Spray drying of colloidal dispersions containing ellipsoids

Area of Science:

• Materials Science
• Colloid Science

Background:

• Spray drying is a versatile method for producing micro-granules from colloidal dispersions.
• Understanding granule morphology is crucial for applications in various technological fields.
• The shape of constituent particles is hypothesized to influence micro-granule structure.

Purpose of the Study:

• To investigate the formation of micro-granules from nano-ellipsoid dispersions using spray drying.
• To quantitatively analyze the morphological features and ellipsoid packing within the granules.
• To study the micro-structure evolution and structural integrity of granules upon re-dispersion.

Main Methods:

• Controlled spray drying of nano-ellipsoid colloidal dispersions.
• Small Angle Neutron Scattering (SANS) and Small Angle X-ray Scattering (SAXS) for structural analysis.
• High-resolution Field Emission Scanning Electron Microscopy (FEG-SEM) for morphology.
• Re-dispersion studies to assess time evolution and structural integrity.

Main Results:

• Micro-granule morphology is strongly correlated with the aspect ratio of the constituent nano-ellipsoids.
• Low aspect ratio ellipsoids yield spherical granules.
• High aspect ratio ellipsoids result in varied morphologies, including doughnut-shaped granules.

Conclusions:

• The aspect ratio of ellipsoidal particles is a key determinant of micro-granule shape during spray drying.
• A mechanism for aspect ratio-dependent shape transformation is proposed.
• This finding offers control over micro-granule morphology for tailored applications.