Timothy Murdoch

 
tmurdoch@seas.upenn.edu

M44 Towne Building
220 S. 33rd St., Philadelphia PA 19104

Google Scholar

Research Interests

In previous research I investigated the fundamental properties of nano-scale, responsive polymer brush coatings as a function of salt concentration and identity. These studies utilised a suite of surface-sensitive techniques including ellipsometry, atomic force microscopy (AFM), quartz crystal microbalance with dissipation monitoring (QCM-D), and neutron reflectometry (NR). Here the combination of techniques allows an insight into the behaviour of these brushes greater than the sum of its parts. I am currently utilising these techniques to understand why some commercial polymeric viscosity modifiers in engine oils exhibit a greater lubricating effect than expected based on their viscosity alone. These studies will allow the creation of better, multi-functional engine oil additives.

My broader research interests include:

  • Fundamental studies of advanced surface coatings
  • Experimental understanding of specific ion effects
  • Stimuli-responsive materials
  • Development of better analysis tools for fitting NR data

 

Education

Ph. D. in Chemical Engineering, University of Newcastle, Australia (2018)

Dissertation Title: Specific Ion Effects on Stimulus-Responsive Polymer Brushes

Supervisors: A/Prof. Grant Webber and Prof. Erica Wanless

B. E. (Hons.) in Mechanical Engineering / B. Sc. in Chemistry, University of Newcastle, Australia (2013)

 

Professional Experience

  • Postdoctoral Researcher (May 2018 – Present)
    University of Pennsylvania, Philadelphia PA

Awards and Scholarships

  1. Travel Bursary, International Association of Colloid and Research Science, 2015
  2. Post Graduate Research AwardAustralian Institute of Nuclear Science and Engineering, 2014-2017
  3. University Medal (B. E. Chemical), University of Newcastle, 2013

 

Peer-Reviewed Publications 

  1. Murdoch, T. J.; Humphreys, B. A.; Johnson, E. C.; Webber, G. B.; Wanless, E. J. Specific ion effects on thermoresponsive polymer brushes: Comparison to other architectures. J. Colloid and Interface Sci. 2018, 526, 429-450. DOI: 10.1016/j.jcis.2018.04.086
  2. Willott, J. D.; Murdoch, T*. J.; Leermakers, F. A. M.; de Vos, W. M. Behavior of Weak Polyelectrolyte Brushes in Mixed Salt Solutions. Macromolecules 2018, 51, 3, 1198-1206. DOI: 10.1021/acs.macromol.7b02244. *Co-lead author
  3. Murdoch, T. J.; Humphreys, B. A.; Johnson, E. C.; Prescott, S. W.; Nelson, A.; Wanless, E. J.; Webber, G. B. The role of copolymer composition on the specific ion and thermo-response of ethylene glycol-based brushes. Polymer 2018, 138, 229-241. DOI: 10.1016/j.polymer.2018.01.053.
  4. Murdoch, T. J.; Humphreys, B. A.; Willott, J. D.; Prescott, S. W.; Nelson, A.; Webber, G. B.; Wanless, E. J. Enhanced specific ion effects in ethylene glycol-based thermoresponsive polymer brushes. J. Colloid and Interface Sci. 2017, 490, 869-878. DOI: 10.1016/j.jcis.2016.11.044
  5. Willott, J. D.; Murdoch, T. J.; Webber, G. B.; Wanless, E. J. Physicochemical behaviour of cationic polyelectrolyte brushes. Prog. Polym. Sci. 2017, 64, 52-75. DOI: 10.1016/j.progpolymsci.2016.09.010
  6. Murdoch, T. J.; Willott, J. D.; de Vos, W. M.; Nelson, A.; Prescott, S. W.; Wanless, E. J.; Webber, G. B. Influence of Anion Hydrophilicity on the Conformation of a Hydrophobic Weak Polyelectrolyte Brush. Macromolecules 2016, 49, 9605-9617. DOI: 10.1021/acs.macromol.6b01897
  7. Murdoch, T. J.; Humphreys, B. A.; Willott, J. D.; Gregory, K. P.; Prescott, S. W.; Nelson, A.; Wanless, E. J.; Webber, G. B. Specific Anion Effects on the Internal Structure of a Poly(N-isopropylacrylamide) Brush. Macromolecules 2016, 49, 6050-6060. DOI: 10.1021/acs.macromol.6b01001
  8. Willott, J. D.; Murdoch, T. J.; Webber, G. B.; Wanless, E. J. Nature of the Specific Anion Response of a Hydrophobic Weak Polyelectrolyte Brush Revealed by AFM Force Measurements. Macromolecules 2016, 49, 2327-2338. DOI: 10.1021/acs.macromol.5b02656
  9. Humphreys, B. A.; Willott, J. D.; Murdoch, T. J.; Webber, G. B.; Wanless, E. J. Specific ion modulated thermoresponse of poly(N-isopropylacrylamide) brushes. Phys. Chem. Chem. Phys. 2016, 18, 6037-6046. DOI: 10.1039/C5CP07468A
  10. Willott, J. D.; Murdoch, T. J.; Humphreys, B. A.; Edmondson, S.; Wanless, E. J.; Webber, G. B. Anion-Specific Effects on the Behavior of pH-Sensitive Polybasic Brushes. Langmuir 2015, 31, 3707-3717. DOI: 10.1021/acs.langmuir.5b00116
  11. Abdelhamid, M. E.; Murdoch, T.; Greaves, T. L.; O’Mullane, A. P.; Snook, G. A. High-throughput approach for the identification of anilinium-based ionic liquids that are suitable for electropolymerisation. Phys. Chem. Chem. Phys. 2015, 17, 17967-17972. DOI: 10.1039/C5CP02294K
  12. Willott, J. D.; Humphreys, B. A.; Murdoch, T. J.; Edmondson, S.; Webber, G. B.; Wanless, E. J. Hydrophobic effects within the dynamic pH-response of polybasic tertiary amine methacrylate brushes. Phys. Chem. Chem. Phys. 2015, 17, 3880-3890. DOI: 10.1039/C4CP05292G
  13. Willott, J. D.; Murdoch, T. J.; Humphreys, B. A.; Edmondson, S.; Webber, G. B.; Wanless, E. J. Critical Salt Effects in the Swelling Behavior of a Weak Polybasic Brush. Langmuir 2014, 30, 1827-1836. DOI: 10.1021/la4047275
  14. Cheesman, B. T.; Smith, E. G.; Murdoch, T. J.; Guibert, C.; Webber, G. B.; Edmondson, S.; Wanless, E. J. Polyelectrolyte brush pH-response at the silica-aqueous solution interface: a kinetic and equilibrium investigation. Phys. Chem. Chem. Phys. 2013, 15, 14502-14510. DOI: 10.1039/C3CP52281D

Invited Talks               

  1. Murdoch, T. J.; Willott, J. D.; De Vos, W. M.; Nelson, A.; Prescott, S. W.; Wanless, E. J.; Webber, G. B. Modelling the Structure of polymer brushes using Neutron Reflectometry, Australian Soft Matter Scattering Workshop 2017, Sydney, Australia

Invited Non-Peer Reviewed Articles

  1. Murdoch, T. J.; Willott, J. D.; Humphreys, B. A.; Johnson, E. C.; Nelson, A.; Prescott, S. W.; Wanless, E. J.; Webber, G. B. New Approaches for Probing Structure-Stimulus Relations in Responsive Polymer Brushes. AINSE Annual Report: Research Highlights.