Living Crystallization-Driven Self-Assembly of Polymeric Amphiphiles: Low-Dispersity Fiber-like Micelles from Crystallizable Phosphonium-Capped Polycarbonate Homopolymers

Living crystallization-driven self-assembly (CDSA) is an ambient temperature-seeded growth method of increasing interest for the preparation of well-defined and structurally complex 1D and 2D core-shell nanoparticles from crystallizable block copolymer amphiphiles. Recent reports have demonstrated that crystallizable homopolymer amphiphiles also undergo living CDSA to yield 2D platelets, but this field is considerably less explored. Herein, we describe the living CDSA of poly(fluorene trimethylene carbonate) (PFTMC) homopolymers with a charged end group. Two homopolymers PFTMCn-[PPh2Me]I (n = 12, 23), each with a cationic phosphonium chain-end, were synthesized and studied. From these precursors, high-aspect-ratio, low-dispersity 1D micelles of controlled length with a rectangular crystalline PFTMC core were formed. In addition, more complex nanoparticles were prepared such as linear block comicelles, including examples with alternating fluorescent segments, and branched comicelles. Linear hybrid assemblies of negatively charged spherical SiO2 NPs on the positively charged surface of the 1D ribbons were also synthesized. In contrast to the 2D platelets formed from charge-capped homopolymers described in previous studies, the formation of 1D fiber-like assemblies in this work highlights the influence of the nature of the crystalline core on the observed micelle morphology.