Morphogenesis of microshapes

Increasing interest in nanotechnologies and biocomplexity has created the need in understanding the morphogenesis of complex self-assembled shapes, which either exist in nature or can be synthesized for a specific purpose. These shapes can be the parts for micro electrical/optical machines, microtubules in the cell skeletons, seashells, etc. Liquid crystal templating of hexagonal mesostructured silica (known, for example, as MCM-41) brings a unique example of a material due to the following reason. This is already of great interest to industry because of its nanosize highly uniform porosity, and consequently, can be functionalized by putting various substances inside the pores. Secondly, the material has a relatively simple molecular structure; hence, the chemistry is relatively well understood. And finally, it is a good test system to study the morphogenesis due to the complex micron size shape of the mesoporous silicas. If the mesoscale synthesis is relatively well elaborated, the basic mechanism responsible for the overall morphogenesis of silica mesoporous shapes is not understood.

Main goal:
To elaborate quantitative theory of morphogenesis of mesoporous silica shapes, to develop experimental recipes of synthesis of specific shapes in a controlled way, to predict and synthesize new shapes, and to indicate a way to extend the proposed approach to complex biological systems.

Present Status and Preliminary Results:
There are only a few basic ideas how to attack this problem quantitatively [1,2]. The basic hypothesis is that the complex morphology of the shapes is a result of relaxation of mechanical stresses which appeared due to differential polymerization of silica precursor. Such a difference in the polymerization is expected to occur, e.g., due to the change of the environment during the synthesis, or because of the older inner parts of the shapes vs. the younger outer layers.
         Some experimentally observed shapes and corresponding computer 3D similations are shown below:



The other task is to find the condition of the synthesis to assemble the shapes with the same morphology. An example of assemble of a rather monodispersed fibers is shown below (unpublished). click on the picture to see the details

Other shapes zoo (click on each image to enlarge):

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