Direct-ink-write printing of hydrogels using dilute inks

Xiaotian Li; Ping Zhang; Qi Li; Huiru Wang; Canhui Yang

doi:10.1016/j.isci.2021.102319

Direct-ink-write printing of hydrogels using dilute inks

iScience. 2021 Mar 18;24(4):102319. doi: 10.1016/j.isci.2021.102319. eCollection 2021 Apr 23.

Authors

Xiaotian Li¹, Ping Zhang¹, Qi Li¹, Huiru Wang¹, Canhui Yang¹

Affiliation

¹ Department of Mechanics and Aerospace Engineering, Southern University of Science and Technology, Shenzhen 518055, China.

Abstract

Direct-ink-write (DIW) printing has been used in myriad applications. Existing DIW printing relies on inks of specific rheology to compromise with printing process, imposing restrictions on the choice of printable materials. Reported ink viscosity ranges from 10^-1 to 10³ Pa·s. Here we report a method to enable DIW printing that is compatible with dilute ink (10^-3 Pa·s) by manipulating the interactions between ink and substrate. By exemplifying hydrogel printing, we build a printing system and show that dilute ink of appropriate surface energy, once extruded, can spontaneously wet and reside within the region of higher surface energy on a substrate of lower surface energy, while resisting gravity and maintaining shape before solidification. We demonstrate the diversity for printing various materials on various substrates and three deployments immediately enabled by the proposed method. The method expands the range of printable materials for DIW printing and the toolbox for additive manufacturing.

Keywords: Materials Processing; Materials Science Engineering; Surface Science.