Enhancing the scalability of crystallization-driven self-assembly using flow reactors

Anisotropic materials have garnered significant attention due to their potential applications in cargo delivery, surface modification, and composite reinforcement. Crystallization-driven self-assembly (CDSA) is a practical way to access anisotropic structures, such as 2D platelets. Living CDSA, where platelets are formed by using seed particles, allows the platelet size to be well controlled. Nonetheless, the current method of platelet preparation is restricted to low concentrations and small scales, resulting in inefficient production, which hampers its potential for commercial applications. To address this limitation, continuous flow reactors were employed to improve the production efficiency. Flow platforms ensure consistent product quality by maintaining the same parameters throughout the process, circumventing batch-to-batch variations and discrepancies observed during scale-up. In this study, we present the first demonstration of living CDSA performed within flow reactors. A continuous flow system was established, and the epitaxial growth of platelets was initially conducted to study the influence of flow parameters such as temperature, residence time, and flow rate on the morphology of platelets. Comparison of different epitaxial growth manners of seeds and platelets was made when using seeds to perform living CDSA. Size-controllable platelets from seeds can be obtained from a series flow system by easily tuning flow rates. Additionally, uniform platelets were continuously collected, exhibiting improved size and dispersity compared to those obtained in batch reactions

Real-time label-free imaging of living crystallization-driven self-assembly

The living crystallization-driven self-assembly (CDSA) of semicrystalline block copolymers is a powerful method for the bottom-up construction of uniform polymer microstructures with complex hierarchies. Improving our ability to engineer such complex particles demands a better understanding of precisely how to control the self-assembly process. Here, we apply interferometric scattering microscopy (iSCAT) to deliver real-time observation of individual poly(caprolactone)-based platelet growth. This label-free method enables us to map the role of key reaction parameters on platelet growth rate, size, and morphology. Furthermore, iSCAT provides a contrast mechanism for studying multi-layer platelets, offering new insights into the distribution of polymer compositions within a single platelet