DUFFY1 |
Modelling stress in gold
nanoparticles and cantilevers |
Type |
Theoretical |
#students |
|
Orientation |
Why is
the scientific problem of interest at all? The
properties of nanoparticles and nanocantilevers are very different from those of the bulk material, due to
the high surface to volume ratio of nanostructures. One example is the effect
of surface stress on nanostructures. Stress is induced near the surface of
all solids due to the lower coordination of the surface atoms. In bulk
crystals this surface stress has little effect on the properties but in
nanoscale particles the surface stress induces a finite stress in the centre
of the particle and the magnitude of this stress increases as the size of the
particle decreases. This effect can be investigated for spherical particles
using continuum elasticity theory but such a theory is not appropriate for
very small particles when the atomistic structure needs to be considered. |
How |
How is
the research going to shed light on the given problem?. We have
recently developed a method for calculating the local stress from molecular
dynamics simulations. Using this model we can calculate the stress in
particles of arbitrary shape, size and charge. We have applied this to
titania nanoparticles and found interesting behavior. |
What |
What is the specific
thing that the student will do, and how does it fit inside the overall
project? In this project we will study gold nanoparticles and
calculate the variation in the stress with nanoparticle diameter. We will
also model nanocantilevers with a range of surface terminations. It time
permits the effects of adsorbed molecules on the stress, and the resultant
bending, will be calculated which is relevant to the application of
cantilevers as sensors. |
Special Knowlegde |
|
Supervisor |
Dr Dorothy Duffy d.duffy@ucl.ac.uk |