摘要：SummaryDirect-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 10−1to 103Pa·s. Here we report a method to enable DIW printing that is compatible with dilute ink (10−3Pa·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.Graphical abstractDisplay OmittedHighlights•Direct-ink-write printing is advanced to be compatible with dilute ink (10−3Pa·s)•The interaction between ink and substrate is mediated by tuning surface energies•The method is applicable for printing various materials on various substratesMaterials Processing; Surface Science; Materials Science Engineering
