Figure 2.

Change in the electrokinetic potential of SPIONs with increasing surface coverage of polyacids CA, HA, PAM, PAA and GA, measured at pH ∼ 6–6.5 and 0.01 M NaCl. (CA, citric acid; HA, humic acid; PAA, poly(acrylic acid); PAM, poly(acrylic-co-maleic acid); the amount of the macromolecular polyacids (HA, PAA and PAM) was related to the moles of their carboxylic groups. The error in the relative values of zeta potentials is ±0.1 mV.) Reproduced with permission from [24] under CC-BY. The inset photo shows the colloidal stability of a series of SPION dispersions with increasing HA concentration. (Online version in colour.)