Fig. 3

A UV–Vis spectra of mercaptoundecanoic acid coated AuNPs (dashed line) subsequently coated in (a) Polydiallyldimethylammonium chloride (PDADMAC) and (b) PDADMAC/polystyrenesulfonate (PSS). Reproduced from Ref. [61] with permission from Wiley. B Surface plasmon band shifts compared to the number of polyelectrolyte coatings on the AuNPs. Reproduced from Ref. [52] with permission from Wiley. C Zeta potential of uncoated citrate capped AuNPs (0) then subsequent addition of positively charged polyallylamine (PAA) and negatively charged polystyrenesulfonate (PSS). Reproduced and adapted from Ref. [52] with permission from Wiley