3Dプリント用導電性金属ゲル(Conductive Metallic Gel for 3D Printing)


2023-07-05 ノースカロライナ州立大学(NCState)



導電性3Dおよび4D印刷用金属ゲル Metallic gels for conductive 3D and 4D printing

Ruizhe Xing, Jiayi Yang, Dongguang Zhang, Wei Gong, Taylor V. Neumann, Meixiang Wang, Renliang Huang, Jie Kong, Wei Qi, Michael D. Dickey
Matter  Published: July 5, 2023

3Dプリント用導電性金属ゲル(Conductive Metallic Gel for 3D Printing)

Progress and potential

Four-dimensional (4D) printing refers to 3D-printed structures that change shape with respect to time in response to an external stimulus. To date, 4D printing techniques have focused primarily on electrically insulating materials such as polymers. Adding conductive fillers to polymers could increase the functionality of the printed parts, but the high loadings necessary to achieve conductivity represent a trade-off with printability. Here, we connect copper (Cu) particles with soft eutectic gallium indium alloy (EGaIn) bridges to form a conductive 4D printing ink (Cu-EGaIn) with gel-like properties that are well suited for printing. The final printed parts have a total metal content as high as 97.5 wt %, and the remainder is methylcellulose, a rheological modifier. The printed parts have an extremely high electrical conductivity (1.05 × 105 S/m) without requiring a sintering step. Cu-EGaIn addresses the contradiction between conductivity and printability and should open up new opportunities for electronic, thermal, and composite devices.


This paper reports printable metallic gels (pendular suspensions) consisting of an aqueous suspension of copper particles connected by bridges of liquid eutectic gallium indium alloy (EGaIn). Pendular suspensions rely on capillary forces to form networks between solid particles with a composition-dependent rheology, but prior studies have focused on insulating suspensions. Here, the rheology of a conductive solid-liquid-liquid suspension is tuned for 3D printing by varying the composition and the pH; the latter promotes metallic wetting. The dry printed parts have metallic electrical conductivity (<?XML:NAMESPACE PREFIX = “[default] http://www.w3.org/1998/Math/MathML” NS = “http://www.w3.org/1998/Math/MathML” />1.05×105 S/m) without requiring a sintering step. Drying at elevated temperatures can accelerate the removal of water while creating stress that drives shape change (i.e., 4D printing). As a demonstration, we print a conductive spider that lifts and assembles its own body from an initially flat shape. Such conductive inks are promising for printing metallic structures under ambient conditions.