Stabilization of Electrospun Nanofiber Mats Used for Filters by 3D Printing

Abstract

Electrospinning is a well-known technology used to create nanofiber mats from diverse polymers and other materials. Due to their large surface-to-volume ratio, such nanofiber mats are often applied as air or water filters. Especially the latter, however, have to be mechanically highly stable, which is challenging for common nanofiber mats. One of the approaches to overcome this problem is gluing them on top of more rigid objects, integrating them in composites, or reinforcing them using other technologies to avoid damage due to the water pressure. Here, we suggest another solution. While direct 3D printing with the fused deposition modeling (FDM) technique on macroscopic textile fabrics has been under examination by several research groups for years, here we report on direct FDM printing on nanofiber mats for the first time. We show that by choosing the proper height of the printing nozzle above the nanofiber mat, printing is possible for raw polyacrylonitrile (PAN) nanofiber mats, as well as for stabilized and even more brittle carbonized material. Under these conditions, the adhesion between both parts of the composite is high enough to prevent the nanofiber mat from being peeled off the 3D printed polymer. Abrasion tests emphasize the significantly increased mechanical properties, while contact angle examinations reveal a hydrophilicity between the original values of the electrospun and the 3D printed materials.

Magnetic Properties of Electrospun Magnetic Nanofiber Mats after Stabilization and Carbonization

“…Electrospinning makes it possible to create nanofiber mats from diverse materials, such as pure polymers [1][2][3], polymers blends, composite fibers from polymers and ceramics or metals [4,5], and cyclodextrins [6]. These can be used in diverse applications such as filters [7][8][9], biotechnology and tissue engineering [10][11][12], for energy harvesting and storage [13,14], or other "smart" functions [15]. Recently, a strong focus of diverse research groups has been related to electrospinning magnetic nanofibers, either as composites [16][17][18] or, after calcination of the composites to remove polymers, as pure metal nanofibers [19][20][21].…”

Electrospinning on 3D Printed Polymers for Mechanically Stabilized Filter Composites

“…Although 3D printing on electrospun nanofiber mats is quite challenging [23], the reversed process is not technologically complex. Electrospinning on a 3D printed PLA object resulted in the surface depicted in Figure 1, showing one of the denser ( Figure 1a) and one of the less dense regions in which the 3D-printed surface is visible below the nanofibers (Figure 1b).…”

“…This was even less than in the previous examination on nanofiber mats that were approx. twice as thick [23] which could withstand 5-10 Martindale cycles in the dry state, but were also destroyed after one Martindale cycle in the wet state. Figure 6 shows microscopic images after 1, 20, and 100 Martindale cycles, respectively.…”

Stress Relaxation and Creep of a Polymer-Aluminum Composite Produced through Selective Laser Sintering

“…Additive manufacturing technologies are suitable to print geometrically intricate internal structures, e.g., objects within objects, thin-walled products, or objects with a sponge, cellular or honeycomb structure retaining sufficient strength. Fused deposition modelling (FDM) is the most popular 3D printing process for quick and easy fabrication [6,7]. In medicine, for example, FDM technology has been used for hip joint reconstruction.…”