Hydrothermal synthesis of flower-like SnO2 particles consisting of single-crystalline nanorods through crystal growth in the presence of poly(acrylic acid)

We prepared crystalline SnO2 particles from aqueous solutions of SnCl4 containing poly(acrylic acid) (PAA) by hydrothermal treatment at 150 degrees C. The morphology of the SnO2 particles depended on the concentration of PAA and the pH value of the precursor solutions. The flower-like SnO2 particles of ca. 100 nm in diameter consisting of needle-like units ca. 50 nm in size were obtained from the solution of [SnCl4 center dot 5H(2)O] = 0.1 M and [PAA] = 0.02 M containing the acidic solvents of pH 0.35 via the hydrothermal treatment. The needle-like units were found to consist of nanorods of ca. 50 nm in length and ca. 5 nm in width. The flower-like SnO2 particles were thought to be formed through the moderate nucleation and growth rates that were provided by the relatively high solubility of the Sn4+ species under the acidic conditions and the their coordination by PAA.