Realization of devices with enhanced stretchability and waterproof properties will significantly expand the reach of electronics. To this end, we herein fabricate an elastic transparent conductor that comprises silver nanowires (AgNWs) on a hydroxylated polydimethylsiloxane (PDMS) substrate covered by polyurethane urea (PUU), which is fully compatible with both materials. Carboxylic acid groups of PUU was designed to form hydrogen bonds with the carbonyl groups of poly(vinylpyrrolidone) on the AgNW surface, resulting in an enhanced affinity of AgNWs for PUU. Exceptionally strong hydrogen bonds between PUU and the hydroxylated PDMS thus facilitate the achievement of water sealable, mechanically stable, and stretchable transparent electrodes. To fabricate stretchable electroluminescence (EL) devices, ZnS particles were mixed with PUU, and the mixture was coated onto the AgNWs/hydroxylated PDMS, followed by a face-to-face lamination with another identical electrode. The devices could be stretched up to 150% without a severe reduction in the emission intensity, and they survived 5000 cycles of 100% stretch-release testing. The high adhesion between PUU and PDMS even in water is responsible for the good waterproof characteristics of the EL devices. These results pave the way for realization of fully stretchable and waterproof electronic devices.
Keywords: electroluminescence; polyurethane urea; silver nanowire; stretchable device; waterproof.