2022 journal article

Direct electrohydrodynamic printing of aqueous silver nanowires ink on hydrophobic substrates for flexible and stretchable electronics

Manufacturing Letters, 33, 161–166.

By: P. Ren n & J. Dong n

Contributors: J. Dong n

Source: ORCID
Added: September 21, 2022

Stretchable conductors based on metal nanowires, such as silver nanowires (AgNWs), are essential for the fabrication of stretchable electronics. Electrohydrodynamic (EHD) printing has been developed as a promising technique for patterning various conductive nanomaterials on stretchable substrates. However, the printing performance is adversely affected by poor wettability of the ink on the surface of the stretchable substrates, which are mostly low-surface-energy elastomeric polymers, like polydimethylsiloxane (PDMS). The surface treatments of the substrate surface could improve the printability of the ink on these substrates, but also impose many limitations, as the surface treatment could unfavorably affect the mechanical properties of the polymer and may cause damage to the underlying layer or other existing features on the substrate. The paper investigates EHD direct printing of aqueous AgNWs ink on untreated PDMS using surfactant (i.e., Capstone FS30) modified ink for the fabrication of stretchable electronics. The static contact angles at the different FS30 ratios were measured to analyze their effect on regulating the ink wettability. A set of printing experiments were performance to select the right ink composition to tailor and optimize the ink printability and printing performance. The morphology and electrical properties of printed AgNWs-based conductors can be controlled by selecting different the EHD printing speed. Furthermore, to illustrate the potential for reliable EHD direct printing of AgNWs for stretchable electronics, a wearable electronic patch with a fractal design of the AgNWs pattern was printed on an untreated PDMS substrate using the surfactant modified AgNWs ink, which provides stable electronic response under the bending, tension and compression.