Improving Electrospun Nanofiber Strength for Filtration Applications

Electrospun nanofibers have recently been considered for water filtration.  These nano-scale fibers have a high specific surface area combined with a high permeability, thus enabling their use in low pressure microfiltration and adsorption based separations.  However, electrospun nanofibers are generally characterized as having weak mechanical properties.  As such, they are typically attached to a secondary support, such as a polyester nonwoven.   The use of non-woven fabric might be unfavorable because it could increases the filtration resistance, especially in low pressure filtration.

In this study we present several methods for increasing the strength of standalone electrospun nanofibers.  Our initial polymers in this study include polysulfone and polyacrylonitrile, two polymers commonly used in filtration applications.  Through tuning of the spinning parameters (humidity and solvent), we were able to control the tensile strength  and modulus of the nanofiber mats.  Post treatment of the nanofibers also resulted in increased strength.  Fiber size, surface area, morphology and pore size/structure were also characterized during this study.