Direction-dependent stretchability of AgNW electrodes on microprism-mediated elastomeric substrates

Silver nanowires (AgNWs) have become an efficient electrode candidate for stretchable electronics. We report the effects of directional stretching in microprism-mediated AgNW stretchable electrodes on polyurethane (PU) substrates. The wavy substrate is fabricated using a customized microprism on polyethylene terephthalate. AgNWs on stretchable PU substrates show stable normalized resistance up to 35% strain under parallel uniaxial stretching. This performance is much better than AgNWs on bare PU substrate or on wavy PU under perpendicular stretching, which can only sustain 10%-15% strain before significant increase in normalized resistance. Finite element simulations were conducted to reveal the strain distribution and variation in the AgNW electrodes on both bare and wavy PU substrates when stretched along parallel and perpendicular directions. Comparing to AgNW electrodes on bare PU and on wavy PU under perpendicular stretching, the wavy PU surface relief features can effectively alleviate the strain in the AgNW network when stretched along parallel direction, leading to better performance.