Nanoribbons fabricated by melt electrospinning

This study focuses on using the multilayer melt electrospinning of polymers in combination with a delamination step to obtain nonwoven webs of ribbon-shaped flat fibers that are ~150 to 200 nm thick. A novel coextrusion system with layer multipliers is used to melt electrospin bicomponent cylindrical microfibers with diameters in the range of ~15–25 μm that have up to 257 alternating layers within each fiber prior to delamination. The diameter of the cylindrical fibers is dependent on the temperature, the flow rate of the polymers, and the die tip-to-collector distance. The fabricated bicomponent layered microfibers are subsequently delaminated using sonication or solvent rinsing to obtain flat nanoribbons whose thicknesses vary from 150 to 200 nm. After delamination, some of the flat nanoribbons are found to roll into cylindrical fibers with diameters ranging from 150 to 250 nm. This bicomponent approach uses a continuous melt extrusion process that can support higher throughputs compared to traditional solution electrospinning and can lead to the fabrication of high surface area nonwoven webs after proper delamination treatments.