Atomized Oxidative Polymerization as a 3D Printing Platform for Binder‐Free, Bulk Conductive Polymer Architectures

ABSTRACT Translating the ultrahigh intrinsic conductivity of conjugated polymers into bulk 3D architectures remains a formidable challenge due to the fundamental dichotomy between rheological printability and electronic purity. Existing strategies necessitate a compromise: solution‐processing requires insulating binders that degrade charge transport, while binder‐free vapor‐phase polymerization (VPP) is kinetically confined to surface‐limited thin films by diffusion constraints. Here, we introduce atomized oxidative polymerization (AOP), a manufacturing paradigm that overcomes these kinetic barriers via active, layer‐by‐layer monomer atomization. This approach ensures stoichiometric reaction conditions throughout the printed volume, driving a structural transition toward highly conductive quinoid‐dominant chains with enhanced π‐π stacking. The resulting binder‐free poly(3,4‐ethylenedioxythiophene) (PEDOT) structures achieve bulk conductivities exceeding 950 S/cm and superior mechanical stiffness, while uniquely exhibiting suppressed thermal transport characteristic of a phonon glass, effectively decoupling electrical and thermal transport. AOP establishes a generalizable platform for fabricating dense, insoluble conjugated polymer architectures for advanced applications, including high‐efficiency organic thermoelectrics, thermally stable biointerfaces, and energy storage devices, without the limitations of traditional solution or vapor‐phase processing.