Fig. 6: Fine hair array printing using 3DPX.
From: Fast 3D printing of fine, continuous, and soft fibers via embedded solvent exchange
a Schematic illustrations showing a hair array printing process and printing mechanism. b, c SEM images of printed hair array. (diameter = 76 ± 1 µm) on PDMS substrate. A metal nozzle with a diameter of 210 µm was used for printing. d Photograph of hair array printed with fluorescent polymer ink. The image was obtained by exposing the sample to 365 nm UV light. e Design of straight unit hair and its array. Photograph of (f) the printing process of straight hair array and (g) printed straight hair array. h SEM image of straight hair array with a diameter of 28 ± 3 µm. i Design of coil unit hair and its array. Photograph of (j) the printing process of coil hair array and (k) printed coil hair array. l SEM image of coil hair array with a diameter of 43 ± 4 µm. A metal nozzle with a diameter of 50 µm was used for printing. Three types of fine and long hair strands: (m) Straight, with a diameter of 1.5 µm and a length of 1628 µm, exhibiting an aspect ratio (AR) of 1085; (n) Bent, with a diameter of 1.7 µm and a length of 1751 µm, exhibiting an AR of 1030; and (o) Coiled, with a diameter of 2.2 µm and a length of 7511 µm, exhibiting an AR of 3414. A glass nozzle with a diameter of 5 µm was used for printing.
