Gang Zhang

Fe/Co bimetallic regulation enables high‐performance microwave absorbers, yet the role of intrinsic coordination disparity in precursor conversion, nonequilibrium phase evolution, and cross‐band loss redistribution remains unclear. We design a poly(arylene sulfide sulfone) (PASS)‐predefined O/S heterogeneous donor‐field strategy to direct competitive–cooperative nonequilibrium phase evolution in Fe/Co systems. Covalently embedded sulfone‐O and thioether‐S sites, with PASS's rigid backbone, create a molecularly preorganized donor field that amplifies non‐equivalent Fe/Co coordination, promoting competitive bonding, differentiated phase pathways, and electronic‐state reconstruction during confined pyrolysis. Fe/Co regulation thus reshapes local phases, O/S chemical environments, and interfacial charge states via Fe─O/Co─S coordination preferences, generating multiphase heterostructures, amorphous/crystalline interfaces, defects, and lattice strain while balancing dielectric polarization, conductive transport, magnetic response, and impedance matching. The resulting CFC absorber achieves cross‐band absorption in low‐frequency 5G and high‐frequency radar bands. CFC‐4 exhibits −73.83 dB at 6.23 GHz (3.20 mm) and −76.59 dB at 16.98 GHz (1.31 mm), with a maximum EAB of 5.03 GHz. CFC‐4∼6 (1–5 mm) show >90% cumulative effective absorption over 2–18 GHz. Finite‐element simulations reveal a maximum RCS reduction of 42.5 dB on PEC. This work establishes O/S donor‐field engineering as a viable route to amplify Fe/Co coordination differentiation for efficient cross‐band microwave absorption.

Commodity polymers are ubiquitous in our society, having replaced many inorganic and metal-based materials due to their versatile properties. However, their functionality heavily relies on the addition of various components known as additives, making it challenging to recycle the polymer fraction of plastic materials effectively. Thus, it is crucial to develop efficient chemical recovery strategies for commodity polymers and additives to facilitate the direct utilization of recovered monomers and additives without additional purification. Here, we develop a strategy for co-upcycling two types of waste commodity polymers, polycarbonate, and polyethylene terephthalate into polyarylate, a high-performance transparent engineering plastic. By incorporating a highly active metal-free ionic liquids catalyst for methanolysis and a two-stage interface polymerization technique with variable temperature control, we successfully prepare polyacrylate film materials from real end-of-life plastics with direct utilization of capping agent impurities in recovered monomers. These materials exhibit excellent thermal performance (Tg = 192.8 °C), transmittance (reach up to 86.73%), and flame-retardant properties (V-0, UL-94), equivalent to those of commercial polyarylate (U-100, about $10000/ton), and could be further easily close-loop recycled. Demonstrated in kilogram-scale experiments and life cycle assessments, this approach offers a low-carbon, environmentally friendly, and economically feasible pathway for upcycling waste commodity polymers.