Open Positions with the Pojman Research Team

 

1) Studying Effective Interfacial Tension between Miscible Fluids

This NSF-supported project involves studying the transient but real interfacial tension between miscible fluids. We use spinning drop tensiometry, optical methods to study diffusion and microfluidics.

Graduate students and undergraduates are needed.

Pojman, J. A.; Whitmore, C.; Turco Liveri, M. L.; Lombardo, R.; Marszalek, J.; Parker, R.; Zoltowski, B. "Evidence for the Existence of an Effective Interfacial Tension between Miscible Fluids: Isobutyric Acid-Water and 1-Butanol-Water in a Spinning-Drop Tensiometer," Langmuir 2006, 22, 2569-2577.

Zoltowski, B.; Chekanov, Y.; Masere, J.; Pojman, J. A.; Volpert, V. "Evidence for the Existence of an Effective Interfacial Tension between Miscible Fluids. 2. Dodecyl Acrylate-Poly(Dodecyl Acrylate) in a Spinning Drop Tensiometer," Langmuir 2007, 23, 5522-5531.

 

2) Frontal Polymerization

Frontal polymerization is process in which a localized reaction spreads through an unstirred system because of the coupling of thermal diffusion and the Arrhenius dependence of the rate of an exothermic polymerization.

Click here for more information on the process.

We are attempting to develop commercially-useful systems for rapid repair of composites, autoclaveless curing of composites and novel methods of coating and preserving wood. We are collaborating with Professor Wu in Renewable Natural Resources.

 

Undergraduates and graduate students are sought.

 

3)Microencapsulation of reactive components for polymerization.

We encapsulate catalysts and initiators for polymerization in order to control the time when polymerization occurs.

Undergraduates and graduate students are sought.

McFarland, B.; Popwell, S.; Pojman, J. A. "Free-Radical Frontal Polymerization with a Microencapsulated Initiator," Macromolecules 2004, 37, 6670 - 6672.McFarland, B.; Popwell, S.; Pojman, J. A. "Free-Radical Frontal Polymerization with a Microencapsulated Initiator: Characterization of Microcapsules and Their Effect on Pot Life, Front Velocity and Mechanical Properties," Macromolecules 2006, 39, 53-63.

 

4) Control of Microparticle and Microcapsule size distribution.

Microencapsulation is usually performed in an oil-in-water process. Capsules are formed by an interfacial polymerization between an organic phase and a component in the aqueous phase. The size of the capsules is a function of the stirring rate and type of surfactant used. However, usually the particle size distribution is very broad. We are working with Professor Knopf in Chemical Engineering who has designed a special reactor that allows control of particle size. The reactor has an oscillating membrane. We will characterize the size and shape of the particles as a function of the amplitude and frequency of the vibrations and the type and concentration of the surfactants.

We will test different methods of encapsulation to determine if we can achieve narrow size distributions.

 

Undergraduates and graduate students are sought.