Constructing and decoding tree-ring-like surface patterns on self-assembled polymer platelets.

Precise control of surface patterns in assembled nanostructures remains a significant challenge in materials science. Here, we introduce a scalable bottom-up strategy utilizing living crystallization-driven self-assembly (CDSA) to fabricate tunable 3D surface patterns on polymer platelets. Inspired by biological growth increments, our approach leverages temperature-regulated, time-dependent crystallization to direct nanoscale organization, mimicking how nature constructs layered architectures. By exploiting polymer systems with temperature-dependent crystallization kinetics, we achieved diverse morphologies-including layered, concave, and convex features through controlled co-assembly and kinetic self-sorting. Temporal-thermal modulation was implemented in a continuous flow reactor, where precisely programmed residence times and temperature profiles enabled spatially resolved material deposition and growth history encoded in tree-ring-like patterns - control that is challenging or impossible to achieve using conventional batch methods. These features achieved lateral and vertical resolutions of ~73 nm and ~2 nm, respectively, allowing quantitative determination of directional crystallization rates (22.8 nm/s along the long axis and 13.4 nm/s along the short axis). Furthermore, modulating the number of layers provided a practical means to tune surface wettability. Our bioinspired design framework bridges synthetic self-assembly and natural structural logic, expanding opportunities for programmable materials in nanotechnology and functional systems.