Our research program lies at the crossroads of organic chemistry and materials science. Its focus is using light to control the structures and functions of molecular and nanomaterials for use in a wide range of potential applications including as optical filters and other optoelectronic devices, as controllable reagents and catalysts, in detection and imaging, and in drug-delivery. My students’ research has been featured in science and business magazines, in scientific journals, on TV or on-line video, on the radio, in local, Canadian and international news and in over 70 articles in international web sites on four continents. Our distinctive advantage is our ability to develop creative solutions to practical challenges by designing photoresponsive organic molecules and, when needed, combining them with nanoparticles to control the mechanical properties of materials, in detection and imaging, and to release small molecules.
Research highlights slideshow. Hover your cursor over the image to pause the show.
photoresponsive diarylethenes
Diarylethene chromophores undergo reversible ring-closing and ring-opening reactions when exposed to two different colours of light.
colour-changing compounds
Ultraviolet light converts dithienylethene chromophores from colourless to coloured forms. The colour depends on the conjugation.
colour-blended polymers
Mixed co-polymers of photoresponsive chromophores can be 'blended' to obtain a range of colours.
patterning with colour
Photoresponsive polymers can be patterned when cast as thin films and exposed through mask.
controlling structure & function
It is not just the colour that changes when diarylethenes are exposed to light. Other electronic and steric properties can be modulated.
for example
controlling catalysis & reactivity
Small molecule mimics of important enzyme cofactors can be modulated using light to control catalysis.
controlling polymer adhesives
Photo responsive polymers can be used to make a weak adhesive stronger when exposed to UV light.
controlling dry-adhesives
Changes in the electrostatic nature of photoresponsive chromophores can be used to alter the properties of dry-adhesives based on microstructures.
controlling bio-function
Photoresponsive compounds can reversibly induce paralysis in live worms when exposed to light.
'release & report’
The same light source triggers the release of small molecules and changes the colour of the chromophore.
we also use inorganic nanoparticles for release & imaging
photothermal effects
Gold nanoparticles convert light to heat to break bonds and release small molecules in live cells.
we use the same effect for other applications
For example, release singlet oxygen (a known therapeutic) and single strands of DNA.
unconverting lanthanide-doped nanoparticles
Several near infrared photons can be converted to UV, blue, red and green photons to trigger organic reactions.
encapsulated nanoparticles
Amphiphilic polymers wrap around nanoparticles and provide hydrophobic environments to trap organic chromophores in water.
other things we have researched are
the growth of crystalline biomaterials
The growth of kidney stones involves layer-by-layer networks.
macroscopic structure of kidney stones
Some stones have "shells" around them preventing the influx of water.
