Leveraging Molecular Weight Dispersity for Scalable, Precise Synthesis of Nanocylinders Via Quasi-Polymerization-Induced Self-Assembly

The scalable and precise synthesis of polymeric nanostructures represents a significant challenge due to the inherent trade-off between production efficiency and morphological control. Here, we introduce a quasi-polymerization-induced self-assembly (quasi-PISA) strategy that integrates in situ nucleation-growth kinetics to fabricate uniform cylindrical micelles from liquid crystalline block copolymers at high concentrations (up to 10 wt.%). Counterintuitively, we demonstrate that the broad molecular weight distribution of PISA, often considered a drawback, can be harnessed as a key variable for precise assembly. By modulating polymerization conditions, fibril lengths were well controlled from 100 nm to over 3 µm (with length dispersity < 1.10) without requiring pre-formed seeds. This enables the one-pot synthesis of triblock comicelles and gram-scale production. Rheological analysis revealed a scaling relationship between solution viscosity and fibril length (η ∝ L^0.667). This work advances the scalable fabrication of length-controlled cylindrical nanostructures, offering design principles for their practical applications in diverse fields.