Colour-tuneable nano-scale micelles
Block copolymers are a special type of polymer made up of blocks of two or more different repeating monomers. For example, if A and B are the individual monomers, AAABBBAAA could be a potential block copolymer formed by their covalent bonding. The combination, analogous to composites, builds on the individual properties of the components to yield something superior to their simple additive effects. With EU support of the project 'Organoboron-based luminescent nanomaterials via crystallization-driven self-assembly' (ZHIM), scientists conducted pioneering work on self-assembly of nano-scale micelle architectures from special block copolymers obtained with simple and low-cost methods. The results promise to revolutionise fields including high-definition displays and biomedical imaging and diagnostics. The team demonstrated for the first time self-assembly of nano-scale objects similar to display pixels but a half a million times smaller. Nano-segregation of functional units within a micelle produced segmented colour with sequential assembly of red, green and blue fluorescent polymers. They also produced tailored 2D architectures similar to blood platelets and used them to form hybrid architectures resembling nano-scale arrows and spears. Results have been published in the prestigious peer-reviewed scientific journals Nature Communications and Nature Chemistry, respectively. They were also highlighted in the periodical Chemical & Engineering News. Specifically, using polyferrocenylsilane metalloblock and boron-functionalised fluorescent coil blocks, block copolymers were produced via sequential anionic polymerisation followed by efficient click reactions. Click chemistry refers to reactions that are efficient, simple to perform, high yielding, and compatible with numerous solvents and functional groups. The block copolymers self-assembled into functional nano-scale luminescent cylinders and platelets by low-cost solution processing, namely crystallisation-driven self-assembly. The discovery of a route to tailored and functional luminescent nano-scale objects via simple and low-cost methods is expected to have lasting impact on polymer chemistry. In turn, rapid and inexpensive production of novel nano-scale architectures will lead to numerous applications of societal and economic importance in fields such as display technologies and biomedicine.
