Ian Wark Research Institute
ARC Special Research Centre
ARC Special Research Centre
Research Area: Physics, chemistry, surface engineering, soft
matter
Supervisors: Dr Craig
Priest, Dr Martin Brinkmann* and Stephan Herminghaus* (*Max-Planck
Institute for Dynamics and Self-Organization, Germany)
Description: Liquid crystals are well-known for their use in LCD
devices (especially flat screen displays), however they have significant
potential for use as powerful, autonomous sensors for harmful chemicals
or biological agents. The optical response observed on LCD televisions
is due to the crystal-like alignment of LC molecules, induced by surface
properties within the screen that can be switched by external electrical
fields. While many devices contain LCs as flat confined films,
supporting these films in open surface structures has the potential to
realise microfluidic sensors for a range of chemical and biological
species in liquid systems. However, several fundamental challenges
exist. The stability of these supported films will depend on their
wetting properties (capillarity), which may be influenced by the
molecular alignment itself.
This project will reveal how the internal crystal-like properties of
LCs influence how they spread over various surface geometries. The
knowledge developed during the course of this project will inform the
development of novel microfluidic sensors that are highly-sensitive,
portable, and require no power to operate.
Techniques
Photolithography
Wet and Deep Reactive Ion Etching
Polarisation microscopy
Atomic Force Microscopy
Wettability measurements
Microfluidics
References
1. Forsberg, P. S. H.; Priest, C.; Brinkmann, M.; Sedev, R.; Ralston,
J., Langmuir 2010, 26, 860.
2. Priest, C.; Albrecht, T. W. J.; Sedev, R.; Ralston, J., Langmuir
2009, 25, 5655.
3. Priest, C.; Sedev, R.; Ralston, J., Physical Review Letters, 2007,
99, 026103.
4. Guo, W.; Herminghaus, S.; Bahr, C., Langmuir 2008, 24, 8174-8180
5. Cadwell, K. D.; Lockwood, N. A.; Nellis, B. A.; Alf, M. E.; Willis,
C. R.; Abbott, N. L., Sensors and Actuators B: Chemical 2007, 128,
91-98.
