Electrospinning Using AC Electric Fields.

Electrospinning is increasingly used as a staple technology for the fabrication of nano- and micro-fibers of different materials. Most processes utilize direct current (DC) electrospinning, and a multitude of DC-electrospinning tools ranging from research to commercial production systems is currently available. Yet, there are numerous studies performed on electrospinning techniques utilizing non-DC, periodic electric fields, or alternating current (AC) electrospinning. Those studies demonstrate the strong potential of AC-electrospinning for the sustainable production of various nanofibrous materials and structures. Although tremendous progress is achieved in the development of AC-electrospinning over the last 10 years, this technique remains uncommon. This paper reviews the AC-electrospinning concepts, instrumentation, and technology. The main focus of this review is the most studied, "electric wind" driven AC-electrospinning technique tentatively named alternating field electrospinning (AFES). The latter term emphasizes the role of the AC electric field's confinement to the fiber-generating electrode and the absence of a counter electrode in such an electrospinning system. The synopses of AFES process parameters, fiber-generating spinneret designs, benefits and obstacles, advancements in AC electrospun nano/micro-fibrous materials/structures and their applications are given, and future directions are discussed.