Title: Fluid Microchannel Encapsulation to Improve the Stretchability of Flexible Electronics

Abstract: Recently, stretchable inorganic electronic devices are rapidly developed, comprising emerging design strategies and fabrication techniques for assembling high-performance electronic components in slight, soft, and flexible forms, with broad medical and industrial applications. Although reliable encapsulation plays an indispensable role in offering physical and chemical protection for flexible devices, there are relatively few studies on flexible encapsulation, and conventional encapsulation methods still suffer from low stretchability. Herein, a generic fluid microchannel encapsulation method is proposed, in which the device interconnects are wrapped by ultraminiaturized fluid microchannels, enabling free bucking during deformation to tremendously improve the device stretchability. Experimental analysis and finite element analysis demonstrate the substantial stretchability enhancement for the proposed method in contrast to the conventional method, which can increase by ≈100% for general 2D serpentine interconnects and ≈360% for fractal 2D serpentine interconnects. Additionally, a highly stretchable LED device serves as an example to demonstrate the utility of the proposed method for maintaining such an enormous stretchability improvement at the device level.