Permeability of electrospun fiber mats under pressure driven flow

Hydraulic permeability of electrospun fiber mats under flow-induced compression has been modeled and verified experimentally. The permeation model accurately estimates the changes in solidity, and hence the permeability of the electrospun mats, over a range of pressure differentials. The model is based on Darcy’s law applied to a compressible, porous medium, using Happel’s equation for the permeability and Toll’s equation for the compressibility of fiber mats. Hydraulic permeability of electrospun mats of bis-phenol A polysulfone (PSU) comprising fibers of different mean diameter, annealed at temperatures at and above the glass transition of the polymer, was measured for feed water pressures ranging from 5 kPa to 140 kPa. The electrospun mats are found to experience a decrease of more than 60% in permeability constant between 5 and 140 kPa due to the loss of porosity resulting from the flow-induced compression.