Department of Physics - Get Now DOC

							Department of Physics
& Atmospheric Science
Dalhousie University
Y2002/2003 Seminar Series

                "SEASHELL" IN-SITU
                         Or
  How To Design 3D Self-Assembled Nanoporous Shapes
                             Igor Yu. Sokolov
                  Department of Physics, Clarkson University

A creative combination of self-assembly and microfabrication may provide the
way to future nanotechnology because of its inherent simplicity, high reliability
and low cost of production. Recently the biomimetic synthesis of extraordinary
curved nanoporous silica shapes, such as rods, discoids, spheres, tubes and
hollow helicoids, obtained through the nucleation, growth and polymerization
of silicate liquid crystals, brings closer to reality the possibility of creating a
seashell in-situ, see an example of a mesoporous discoid in the figure below.




The ability to control curved shapes portends a variety of applications and new
technologies where mesostructure and geometry determine function. The
shapes are of great interest for a 3D spatial organization of nanosize wires,
quantum dots, and in micro-optics. It is possible to grow metallic nanowires
inside the pores using electroless plating, to put quantum dots inside by CVD,
etc.
In this study, I am analyzing the problem of morphogenesis of mesoporous
silica shapes and surface patterns. A theoretical basis will be outlined to
describe the variety of forms and surface designs that result from the liquid
crystal stage, silicification and rigidification of silicate liquid crystals. The main
factors that are responsible for shape formation will be described. A few
examples of numerical 3-D simulation are discussed to compare theory with
experiment and to project beyond the experimental results. Figure below shows
a few simulated examples of mesoporous shapes:




A new language of shapes may also emerge from this kind of research.



                      Friday April 4, 2003
                            2:30 pm
                           Room 135
                    Sir James Dunn Building