This paper presents a comprehensive experimental and theoretical description of the use of electrical forces to create polymer nanofibers from polymer solutions. The electrically driven, bending, and elongating part of the jet of solution that creates nanofibers was shown to have the surprising property that each segment follows a trajectory which is almost perpendicular to the path of that segment of the coiled jet. This almost magical process has become the method of choice for creating nanofibers from a wide variety of polymers. The paper is a "Rosetta Stone" between experiment and theory. The experimental section is written in the language of polymer physics, using mks units and relying on 3-dimensional, time varying images for much of the data. The theoretical section is in the language of fluid dynamics, using cgs units and dimensionless variables. Computer modeling was used to bring the two approaches together at many points.

It has been somewhat difficult to produce polymer fibers in laboratory-scale apparatus. Electrospinning now makes it easy to produce polymer nanofibers just at a time when materials science is concentrating on nanometer scale phenomena. Nanofibers that were previously unavailable are now finding use in areas that include filtration, biomedicine, energy conversion, catalysis, exploration of outer space, and biology.

Darrell Reneker is an experimental physicist, with a background in electrical engineering and polymer morphology, who used empirical electrospinning to manufacture polymer nanofibers. Alexander Yarin is a mechanical engineer with extensive experience in theoretical descriptions of fluid jets and an interest in electrified jets. A colleague introduced us. Our complementary interests were immediately evident, and we found financial support for our joint efforts that produced this paper and a continuing series of related papers. Hao Fong and Sureeporn Koombhongse were graduate students at the University of Akron, Department of Polymer Science.

Nanofibers, with diameters much thinner than the finest fibers in textiles, bring new, useful capabilities to: air and liquid filters; clothing that neutralizes a variety of potentially harmful airborne substances; wound dressings, applied painlessly, that accelerate healing and kill micro-organisms; improved stents for relieving blockages in the arteries of the heart and the brain. Nanofibers are being used to engineer a wide variety of useful nanometer scale structures, mechanisms, energy converters, and sensors.

View image. Description: bending and elongating coiled jet of polymer solution on its way to becoming a polymer nanofiber.  This behavior was observed and mathematically modeled in the work described in the "highly cited paper".  The image is taken from a high frame rate video of an electrospinning jet of polyethylene oxide dissolved in a mixture of water and alcohol.