Melt electrospinning today: An opportune time for an emerging polymer process

Over the last decade, melt electrospinning has emerged as an alternative polymerprocessing technology to alleviate concerns associated with solvents in traditional elec-trospinning. This has resulted in the fabrication of ultrafine fibers from an increasing rangeof synthetic polymers and composite systems, to materials including ceramics, drivingnew applications in technical areas such as textiles, filtration, environment and energyas well as biomedicine. In this article, we review the significant advancements in theoret-ical modeling of the underlying physical principles, coupled with experimental validationusing a variety of technical devices and designs that allows well-controlled fiber formationusing optimized material and operating parameters. Innovative device designs are indi-cating avenues towards higher throughput of randomly collected melt electrospun fibersfor the production of commodity nonwoven substrates, similar to solution electrospinningand many other industrial fiber-forming processes. However, we identify a recent shift inperception towards melt electrospinning in the literature, where the adaptation of additivemanufacturing approaches to device designs enables precise fiber placement with filamentresolutions not yet demonstrated by more established melt-extrusion based direct writingtechnologies. New, highly ordered arrangements of ultrafine fibers with distinctive surfacetopology, encapsulating and sensing properties are opening new fields of application inareas such as drug delivery, biosensors and regenerative medicine as high performancematerials. The development of these materials is reviewed with an emphasis on an area ofcurrent research, where melt electrospun scaffolds are contributing to promising treatmentstrategies to regenerate or replace human tissue and for the new field of in vitro diseasemodels as well as humanized mice models.