Mesoporous zirconia has attracted great research interest due to its unique properties such as high surface area, uniform pore size distribution, and large pore volume. Self-assembled structures have been used as directing agents to synthesize mesoporous zirconia. Here, we investigate the use of self-assembling block copolymers conjugated to cationic biomolecule lysozyme, as well as self-assembling cationic block copolymers as templates for synthesis of mesoporous zirconia in completely aqueous media. The synthesis of mesoporous zirconia in completely aqueous media with biomolecules will open up opportunities for different mechanisms for controlling zirconia synthesis. The inorganic content of the nanocomposite was determined by TGA, while the structure and composition of the samples was characterized by XRD, nitrogen adsorption, TEM, SEM, SANS, and solid state NMR. The results showed that zirconia nanocrystals formed after calcination of the as-synthesized nanocomposite at 500 �C, and significant crystal growth was observed only after 900 �C calcination. The conjugate-templated zirconia showed a surface area of 174 m2/g after calcination at 500 �C, and retained its tetragonal structure even after calcining at 900 �C. The cationic pentablock copolymer-templated zirconia showed a surface area of 191 m2/g, after calcination at 500 �C, and also demonstrated improved thermal stability. Several parameters such as pH, zirconium ion concentration, and calcination temperature were studied for the block copolymer-lysozyme conjugate template. We found that a more dilute precursor solution and high aging pH would lead to more thermally stable and smaller particles with higher surface area. The 500 �C calcinated zirconia with 0.08 M precursor had the highest surface area of 348 m2/g.

Aqueous phase synthesis and characterization of mesoporous zirconia templated by block copolymer and their bioconjugate micelles

245th National Meeting (2013)

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