Session: POLY/PMSE Poster Session:

Introduction of preselected functional units at the junction of block copolymers, while relatively unexplored in comparison to other polymer functionalisation methods, has been a valuable and efficient method for designing novel polymer architectures and stimuli-responsive systems. This is especially pertinent in the case of amphiphilic systems, where phase separation and self-assembly can create molecular thin layers of the stimuli-responsive unit, allowing for any physical/chemical alteration of the functional unit to have a profound effect on the entire polymeric system. Block copolymers with functional junctions have been applied to generate complex polymer architectures, as cleavable units for controlled release in supramolecular assemblies, improved electronic cascades in conductive polymers, and to alter diffusion properties of nanoassembly membranes. Our work involves the development, and study of, Donor-Acceptor Stenhouse Adducts (DASAs) at the junction of amphiphilic block copolymers. DASAs are a new class of photoswitches that DASAs undergo a reversible, coloured to colourless, linear to cyclic isomerisation under irradiation with visible light which is accompanied by a polarity switch from hydrophobic to hydrophilic. By establishing a modular synthesis strategy, we can incorporate DASAs into various block copolymer systems. Alternatively, employing hexafluoroisopropanol as a catalytic cosolvent allows us to form block copolymers through the DASA reaction itself. Future aims involve exploiting the tunable wavelength of absorption, polarity and conformational switching of DASAs in the junction of amphiphilic block copolymers in nanoscale assemblies such as polymersomes to afford novel controlled release systems and light-responsive nanoreactors/bioreactors, as well as to and probe the mechanophore potential of DASAs.

Javier Alaniz

Appearances