Electrospun Nanofibers with Associative Polymer-Surfactant Systems

Associative polymers are unique in their structure with pendant hydrophobes attached to their hydrophilic backbone, enabling associations between the hydrophobes and forming junctions in aqueous solutions. In this study, we examine efforts to produce electrospun nanofibers of associative polymers in conjunction with a readily spinnable polymer. Scanning electron micrograph (SEM) images reveal that the solution rheology sets an upper limit to the concentration of associative polymer that can be successfully electrospun. However, addition of nonionic surfactants to the precursor solution results in significant improvement in nanofiber morphology as evinced from reduced heading. Through judicious use of nonionic surfactants to modulate solution viscoelastic properties, we are able to obtain defect-free nanofiber morphology and gain new insights into the fundamentals of the electrospinning process. In particular, we find that solution viscoelasticity as measured in terms of the relaxation time, rather than viscosity as typically hypothesized, controls the nanofiber formation process.