Self-assembly of amphiphilic block copolymers can form a range of different nanostructures such as spherical micelles, vesicles and cylinders. Compared to lipid-based constructs, polymer nanostructures have greater potential for advanced chemical functionalization and physiological application due to their better stability and more expansive chemical modifications. Smart polymer nanostructures which respond to environmental stimuli such as pH, temperature, ultrasound, changes in chemical concentration and redox attracted much attention. Our group is especially interested in how this response can be tuned to change the function, size or morphology of the construct to allow for their application in a wide range of settings such as delivery vehicles or sensors. We have a number of projects in this research area including;
1. Developing a fundamental understanding of temperature responsive nanostructures
We have created a series of micelles as a model for assessing the effects that coronal chain confinement has on the thermoresponsive properties of micelles. By using a combination of complementary techniques, we found that for all the micelles in the series, the corona chains begin to collapse at temperatures far below the measured cloud points. In addition to this, the reversibility of the thermal phase transition was found to directly correlate to core hydrophobicity, and therefore the aggregation number of the construct. This new understanding is key the design and developement of novel responsive nanostructures.
2. Designing and syntheising new responsive constructs
Including the development of polymers and constructs that can reversibly respond to changes in hydrogen bonding, salt concentration and/or CO2. The synthesis of such multiblock copolymers allows for preparation of morphology switching nanostructures for materials with controlled release potential and also sensing applications.
Probing the causes of thermal hysteresis using tunable Nagg micelles with linear and brush-like thermoresponsive coronas, L. D. Blackman, M. I. Gibson, R. K. O'Reilly, Polym. Chem., 2016, DOI: 10.1039/C6PY01191H
Cyclic Graft Copolymer Unimolecular Micelles: Effects of Cyclization on Particle Morphology and Thermoresponsive Behavior, R. J. Williams, A. Pitto-Barry, N. Kirby, A. P. Dove, and R. K. O’Reilly, Macromolecules, 2016, 49, 2802–2813, DOI: 10.1021/acs.macromol.5b02710
The Effect of Micellization on the Thermoresponsive Behavior of Polymeric Assemblies, L.D. Blackman, D. B. Wright, M. P. Robin, M. I. Gibson, R.K.O'Reilly, ACS Macro Letters, 2015, 4, 1210-1214. DOI: 10.1021/acsmacrolett.5b00551
Tuning the aggregation behaviour of pH responsive micelles by copolymerization, D. B. Wright, J. P. Patterson, A. Pitto-Barry, P. Cotanda, C. Chassenieux, O. Colombani, and R. K. O’Reilly, Polymer Chemistry, 2015, 6, 2761-2768 DOI: 10.1039/C4PY01782J
One–pot synthesis of responsive sulfobetaine nanoparticles by RAFT polymerisation: the effect of branching on the UCST cloud point, H. Willcock, A. Lu, C.F Hansell, E. Chapman, I. Collins, R.K. O'Reilly, Polymer Chemistry, 2014, 5, 1023-1030, DOI: 10.1039/C3PY00998J
'Giant Surfactants' Created by the Fast and Efficient Functionalization of a DNA Tetrahedron with a Temperature-Responsive Polymer, T. Wilks, J. Bath, Jan de Vries, J. Raymond, A. Herrmann, A.J. Turberfield, R.K. O'Reilly, ACS Nano, 2013, 7, 8561-8572. DOI:10.1021/nn402642a