Table 1.

Characterization of bulk and nanoparticulate ZnO by scanning electron microscopy, dynamic light scattering, and zeta potential measurements^a

	Manufacturer's reported size (nm)	Morphology SEMb	Size by DLSc (nm), n = 3	Surface charge by zeta at pH ~8 (mV), n = 2
Bulk	-	Irregular	1920±151	−14.8±1.2
Alfa Aesar 44904	70	Irregular Angular	274±8	−18.5±1.2
Alfa Aesar 45409	40	Rounded	159±4	−21.6±3.7
Alfa Aesar 45588	70	Angular	179±3	−23.4±3.1
Consortium	25	Spheroid	215±15	−29.2±1.0

^aThe Alfa Aesar nanoparticles (NPs) were observed to have highly polydisperse size distributions by SEM and are, on average, the primary particle size reported by the manufacturer. Error in DLS and zeta potential values is the standard deviation of the mean values reported by the instrument. Additional analysis of all five particles by X-ray diffraction confirmed materials as ZnO (Zincite).

^bSEM = Scanning electron microscopy.

^cDLS = Dynamic light scattering.