Conductive polyurethane sponge modified with Gr/EC nanocomposite for high-performance pressure sensor

Polyurethane sponges with multilevel pore structure, high compressibility, and low modulus are promising materials for flexible sensors. However, achieving facile macroscopic assembly while implementing innovative interface engineering to address intrinsic non-conductivity and poor interfacial adhesion remains challenging. Herein, a generalized interface assembly strategy to overcome such a problem by engineering a graphene/ethyl cellulose-modified polyurethane sponge (Gr/EC@PS) consisting of nested structure and conductive skeleton is demonstrated. Benefiting from the hydrogen-bond interactions between purified skeleton surface and ethyl cellulose, as well as mechanical interlocking of graphene nanosheets within the sponge matrix, the sensing properties of the Gr/EC@PS pressure sensor are synergistically enhanced. Consequently, the optimized sensor not only delivers distinguished sensitivity of 3.83 kPa⁻¹ and rapid response/recovery time (80.6/124.0 ms) across broad pressure ranges, but also a long-duration stability (under 20 kPa pressure, cycling for 2000 times), surpassing most previously reported sponge-typed sensors. The as-proposed synergistic interface engineering approach establishes a novel paradigm for advancing flexible wearable electronics.