Additive Manufacturing of Ordered Polymer Nanostructures.

Additive manufacturing (3D printing) allows the fabrication of complex 3D geometries, yet the integration of long-range ordered nanostructures within printed materials remains a fundamental challenge. In vat photopolymerization, rapid crosslinking kinetics typically arrest block copolymers in kinetically trapped, disordered morphologies. Here, we introduce Polymerization-Induced Arrangement of Nanostructures with Order-tunability (PIANO), a strategy that overcomes this kinetic mismatch by decoupling nanoscale ordering from network formation. PIANO utilizes a mobility mediator, ethylene glycol, to enhance polymer chain mobility, enabling rapid in situ ordering, while maintaining a hydrogen-bonding network capable of sustaining 3D printing stresses. This approach yields tunable lamellar and hexagonally packed cylindrical morphologies with domain spacings of 20-60 nm. Furthermore, ethylene glycol acts as a latent crosslinker during post-printing annealing, locking the ordered nanostructure while enhancing macroscopic mechanical strength. By reconciling the divergent timescales of molecular self-assembly and additive manufacturing, this strategy provides a robust platform for the hierarchical design of functional systems.