Electrospinning of Tough and Elastic Liquid Crystalline Polymer–Polyurethane Composite Fibers: Mechanical Properties and Fiber Alignment

Abstract

Tough and elastic microfiber composites composed of an elastic polyurethane (Hydrothane) and a liquid crystalline polymer (Vectran) are fabricated via electrospinning. The composite fibers (HVC) are examined as a function of the mixing ratio of the polymers and evaluated on the bases of fiber formation, morphology, thermal properties, mechanical performance, and fiber alignment. The fiber diameters of the HVCs decrease as the content of Vectran increases. When the fibers are aligned via a rotating target, they have even smaller diameters and increased uniformity than when a static target is employed. Surprisingly, the aligned fibers’ mechanical properties are different than those of random orientation; the HVC fibers of random orientation display increases in strength, toughness, and elastic modulii when increasing amounts of Vectran are incorporated in the fibers. The aforementioned mechanical properties of the aligned fibers decrease somewhat as the content of Vectran is increased. Further, the durability of the aligned fibers is examined by extensional durability tests over ten cycles. The tests indicate that the HVC fibers are very durable and can function as tunable, tough, and elastic fibrous polymer scaffolds and have potential applications in high‐performance composites, polymeric filtration devices, and fibrous bioengineering materials.

Electrospun Nanofibrous Membranes for Tissue Engineering and Cell Growth

“…As previously mentioned, aligned nanofiber mats can be advantageous for cell growth. They can be prepared by using a rapidly rotating collector along with blades [17,18,29]. For special cases, as with magnetic nanofibers, a magnetic field can be used to support fiber alignment [19,30], while introducing conductive, and ideally also grounded, areas in the substrate can also be used to prepare oriented nanofiber mats [31].…”

“…Besides the large specific surface of such nanofiber mats, specific electrospinning techniques or substrate preparations enable spinning oriented fibers, which is not only supportive in terms of mechanical properties, but also for growing cells on these substrates in a defined orientation and in many cases with a higher proliferation rate [17][18][19][20].…”

Orientation of Electrospun Magnetic Nanofibers Near Conductive Areas

“…In the literature, different approaches can be found to reach this goal. Often a high-speed rotating collector is used [21][22][23], but fiber orientation can also be reached by using a pair of blades as the collector [24,25] or stretching the electrospun mat in ethanol [2].…”

Controlled release of the insect repellent picaridin from electrospun nylon‐6,6 nanofibers

“…Electrospinning is a facile method for the fabrication of microscale and nanoscale polymer fibers 15 . Recently, electrospinning has shown broad capability to generate a variety of polymer fibers of single and composite composition 16‐18 . Electrospun polylactic acid fibers containing DEET at concentrations exceeding 50 wt% demonstrated uniform fiber morphology and delayed evaporation of DEET as compared to the neat repellent 19,20 .…”

“…15 Recently, electrospinning has shown broad capability to generate a variety of polymer fibers of single and composite composition. [16][17][18] Electrospun polylactic acid fibers containing DEET at concentrations exceeding 50 wt% demonstrated uniform fiber morphology and delayed evaporation of DEET as compared to the neat repellent. 19,20 Furthermore, electrospun pyromellitic dianhydride-cyclodextrin-based fibers were loaded with DEET and shown to maintain fiber morphology, as well as provide increased release times.…”