Halloysite Zeta-potential

Fig. 14.3 Zeta-potential of halloysite, and silica and alumina nanoparticles (for comparison).

During the formation of polycation-polyanion multilayer coatings on halloysite, we monitored the surface potential (electrokinetic zeta potential). Initially negative halloysite (—40 mV) was converted to a positive surface with polycation layer adsorption in the first step of the LbLassembly (figure 14.10). Adsorption of polyanions in the second step re-established the negative charge which was reversed... 

Fig. 14.10 Zeta-potential data for sequential deposition of polycations (PAH, PEI) and polyanions (PAA, PSS) on halloysite tubules, pH 6.5.

HaUoysite nanotnbes are ne tively charged (known from their zeta potential). The formation of P-phase in their composites with P VDF is ascribed to the electric interactions between the negatively charged snrface of halloysite and CH2 groups of the PVDE ... 

Schematic illustration of the fabrication of 2-mercaptobenzothiazole-loaded halloysite/polyelectrolyte nanocontainers. Right zeta potential data for sequential deposition of PAH and PSS polyelectrolytes on halloysite nanotubes, pH 7.5 (Shchukin et al., 2008). 

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