Zeta potential measurement on lithium lanthanum titanate nanoceramics

• Zeta potential ζ, isoelectric point IEP and agglomeration of Li0.5La0.5TiO3 colloidal suspensions were studied.
• Zeta potential of Li0.5La0.5TiO3 varied from positive to negative with increasing pH from 2 to 8.
• Li0.5La0.5TiO3 suspensions reached the isoelectric point at pH range of 3–5.
• Li0.5La0.5TiO3 colloidal suspensions were stable in the pH range of 7.0–8.0.
• Li0.5La0.5TiO3 nanoparticles aggregated rapidly at ionic strengths >1 mmol/dm3.

The zeta potential, isoelectric point, and agglomeration of Li0.5La0.5TiO3 (LLTO) nanoparticles dispersed in aqueous media at different ionic strengths have been studied. The zeta potential was determined from electrophoretic mobility measurements, according to Smoluchowski's equation, for Li0.5La0.5TiO3 suspensions in NaCl and KCl electrolytes with ionic strengths of 1, 10, and 100 mmol/dm3. The isoelectric point (IEP), zeta potential (ζ), and the agglomeration were shown to strongly depend on the ionic strength of the Li0.5La0.5TiO3 aqueous colloidal suspension in both NaCl and KCl electrolytes, which allows the determination of the effects of environmental conditions for Li0.5La0.5TiO3 manipulation in aqueous colloidal systems. The suspensions of Li0.5La0.5TiO3 nanoparticles reach the IEP in the pH range of 3–5. The ζ of Li0.5La0.5TiO3 nanoparticles varied from positive to negative values with a pH increase, which allows for the control of the surface charge depending on the purpose. The pH range of 7–8 and an ionic strength ≤1 mmol/dm3 are recommended as the most suitable conditions for both the LLTO colloidal shaping techniques application and the LLTO-based nanocomposite formation.

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