Powder charging surface electrical potentials

Figure 3. Vertical cross-section showing equipotential contours inside a conductive cylindrical silo containing a symmetric conical heap of uniformly charged solids. The electrostatic potential maximum exists on the center line somewhat below the powder surface, while the maximum electric field intensity occurs near the wall just above the powder.

Similar specific surface area of the powders (Table 2) but different zeta potential indicated that the nanoparticles could behave differently during formation of the nanocomposite fibres. Negatively charged TCP particles could be drawn out by electric field created between the needle and the collector which should improve distribution of the nanoparticles in the forming fibre. On the other hand, positively charged silica particles should be collected on the collectors needle which means higher inclination to agglomeration inside the fibre. 

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