Faculty Sponsor's Department(s):
Flexible electronic devices are essential to the development of future technologies such as neural interfacing devices and wearable electronics. These technologies require materials that are conductive, but also soft and elastic enough to be compatible with biological systems. Considering the rigid nature of conventional conductive materials, these requirements present an obstacle in the development of stretchable electronics. A common method for addressing this problem involves blending rigid, conductive materials with soft, elastic materials. However, phase separation caused by the incompatibility of two materials with different chemistries presents a significant issue. In this work, we report a homogeneous polymer blend consisting of a conjugated polyelectrolyte (CPE) (a conductive polymer) and a bottlebrush polymer (a super-soft material) accomplished by utilizing polyelectrolyte complexation. Mixing solutions of the two materials resulted in the formation of a dense phase called coacervate, a swollen polymer mixture where two polymers complex strongly with each other via ionic crosslinking. Drying the coacervate leads to the formation of a solid polymer complex with desirable properties for uses in stretchable electronics. In particular, once doped, the complex had a conductivity of 0.4 S/cm. Preliminary results from shear and tensile tests indicate that the material is stretchable, elastic, and maintains its stretchability upon doping. Our study illustrates a novel pathway for engineering homogeneous polymer mixtures for flexible electronics, where mechanical elasticity and appreciable conductivity could both be achieved.