ZHIM · Organoboron-Based Luminescent Nanomaterials via Crystallization-Driven Self-Assembly

Organoboron-Based Luminescent Nanomaterials via Crystallization-Driven Self-Assembly

The goals of the proposal were to synthesize luminescent block copolymers containing a polyferrocenylsilane (PFS) metalloblock and boron-functionalized fluorescent coil blocks, and to study their self-assembly into functional nanoscale materials. These polymers were successfully prepared via sequential anionic polymerization followed by efficient thiol-ene “click” reactions, and were found to readily self-assemble into nanoscale objects in selective solvents for the coil block. This allowed us to prepare luminescent cylinders and platelets, depending on the chain lengths of the constituent block copolymers. These materials were then used to prepare complex, functional nanoscale objects by low-cost solution processing. Highlights include: 1) The preparation of colour-tunable fluorescent multiblock micelles by solution self-assembly. These represent the first route to self-assembled nanoscale objects analogous to display pixels, yet are approximately 1/500,000th the size of those found in commercial HD displays. Specifically, we have found that the crystallization-driven self-assembly (CDSA) method provides an effective route for the nanosegregation of functional units within a micelle, allowing us to prepare cylindrical structures with segmented colour by sequential assembly of red, green and blue fluorescent polymers. Furthermore, it was found that by concurrent self-assembly, the colour of the micelle blocks could be tuned throughout the visible spectrum. This work was recently published (Nature Communications, 2014, 5:3372). 2) The preparation of tailored hierarchical micelle architectures in two dimensions. We recently explored the self-assembly of platelet-forming block copolymers, and have shown that CDSA can indeed operate in a living manner in 2D. This allowed us to form concentric lenticular micelles, as well as hybrid architectures composed of both cylindrical and platelet components resembling nanoscale arrows and spears. This work is currently in press (Nature Chemistry, 2014, 6, 893). The proposed transfer of knowledge objectives progressed well throughout the duration of the fellowship. Working in the Manners group, Dr. Hudson has gained significant experience in the areas of polymer synthesis, self-assembly, and characterization of nanoscale objects. Through the supervision of graduate students, Dr. Hudson has been able to transfer knowledge and skill sets to the students. Dr. Hudson participated in several national conferences in his home country of Canada (Canadian Society for Chemistry National Meetings), and established collaborative contacts within the EU that will be maintained in his future. The work completed during the course of this fellowship has made a significant impact on the field of block copolymer self-assembly. The discovery of being able to prepare tailored, functional nanoscale objects using low-cost methods and with high precision is expected to have long term influences in the field of polymer chemistry. As a measure of the impact of Dr. Hudson’s work, his research was highlighted in the widely circulated periodical Chemical & Engineering News (see (“Nanopixels of any Color” 2014, 92, 10). As a result of activities made possible by this fellowship, Dr. Hudson has obtained a faculty position at the University of British Columbia (Canada).

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