are rather scarce. The aim of this contribution is to propose and experimentally verify simple algebraic relationships; interlacing the mean diameter, concentration of poly(vinyl butyral) (PVB) dissolved in ethanol, molecular weight, and viscosity. The proposed explicit relationship for evaluating a mean diameter is valid for discrete values of specific molecular weights and is also applicable in continuous ranges of the studied parameters with a mean deviation not exceeding 10%, where PVB molecular weight is 30-60 kg/mol and PVB concentration is full range. Hence, it also provides the ability to determine optimised values of molecular weight for a chosen mean diameter including a dispersion of its value dependent on dispersion of molecular weights for the individual PVB charges. A direct evaluation of mean diameter can substitute a classical trial-and-error method for determining a required diameter.