Dr Daniel Toolan


Department: Chemical and Biological Engineering

Group: Dr Jonathan Howse

Status: Postdoctoral Researcher

Email: d.toolan@sheffield.ac.uk


During my PhD I developed the technique of stroboscopic microscopy, this technique allows direct imaging during spin-coating, allowing us to directly observe, in real-time, self-assembly processes (such as, phase-separation, phase coarsening, agglomeration, stratification etc…) at the microscale. I have used this technique to study topographical, compositional and crystalline development in spin-coated polymer blends. Further, I have studied the ordering of colloids, which has allowed the identificatio several key mechanisms governing the formation of colloidal crystals.

I am currently working on a project aiming to develop a synthetic pH switch through incorporation of enzymes within microparticles. Such enzyme-microparticles have technological applications in bio-sensors, bio-fuel cells or bio-refineries for complex chemical transformations. This work aims to synthetically replicate biological processes, such as frog oocytes maturation, synchronisation of activity in bacteria (quorum sensing) and cellular aggregation in slime mould, which all require a rapid transition from one state to another following a supercritical stimulus. These kinetically-controlled cell switches are driven by feedback such as autocatalysis, when a reaction is catalysed by its product.

Research Interests

• Microscopy

• Scattering

• Reflectivity

• Self-assembly

• Polymer blends

• Colloidal crystals

• Polymer brushes

Recent Publications

1. Daniel T. W. Toolan, Syuji Fujii, Stephen J. Ebbens, Yoshinobu Nakamura, Jonathan R. Howse. On the mechanisms of colloidal self-assembly during spin-coating. Soft Matter (2014). DOI: 10.1039/C4SM01711K

2. Ehtsham Ul Haq, Daniel T. W. Toolan, Jillian A. Emerson, Thomas H. Epps III, Jonathan R. Howse, Alan D. F. Dunbar and Stephen J. Ebbens. Real time laser interference microscopy for bar-spread polystyrene/poly(methyl methacrylate) blends. Journal of Polymer Science Part B: Polymer Physics (2014). DOI: 10.1002/polb.23513

3. Daniel T. W. Toolan, Richard Hodgkinson, Jonathan R. Howse. Stroboscopic Microscopy – Direct Imaging of Structure Development and Phase Separation During Spin-Coating. Journal of Polymer Science Part B: Polymer Physics (2013). 52 (1), 17-25.

4. Daniel T.W. Toolan, Nikki Pullan, Michael J. Harvey, Paul D. Topham, Jonathan R. Howse. In Situ studies of Phase Separation and Crystallization Directed by Marangoni Instabilities during spin-coating. Advanced Materials (2013), 25 (48), 7033-7037.

5. Jillian A. Emerson, Daniel T. W. Toolan, Jonathan R. Howse, Eric M. Furst, Thomas H. Epps, III. Determination of Solvent−Polymer and Polymer−Polymer Flory− Huggins Interaction Parameters for Poly(3-hexylthiophene) via Solvent Vapor Swelling. Macromolecules (2013). 46(16), 6533-6540.

6. Paul D. Topham, Andrew Glidle, Daniel T. W. Toolan, Michael P. Weir, Maximillian Skoda, Robert Barker, Jonathan R. Howse. The relationship between charge density and polyelectrolyte brush profile using simultaneous neutron reflectivity and in situ total internal reflection FTIR. Langmuir (2013). 29(20), 6068-6076.

7. Daniel T. W. Toolan, Ehtsham ul Haq, Alan Dunbar, Stephen Ebbens, Nigel Clarke, Paul D. Topham, Jonathan R. Howse. Direct Observation of morphological development during the spin-coating of polystyrene-poly(methyl methacrylate) polymer blends. Journal of Polymer Science Part B: Polymer Physics (2013), 51(11), 875-881.

8. Daniel T. W. Toolan, Andrew J. Parnell, Paul D. Topham, Jonathan R. Howse. Directed phase separation of PFO:PS blends during spin-coating using feedback controlled in situ stroboscopic fluorescence microscopy. Journal of Materials Chemistry A (2013), 1, 3587-3592.

9. Daniel T. W. Toolan, Jonathan R. Howse.* Development of in situ studies of spin coated polymer films. Journal of Materials Chemistry A (2013), 1, 603-616