5.13 Electrospinning with polymer melts - state of the art and future perspectives

It is broadly valued by the biomaterials community that electrospinning from both the solution and melt is a technologically attractive method to process polymeric and composite materials; yet the number of publications reported in the current scientific literature regards the two methods has an estimated ratio of 1 to 400. Among the many reasons for the currently limited research output in melt electrospinning (MES) is that the fabrication of a well-designed melt-based electrospinning devices is technologically and scientifically more challenging than assembling a laboratory-scaled bench top solution electrospinning (SES) machine. Interestingly, the traditional polymer science-rooted MES community has for the most part published studies using micron-diameter fibers; however, the biomaterials community prefers scaffold-processing technologies that allow the fabrication of submicron architectures. From a manufacturing point of view and compared to other fiber forming processes, less operational volatility is induced, as MES is a solvent-free process. Additionally to this key aspect and from a users’ safety perspective, no further concerns exist in regards to toxicity. If controlled appropriately, the charged polymer jet, which is formed during MES can be accurately directed to the collector without instabilities. Through the application of MES in a direct writing mode, i.e., the implementation of moving stages in two dimensions (X and Y), the resulting process can be considered as a new class of three-dimensional (3D) printing. This article reviews MES research from a polymer processing and machine design point of view. It concludes postulating that the emergence of the progressive, innovative, and creative MES technology will increasingly supersede the conventionally used SES until it becomes successfully established within the biomaterials community.