Advanced Polymers that Build Themselves – In Water!
Can we build the next generation of advanced materials from simple building blocks? Could we even get the materials to build themselves, and do it in water?
Using small molecular building blocks, we can use spontaneous self-assembling processes to build our advanced materials for us. Using a “molecular handcuff” molecule (cucurbit[n]urils, CB[n]s) to dynamically bind our building blocks together, we can achieve some really interesting structures with unique properties in a water environment.
CB[n]s are a series of molecules of different sizes that can bind very strongly to particular groups we can attach to a variety of molecules. These bonds are dynamic, and can be reversibly broken and reformed on demand. Previously these have been attached to polymers, and when combined with CB[n] it will result in hydrogel materials that have gone on to be applied in drug delivery.
By making the molecular building blocks consist of many branches, we can assemble highly branched networks that are tighter and more compact than linear systems. This can be taken a step further by capitalising on the selective binding of CB[n]s, so we can control whether our “supramolecular polymers” will form individually or cross-link into a gel. By also making our molecules responsive to certain stimulus, such as UV light, we can assemble and disassemble our systems on demand.
After designing our molecular-based systems we can then apply them to templated assembly. By taking tiny droplets of water as an emulsion, the formation of our polymer network can be assembled at the edge of the water droplets by using electrostatic charges, forming our extended supramolecular network at the interface. This has given us one of the first examples of a macroscopic, visible network assembled entirely from small molecules in water using CB[n] chemistry, which can then stabilise a water droplet in an emulsion.
However, many questions remain to be solved, and this is the focus of my PhD project. Can we form high molecular weight hyperbranched supramolecular polymers in an aqueous environment? Can we massively affect the viscosity of solutions using this approach?
Department of Chemistry
Cover Image- Goodphone