A highly stretchable, transparent, and conductive polymer

Yue Wang; Chenxin Zhu; Raphael Pfattner; Hongping Yan; Lihua Jin; Shucheng Chen; Francisco Molina-Lopez; Franziska Lissel; Jia Liu; Noelle I Rabiah; Zheng Chen; Jong Won Chung; Christian Linder; Michael F Toney; Boris Murmann; Zhenan Bao

doi:10.1126/sciadv.1602076

A highly stretchable, transparent, and conductive polymer

Sci Adv. 2017 Mar 10;3(3):e1602076. doi: 10.1126/sciadv.1602076. eCollection 2017 Mar.

Authors

Affiliations

¹ Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA.
² Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA.
³ Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
⁴ Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA.; Department of Civil and Environmental Engineering, Stanford University, Stanford, CA 94305, USA.
⁵ Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA.; Samsung Advanced Institute of Technology, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803, South Korea.
⁶ Department of Civil and Environmental Engineering, Stanford University, Stanford, CA 94305, USA.

Abstract

Previous breakthroughs in stretchable electronics stem from strain engineering and nanocomposite approaches. Routes toward intrinsically stretchable molecular materials remain scarce but, if successful, will enable simpler fabrication processes, such as direct printing and coating, mechanically robust devices, and more intimate contact with objects. We report a highly stretchable conducting polymer, realized with a range of enhancers that serve a dual function: (i) they change morphology and (ii) they act as conductivity-enhancing dopants in poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). The polymer films exhibit conductivities comparable to the best reported values for PEDOT:PSS, with over 3100 S/cm under 0% strain and over 4100 S/cm under 100% strain-among the highest for reported stretchable conductors. It is highly durable under cyclic loading, with the conductivity maintained at 3600 S/cm even after 1000 cycles to 100% strain. The conductivity remained above 100 S/cm under 600% strain, with a fracture strain of 800%, which is superior to even the best silver nanowire- or carbon nanotube-based stretchable conductor films. The combination of excellent electrical and mechanical properties allowed it to serve as interconnects for field-effect transistor arrays with a device density that is five times higher than typical lithographically patterned wavy interconnects.

Keywords: Stretchable electronics; conducting polymer; field-effect transistors; ionic dopant; patterning; plasticizer; polymer characterization; rigid-island; soft interface; transparent electrode.