Graham Allegretto

Research Topic

Investigation and Applications of the Piezoionic Effect

Research Group

Molecular Mechatronics

Research Description

Polyacrylamide is a soft and transparent gel that belongs to a family of gels known as hydrogels. Hydrogels are extremely tough and elastic and can have water contents upwards of 90%. It has recently been discovered that by applying a pressure to a salt-water saturated hydrogel, a voltage can be generated. This effect, termed the “Piezoionic” effect, can potentially be used in tactile-sensors or as a way to generate electricity from mechanical energy. A similar response has also been observed for temperature gradients, possibly opening up a door towards a polymer-based thermoelectric generator or temperature sensor.

Due to its infancy, the mechanisms behind these effects are not yet fully understood and have yet to be thoroughly investigated. It is relatively agreed upon though that the voltages are arising from local imbalances between positive and negative ions, how and why this imbalance occurs is still up for debate. By varying the degree of polymerization of the hydrogel, the ions that are suspended in the gel, and utilizing tools such as Nuclear Magnetic Resonance (NMR) spectroscopy, the mystery of why an electric potential is being generated may finally be solved. Once a greater understanding of the mechanism has been obtained, its potential in energy harvesting, sensing, and various other applications will be investigated.

Why did you decide to study at UBC?

Being one of the best schools in Canada and close to home, it was an easy choice.


Why did you decide to pursue a graduate degree?

Having worked a few years in industry as an electrical engineer, I realised I wasn't happy in the career path that I had chosen. I was still interested in electrical engineering but not in the specialisation I found myself in. I started applying to different jobs, but the only offers I would get were more or less for the same job as what I was currently doing. I thought that a master's degree would not only provide skills I was lacking but also an opportunity to give academic life a try.

What aspects of your life or career before now have best prepared you for your UBC graduate program?

The few years I worked in industry provided me with organisational skills that have to proven to be invaluable for the program. I think the key to success in graduate school is having good organisational skills.

What do you like to do for fun or relaxation?

I play hockey and surf when I can. I also like to fish and play the guitar.

What advice do you have for new graduate students?

Attend everything you can, whether that's social outings or workshops provided by the school. A lot of people look at graduate school as a path to a degree but don't take the time to enjoy life while in school.