Phototriggered Depolymerization of Flexible Poly(phthalaldehyde) Substrates by Integrated Organic Light-Emitting Diodes

We demonstrate phototriggered depolymerization of a low ceiling temperature ( T_c) polymer, poly(phthalaldehyde) (PPHA), via internal light emission from integrated organic light-emitting diodes (OLEDs) fabricated directly on flexible PPHA substrates with silver nanowire electrodes. The depolymerization of the PPHA substrates is triggered by absorption of the OLED emission by a sensitizer that activates a photoacid generator via energetically favorable electron transfer. We confirm with Fourier-transform infrared spectroscopy that the photon doses delivered by the integrated OLED are sufficient to depolymerize the PPHA substrates. We determine this critical dosage by measuring the operating lifetimes of the OLEDs whose failure is believed to be due to significant mechanical softening during the liquefaction of decomposed phthalaldehyde monomers.