Tom Dursch

Graduate Student, Ph.D. Program

University of Pennsylvania, Philadelphia, PA.
B.S. Chemical and Biomolecular Engineering, 2009

 

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Research Interests:

  • Equilibrium swelling and mechanical spectroscopy of polyelectrolyte hydrogels
  • Water-soluble drug uptake and transport in soft-contact-lens-material hydrogels
  • Ice-crystallization kinetics during fuel-cell cold-start

 

tdursch
“What are you lookin’ at?  These are Jersey lab goggles.”


tdursch@berkeley.edu

 

Radke Lab Home PageGroup MembersSeminarPublications

 

  • Water uptake and mechanical spectroscopy of polyelectrolyte hydrogels:

Hydrogels are cross-linked polymeric networks that readily imbibe water and swell without dissolving.  Because of their soft consistency, biocompatibility, and high water content, hydrogels are used in numerous biomedical and pharmaceutical applications, including: drug delivery, bioseparations, and soft contact lenses. The ability of hydrogels to undergo large reversible deformations in response to environmental changes has recently extended their application to include: soft robotics, biomimetics, and microfluidics. In all applications, effectiveness is dictated largely by hydrogel mechanical and transport properties which depend strongly on the equilibrium water uptake.  Accordingly, a defining hydrogel characteristic is the equilibrium water volume fraction, aaa.  We present a method to predict bbb of both HEMA-based and silicone-based SCL hydrogels that compares well with experiment.

 

  • Drug uptake/release in soft-contact-lens-material hydrogels:

Solute uptake/release in soft contact lenses is critical in designing optimal care-packaging solutions for wetting and disinfection, controlling ocular drug delivery, and mitigating lens fouling. In all applications, the extent of solute partitioning and rate of diffusion is regulated by solute and lens hydrophilicity and charge, solute size, and lens mesh size. In this work, we measure and quantitatively predict solute partition and diffusion coefficients in copolymer hydrogels where specific adsorption is pronounced. We employ two-photon confocal microscopy and back extraction with UV/Vis spectrophotometry. Partition and diffusion coefficients are obtained for small ionic and nonionic water-soluble drugs as functions of pH, hydrogel composition, and aqueous salinity. Partition and diffusion coefficients are predicted by accounting for hard-sphere size exclusion, Donnan electrostatic repulsion, and specific adsorption.

 

  • Ice-crystallization kinetics during fuel-cell cold-start:

In automotive applications, PEMFCs must permit rapid startup with minimal energy from subfreezing temperatures, known as cold-start. Under subfreezing conditions, water can solidify to form ice in the cathode, severely inhibiting cell performance and often causing cell failure. Despite significant attention in recent years, successful cold-start from sss °C remains a challenge. Elucidating the mechanisms and kinetics of ice formation within PEMFC-porous media, is therefore, critical to successful cell startup and high performance at low temperatures. In this work, we measure ice-crystallization kinetics within PEMFC-porous media. Experimental ice-nucleation rates and ice-crystallization kinetics are obtained using differential scanning calorimetry. For the first time, we develop predictive ice-crystallization rate expressions valid within PEMFC-porous media. Using a simplified PEMFC isothermal cold-start continuum model, we compare cell-failure time predicted using the newly obtained rate expression to that predicted using a traditional approach. From this comparison, we identify conditions under which including ice-crystallization kinetics is critical and elucidate the impact of freezing kinetics on low-temperature operation.

 

 

Publications:

  1. Dursch, T.J.; Trigub, G.J.; Liu, J.F.; Radke, C.J.; Weber, A.Z.; “Ice crystallization during cold-start of a proton-exchange-membrane fuel cell”, ECS Trans., 2013, accepted.
  2. Dursch, T.J.; Trigub, G.J.; Lujan, R.; Liu, J.F.; Mukundan, R.; Radke, C.J.; Weber, A.Z., “Ice-crystallization kinetics in the catalyst layer of proton-exchange-membrane fuel cell”, J. Electrochem. Soc., 2014, 161, F199-F207.
  3. Dursch, T.J.; Taylor, N.O.; Liu, D.E.; Wu, R.Y.; Prausnitz, J.M.; Radke, C.J.; “Water-soluble drug partitioning and adsorption in HEMA/MAA hydrogels”, Biomaterials, 2013, 35, 620-629.
  4. Dursch, T.J.; Trigub, G.J.; Liu, J.F.; Radke, C.J.; Weber, A.Z.; “Non-isothermal melting of ice in the gas-diffusion layer of a proton-exchange membrane fuel cell”, Int. J. Heat Mass Trans., 2013, 67, 896-901.\Dursch, T.J.; Ciontea, M.A.; Trigub, G.J.; Radke, C.J.; Weber, A.Z.; “Pseudo-isothermal ice-crystallization kinetics in the gas-diffusion layer of a fuel cell from differential scanning calorimetry (DSC)”, Int. J. Heat Mass Trans., 2013, 60, 450-458.
  5. Dursch, T.J.; Ciontea, M.A.; Trigub, G.J.; Radke, C.J.; Weber, A.Z.; “Isothermal ice-crystallization kinetics in the gas-diffusion layer of a proton-exchange-membrane fuel cell (PEMFC)”, Langmuir, 2012, 28, 1222-1234.
  6. Dursch, T.J.; Ciontea, M.A.; Trigub, G.J.; Radke, C.J.; Weber, A.Z.; “Ice-crystallization and water movement in gas-diffusion and catalyst layers”, ECS Transactions, 2012, 50, 429-435.
  7. Dursch, T.J.; Radke, C.J.; Weber, A.Z.; “Ice formation in gas-diffusion layers”, ECS Trans., 2010, 33, 1143-1150.

 

Presentations:

  1. Dursch, T.J.; Trigub, G.J.; Liu, J.F.; Radke, C.J.; Weber, A.Z., “Effect of external vibrations on non-isothermal ice-nucleation rates”, AIChE Annual Meeting, November 3-8th 2013, San Francisco, California.
  2. Dursch, T.J.; Trigub, G.J.; Liu, J.F.; Radke, C.J.; Weber, A.Z., “Ice crystallization during cold-start of a proton-exchange-membrane fuel cell”, 224th ECS Meeting, October 27th - November 1st 2013, San Francisco, California.
  3. Dursch, T.J.; Radke, C.J.; Weber, A.Z., “Phase change and water movement in fuel-cell porous media”, Symposium in honor of Massoud Kaviany’s 65th birthday, ASME Heat Transfer Conference, July 16th 2013, Minneapolis, Minnesota.
  4. Dursch, T.J.; Trigub, G.J.; Liu, J.F.; Radke, C.J.; Weber, A.Z., “Isothermal ice-crystallization kinetics in catalyst layers of proton-exchange-membrane fuel cells”, 87th Colloid and Surface Science Symposium, June 23-26th 2013, Riverside, California.
  5. Dursch, T.J.; Ciontea, M.A.; Trigub, G.J.; Radke, C.J.; Weber, A.Z., “Ice-crystallization kinetics and water movement in gas-diffusion and catalyst layers”, 220th ECS Meeting, October 7-12th 2012, Honolulu, Hawaii.
  6. Dursch, T.J.; Ciontea, M.A.; Trigub, G.J.; Radke, C.J.; Weber, A.Z., “Non-isothermal ice-crystallization kinetics in the gas-diffusion layer of a proton-exchange-membrane fuel cell (PEMFC)”, 86th Colloid and Surface Science Symposium, June 10-13th 2012, Baltimore, Maryland.
  7. Dursch, T.J.; Ciontea, M.A.; Radke, C.J.; Weber, A.Z., “Isothermal ice-crystallization kinetics in the gas-diffusion layer of a fuel cell, 85th Colloid and Surface Science Symposium, June 19-22nd 2011, Montreal, Quebec, Canada.
  8. Dursch, T.J.; Radke, C.J.; Weber, A.Z., “Ice formation in gas-diffusion layers”, 218th ECS Meeting, October 10-15th 2010, Las Vegas, Nevada.

 

 

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