Crimped polymer microfibers produced via electrospinning: A review Nikolas J. Vostala Department of Mechanical Engineering and Material Science University of Pittsburgh, PA, USA a
Nikolas Vostal
Nikolas Vostal is a Junior at Pitt studying Materials Science and Engineering who grew up in Plymouth, Michigan. His interests lie in polymer engineering and composite material design, although outside the classroom he is the president of Pitt’s Material Advantage Chapter and a member of the Pitt Squash team.
Significance Statement
Materials with high strength often suffer from poor flexibility and vice versa. Composites reinforced with crimped microfibers can allow excellent flexibility at low strain but high strength at high strain. This work reviews methods to create such fibers by means of electrospinning and their potential applications.
Category: Review Paper
Keywords: electrospinning, crimped fibers, polymer microfibers
Abstract
Until recently, the production of small-diameter fibers and other micro-scale materials have been expensive and difficult. However, in recent years electrospinning has become popular as a plausible, cost-effective means of creating microfibers for a number of different applications. It has also been found that by adjusting the setup of electrospinning, it is possible to create patterned microfibers with unusual properties. One possibility is the creation of crimped microfibers whose wavy nature allows them to be extremely flexible until sufficient strain is applied to straighten them. On a large-scale, mats comprising crimped fibers can be used to create materials which can reliably deform and return to their original position. Such properties have applications in many different fields, most notably the biomedical field, where crimped fibers can mimic the wavy collagen fibers found in organic tissue. This article reviews many of the successful methods of producing crimped nanofibers and their current applications.
1. Introduction
Electrospinning is a simple and versatile method of creating polymeric microfibers. The most basic electrospinning setup utilizes a syringe of polymer solution placed into a syringe pump [1]. The tip of the syringe is electrically charged via a high voltage generator while a nearby metallic collector is grounded. As the solution is slowly pumped out of the syringe, charge builds up around the droplet that forms at the tip of the needle. The built-up charge causes a portion of the droplet to jump across the gap, stretching and drying along its path and hence landing on the collector as a micron-sized fiber [2]. As the pump continues to expel solution, fibers land randomly across the collector, forming a nonwoven mat. While these random mats have found numerous applications, it is also possible to alter the shape and movement of the collector so that fibers land in an oriented fashion with transverse isotropy [3-5]. Aligned fiber mats can be woven to fabricate complex micropatterns that have greater tensile resistance [2].
Figure 1: Diagram of a typical electrospinning setup, Reproduced from Ref 6.
102 Undergraduate Research at the Swanson School of Engineering
