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The architecture of inorganic structures (on the microscopic to macroscopic length scale) has become one of the most important parameters that can be manipulated in order to optimize a structure for advanced applications. These structures are known to possess interesting and useful optical, electronic and/or magnetic properties that can subsequently be exploited in a wide variety of applications ranging from novel forms of catalysis to solar energy conversion. The choice of application is contingent on not only the chemical composition of the material but also on the overall morphology, and even more precisely on the accessible surface area. Currently, there are a myriad of methods available for fabrication of such intricate inorganic structures. However, irrespective of employing a certain fabrication method, the formation of well-organized materials is not trivial as various parameters have to be regulated. These include uniformity of size, stabilization against collapse, consistency in the chemical composition and growth of the overall structures with preferred morphology (thin films, spheres, fibers, helical spirals etc.).
The principal aim of the research in our lab has been to augment the current understanding of the concepts in supramolecular templating of inorganic materials for formation of nanostructures. To be more precise, self-assembling amphiphilic structures (e.g. synthetic or naturally occurring surfactants, peptides, and/or block co-polymers) in the presence of diffusion-controlling media (such as gels, microemulsions, non-aqueous solvents) are used to provide a temporary ‘scaffold’. This self-assembled template provides a complex 3-dimensionsal structure which has features on the nanometer length scale. Subsequently, colloidal inorganic building blocks (sol-gel precursors and/or nanoparticles), when introduced into this media, are then organized (ideally) into the inverse replica of the template. More importantly, this template, under appropriate conditions, is able to exploit the principles of molecular recognition and in turn structure-direct and size-constrain the condensing inorganic precursors. Interestingly, cooperative assembly imparts intricate morphological characteristics to the products that were previously unattainable.