Structure and Rheological Behavior of Alkoxide-Based Precursors for Drawing of Metal Oxide Micro- and Nanofibres

The aim of this study is investigation of the influence of the method of metal alkoxy precursors preparation on their rheological characteristics and spinability for metal oxide fibre drawing. The precursor samples were obtained from tin 1-butoxide Sn(OBu)4 as a result of aqueous (AQ) and non-aqueous (NAQ) (thermolysis) treatment.

Small angle X-ray scattering (SAXS) data of precursors in the range of scattering vector modulus 0.07–5.3 nm-1 were recorded on a slit collimation camera KRM-1 by using Cu Kα radiation and NaI:Tl scintillation detector. Program system ATSAS [1] was used for calculation of the radius of gyration Rg and for 3D modeling of the cluster shape.

The rheological characterization of samples was conducted with a help of a rotational rheometer Mars II (Haake, Karlsruhe, Germany) equipped with plate-and-plate test geometry (plate diameter 20 mm). The precursors studied in this work consist of the elongated particles of 3 – 5 nm in length and 2 nm in diameter for both AQ and NAQ prepared precursors.

Rheological tests have proved that the solvent free precursors are typical non-Newtonian fluids. Precursors obtained with the help of NAQ treatment are more elastic as compared to those prepared with AQ procedure. Surface tension (ST) measurements show that the coefficient of ST of NAQ prepared precursor is 45% lower than that of AQ prepared one.

Fibres with aspect ratio up to 10000 and diameter of 200 nm were directly drawn from the NAQ precursors at room temperature in standard lab atmosphere. AQ prepared precursor allows obtaining of the fibers of minimum 500 nm in diameter with maximal aspect ratio 1000.