Photopatternable, degradable, and performant polyimide network substrates for e-waste mitigation

Abstract

The continuous accumulation of electronic waste is reaching alarming levels, necessitating sustainable solutions to mitigate environmental concerns. Fabrication of commercial electronic substrates also requires wasteful high heat. To this end, we develop a series of reprocessible electronic substrates based on photopolymerizable polyimides containing degradable ester linkages. Five imide-containing diallyl monomers are synthesized from readily available feedstocks to produce high-quality substrates via rapid photopolymerization. Such materials possess exceptional thermal (thermal conductivity, K = 0.37-0.54 W m−1 K−1; degradation temperature, Td > 300 °C), dielectric (dielectric constant, Dk = 2.81-3.05; dielectric loss, Df < 0.024), and mechanical properties (Young's modulus, ∼50 MPa; ultimate elongation, dL/L0 > 5%) needed for flex electronic applications. We demonstrate mild depolymerization via transesterification reactions to recover and reuse the functional components.