Seeded Epitaxial Growth of Crystallizable Polymers Governed by Crystallization Temperatures

Seeded growth is generally regarded as an ambient-temperature, living crystallization-driven self-assembly (CDSA) approach of block copolymers (BCPs) with crystallizable cores, which is a powerful method in preparing one-dimensional (1D) or two-dimensional (2D) polymer nanomaterials with precise control over size and compositions. Generally, crystallographic matching is considered as a fundamental principle that determines the happening of epitaxial growth. However, crystallization temperature also plays a vital role in governing the seeded growth behavior, which is usually ignored in previous studies. Herein, the effect of crystallization temperatures on seeded epitaxial growth of different crystallizable polymer blends involving a homopolymer and a corresponding BCP is extensively explored. It has been shown that crystallographic matching is essentially required but not sufficient for successful epitaxial growth. Crystallization-temperature-dependent seeded growth demonstrates that the critical size of nuclei generated from a crystalline substrate dominates the occurrence of epitaxial growth. A smaller thickness of deposited crystals than that of the crystalline substrate is required for the happening of epitaxial growth. This important finding provides a theoretical basis for the design of complex polymer nanoparticles with distinct core compositions from an alternative view of crystallization temperatures using the CDSA approach.