Electrospinning

Electrospinning is considered a simple top-down approach for the obtention of high aspect ratio nanofibers. Depending on process parameters such as applied voltage, tip-collector distance, type of polymer, solution conductivity and surrounding atmosphere, a great variety of morphologies have been obtained: dense fibers, tubes, beaded or strayed fibers and even tapes. This makes the technique potentially useful in many fields including biomedicine, surface finishing, electronics, sensors, ceramic reinforcement, smart textiles or electrical energy storage.
Furthermore, the possibility to deform and manipulate the flexible electrospun fibers adds even more value to this method. For instance, fiber alignment along different axis can be accomplished by suitable design of the electric field or through rotating drums.

Sketch of the electrospinning process.

On the other hand, chemical solution methodologies for obtaining functional oxides are powerful in reducing the annealing temperatures and allow nanostructuring following a self-assembling bottom-up approach. In particular, metalorganic decomposition (MOD) is gaining increased popularity as it uses metal carboxylates or β-diketonates as precursor salts which are less reactive towards water than alkoxides and can be dissolved in a large variety of solvents.

Optical image with as-spun precursor fibers.

The combination of electrospinning and chemical precursor solutions produces functional oxides with low dimensionality and high surface area. In electroceramics, this is specially interesting owing to the fact that electronic or ionic transport is constrained within the fibers, while very high specific surface is kept thus improving many practical performances depending on the interfacial electronic properties. To mention interesting applications in this respect, electrospinning has been applied to gas sensors , photocatalysts or magnetic sensors .
OXOLUTIA SL is interested in developing new materials and applications based on this combination.

FESEM image of as-spun precursor  fibers of CoFe₂O₄