Enhanced adhesion between liquid metal ink and the wetted printer paper for direct writing electronic circuits.

Highlights • Condensed droplets as buffer materials are used to wet the printer paper surface. • On the wetted paper, the liquid metal changes its state from Cassie's to Wenzel's. • Liquid metal can be smoothly written on wetted printer paper. Abstract Liquid metal (In 75.4 Ga 24.5 , LM) with its high electrical conductivity and flexibility at room temperature, has been gradually introduced into printed electronics. However, the low adhesion effect of LM on the common printer paper may restrict its potential value in reducing cost and expanding use. In this study, the surface property of the printer paper has been modified by a wetting method with a coating of micro-size droplets on the paper surface to realize a smooth writing process using the liquid metal ink. The current strategy is expected to enable future flexible electronic circuits on the hard writing substrates. Graphical abstract Liquid metal on the (a1) dried and (b2) wetted printer papers in (a2) Cassie's and (b2) Wenzel's states, respectively, and (c1, c2) obtained cat-writing results. Image, graphical abstract [ABSTRACT FROM AUTHOR]