Degradable semiconducting polymers without long-range order for on-demand degradation of transient electronics

Abstract

Current understanding of molecular design principles for degradable imine-based polymer semiconductors is limited to semicrystalline polymer morphologies. Herein, we design and synthesize a new class of degradable, nanocrystalline semiconducting polymers based off of indacenodithiophene (IDT) units using less toxic methods compared to commonly-used Stille polycondensation. Through the lack of long-range order of the degradable IDT-based polymer films, we show that enhanced stretchability can be achieved while maintaining similar electronic performance to their degradable, semicrystalline diketopyrrolopyrrole (DPP)-based counterpart. Degradation studies by ultraviolet-visible spectroscopy, gel permeation chromatography, nuclear magnetic resonance spectroscopy, and quartz crystal microbalance reveal the IDT-based polymers degrade orders of magnitude faster than the semicrystalline DPP-based polymer (within hours in solution and within one week in the thin film). Moreover, the IDT-based polymers can be degraded in milder acidic conditions (0.1 M HCl) than those used for semicrystalline DPP-based polymers, resembling acidic environments in the human body and allowing for environmentally-friendlier conditions from synthesis to degradation. Our work strengthens our understanding of structure-degradation property relationships of polymer semiconductors and paves the way toward transient electronics with triggerable, on-demand degradation.