Research on novel solar tracking methods using two polymer-based approaches was conducted. The first design for a solar tracking system with luminescent particles moving along polymer coatings is reported to provide the localized absorption of sunlight by phosphors which can follow the sun and hence provides a higher light intensity to be guided to a solar cell with higher efficiency. The second approach for realizing a polymer-based deformable lens on the surface of patterned ITO glass for light concentrating is reported. Both approaches rely on the application of spatially defined heating to a diluted polymer. These experiments were motivated by a) the well-known Rayleigh-Bénard convection flow within a fluid and b) Bénard-Marangoni flow effects concerning the movement of liquid along the surface of the fluid based on a surface tension gradient as a function of temperature.
In the first project, luminescent particles (YAG:Ce) are placed on the surface of a polymer film cast from a hot melt glue stick with a low melting point. When a heating wire 0.5 mm away from the top surface of the polymer film sample is transferred across the polymer, the floating YAG:Ce particles on the polymer surface can be pushed forward. In order to understand the mechanism of the particle movement, a laser-based measuring method was developed to view the surface profile of the melting polymer in situ. The melted glue stick polymer is observed to form a valley-like surface cross section that is able to transport YAG:Ce powder particles much like a surfer is carried forward on a wave. In the second project, a 0.25 mm thick polystyrene polymer containing a toluene solvent is cast on an ITO coated glass substrate with ITO stripe widths of 2, 6, and 10 mm. The heating source comprised of the ITO stripe can produce spatially selective heat when electric current is applied to thermally deform the cast polymer/solvent layer (polystyrene) on the substrate surface. After the deformation is complete an LED light source is used to determine the light concentration properties of the thermally formed lenses. The ITO stripe surface temperature profile was measured with a thermocouple and modelled with COMSOL Multiphysics software. The vaporization weight loss of solvent was also determined.
The optics of the LED light concentration was modelled by Optics Lab software. When the light emitted from the source passes through the thermally deformed polymer, focusing into two beams occurs in agreement with modelling results. / Thesis / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/18174 |
| Date | 11 1900 |
| Creators | Wang, Lei |
| Contributors | Kitai, Adrian, Materials Science and Engineering |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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