Figure 11.

3D printing of conducting electronic inks. (A) Omni-directional printing of a concentrated silver ink to form the interconnects of an LED chip array. The inset shows an interconnect arch printed over a junction [90]. (B) 3D printing of free-standing liquid metal into a cubic array of stacked droplets (top inset), a 3D metal arch (middle inset), an arch overpassing a printed wire (bottom inset), and a tower of liquid metal droplets. Scale bars are 500 μm [70]. (C) 3D printing of a silver nanoparticle ink on a three dimensional surface to form an antenna [191]. (D) Embedded 3D printing of conducting carbon grease in an uncured elastomeric polymer (inset) enables the creation of stretchable strain sensors embedded within a glove [192]. (E) Co-printing of a conductor within a cell-laden biological scaffold to create a bionic ear. (F) Biocompatibility of the printed electronics within the biological construct. The fluorescent image (bottom) shows the viability of the neo-cartilaginous tissue in contact with the electrode (top) [67]. (G) Electromagnetic response of the 3D printed bionic ear. Plot shows the S21 transmission coefficient with frequency, demonstrating the capability of receiving signals over an expansive frequency range [67]. Reprinted with permission from Refs. [90], [70], [191], [192], [67], respectively. Copyright 2009 American Association for the Advancement of Science, 2011 John Wiley & Sons, 2014 John Wiley & Sons, 2013 American Chemical Society.