Study of extrudability and standoff distance effect during nanoclay-enabled direct printing

Abstract

Nanoclay-enabled self-supporting printing has been emerging as a promising filament-based extrusion fabrication approach for different biomedical and engineering applications including tissue engineering. With the addition of nanoclay powders, liquid build materials may exhibit solid-like behavior upon extrusion and can be directly printed in air into complex three-dimensional structures. The objective of this study is to investigate the effect of nanoclay on the extrudability of N -isopropylacrylamide (NIPAAm) and the effect of standoff distance on the print quality during nanoclay-enabled direct printing. It is found that the addition of nanoclay can significantly improve the NIPAAm extrudability and effectively eliminate die swelling in material extrusion. In addition, with the increase of standoff distance, deposited filaments change from over-deposited to well-defined to stretched to broken, the filament width decreases, and the print fidelity deteriorates. A mathematical model is further proposed to determine the optimal standoff distance to achieve better print fidelity during nanoclay-enabled direct printing. Based on the extrudability and standoff distance knowledge from this study, NIPAAm-Laponite nanoclay and NIPAAm-Laponite nanoclay-graphene oxide nanocomposite hydrogel precursors are successfully printed into a three-layered one-dimensional responsive pattern, demonstrating the good extrudability and print quality during nanoclay-enabled printing under optimal printing conditions.

Transformer Hydrogels: A Review

“…Eventually, the internal stresses generated within the materials lead to an out‐of‐plane buckling deformation which is energetically more favorable. Patterning of stimuli‐responsive hydrogels can strategically place these internal stresses to program complex shape transformations …”

Experimental study of polymeric stent fabrication using homemade 3D printing system

“…When the step distance increases from 0.1 to 0.3 mm, the width of struts decreases from 0.425 to 0.368 mm, and the thickness decreases from 0.653 to 0.553 mm. That is because when the step distance is lower than a critical value (usually the thickness of one deposited layer), overdeposited phenomenon can be observed which may lead to a relative larger strut width and uncontrollable strut thickness. However, when the step distance increases higher than the thickness of one deposited layer, there is a gap between the nozzle tip and the layer surface.…”

“…However, when the step distance increases higher than the thickness of one deposited layer, there is a gap between the nozzle tip and the layer surface. Thus, due to the gravity and dragging effect , the deposited filament may have a smaller cross‐sectional area, which results in the decrease of both width and thickness.…”

Three-Dimensional Coprinting of Liquid Metals for Directly Fabricating Stretchable Electronics

“…Stretchable electronics have been developed into novel electronic devices, with extensive potential application in the fields of wearable devices, soft robotics, artificial skin, and other fields. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Stretchable electronics are the products of engineering technology and material science development, especially the rapid development of three-dimensional (3D) printing technology and liquid metals. Liquid metals are very reliable conductive materials in stretchable electronics, and 3D printing offers an accurate and fast way to build the circuits and structures.…”

“…1,5,7,9,36,37 Some methods embed a nozzle into base materials to print planar or 3D circuit patterns. 8,15,31,38 As oxide skin can be formed immediately when GLMs are exposed to air and can improve the printability of GLMs, some researchers directly squeeze out GLM droplets in the air and stack them to form a 3D structure. 39 Based on this, some researchers developed a manufacturing process for the mixed printing of liquid metal inks and nonmetal inks.…”