title: Growth mechanisms of MgO nanocrystals via a sol-gel synthesis using different complexing agents.
abstract: In the preparation of nanostructured materials, it is important to optimize synthesis parameters in order to obtain the desired material. This work investigates the role of complexing agents, oxalic acid and tartaric acid, in the production of MgO nanocrystals. Results from simultaneous thermogravimetric analysis (STA) show that the two different synthesis routes yield precursors with different thermal profiles. It is found that the thermal profiles of the precursors can reveal the effects of crystal growth during thermal annealing. X-ray diffraction confirms that the final products are pure, single phase and of cubic shape. It is also found that complexing agents can affect the rate of crystal growth. The structures of the oxalic acid and tartaric acid as well as the complexation sites play very important roles in the formation of the nanocrystals. The complexing agents influence the rate of growth which affects the final crystallite size of the materials. Surprisingly, it is also found that oxalic acid and tartaric acid act as surfactants inhibiting crystal growth even at a high temperature of 950°C and a long annealing time of 36 h. The crystallite formation routes are proposed to be via linear and branched polymer networks due to the different structures of the complexing agents.
authors.affiliation: School of Chemistry and Environmental Studies, Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, Selangor 40450, Malaysia ; Centre for Nanomaterials Research, Institute of Science, Universiti Teknologi MARA, Level 3, Block C, Shah Alam, Selangor 40450, Malaysia.
authors.forename: Mohd Sufri
authors.initials: MS
authors.lastname: Mastuli
authors.affiliation: School of Physics and Materials Studies, Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, Selangor 40450, Malaysia ; Centre for Nanomaterials Research, Institute of Science, Universiti Teknologi MARA, Level 3, Block C, Shah Alam, Selangor 40450, Malaysia.
authors.forename: Norlida
authors.initials: N
authors.lastname: Kamarulzaman
authors.affiliation: School of Chemistry and Environmental Studies, Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, Selangor 40450, Malaysia.
authors.forename: Mohd Azizi
authors.initials: MA
authors.lastname: Nawawi
authors.affiliation: School of Physics and Materials Studies, Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, Selangor 40450, Malaysia ; Centre for Nanomaterials Research, Institute of Science, Universiti Teknologi MARA, Level 3, Block C, Shah Alam, Selangor 40450, Malaysia.
authors.forename: Annie Maria
authors.initials: AM
authors.lastname: Mahat
authors.affiliation: School of Physics and Materials Studies, Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, Selangor 40450, Malaysia ; Centre for Nanomaterials Research, Institute of Science, Universiti Teknologi MARA, Level 3, Block C, Shah Alam, Selangor 40450, Malaysia.
authors.forename: Roshidah
authors.initials: R
authors.lastname: Rusdi
authors.affiliation: Centre for Nanomaterials Research, Institute of Science, Universiti Teknologi MARA, Level 3, Block C, Shah Alam, Selangor 40450, Malaysia.
authors.forename: Norashikin
authors.initials: N
authors.lastname: Kamarudin
keywords: Complexing agent; Crystal growth; MgO; Nanostructured materials; Sol-gel process