This grant provides funding for a comprehensive study of a novel type of grafted miktoarm terpolymer system, which displays thermally responsive changes in their surface composition. Synthetic routes will be developed to produce miktoarm terpolymers with varying block arm lengths grafted onto both rigid and flexible substrates. The thermal behavior of these grafted terpolymer films will be evaluated using advanced experimental techniques and computational modeling. The behavior of these grafted terpolymers will be studied initially using blocks which would lead to reversible switching between hydrophilic or hydrophobic surfaces. The complex phase behaviour of the terpolymer is predicted to be both thermodynamically and kinetically controlled, consequently the phase behavior of these grafted terpolymer systems will be investigated and phase diagrams established as a function of relative arm molecular weights. The influence of chain dynamics on the equilibrium and non-equilibrium phase behavior will be investigated and hence the ability to predictably tune surface energies and therefore surface wetting critically evaluated. The effects of thermal gradients as well as localized annealing to control lateral wetting behavior of the terpolymer surface will be investigated. The effect of asymmetry of the relative arm lengths of the terpolymer on surface curvature and curvature inversion during temperature cycling will be studied in the second phase of the project.
Success within the project could have very wide implications in numerous technological applications where control of surface behaviour is important, including surface wetting and adhesion as well as phase inversion systems such as emulsions or vesicles. Surface curvature inversion that is predicted to occur for asymmetric terpolymers systems would have a defined time-dependent dynamic inversion behaviour which is controlled by the temperature. This could have important implications for smart surface applications such as drug delivery platforms, which could open up a new frontier of smart surface behavior.
