Gold nanoparticle-PPE constructs as biomolecular material mimics: understanding the electrostatic and hydrophobic interactions

Eleven cationic, monolayer-protected quaternary ammonium-functionalized gold nanoparticles (ANPs) were prepared and investigated for their ability to quench the fluorescence of a poly(p-phenyleneethynylene) (PPE) that features carboxylate groups to enable electrostatic interactions with the ANPs. Depending upon their structures, the ANPs displayed binding constants to the PPE from 8 × 107 to 1010 M−1, with particularly high affinity observed with aromatic functionalized ANPs capable of aromatic stacking. These binding constants were obtained by analyzing the quenching data using a modified Stern–Volmer formalism.