PROBING THE FUNDAMENTAL FORCES OF GOLD NANOPARTICLES INTERACTING THROUGH NON-COVALENT QUADRUPLE HYDROGEN BONDING

Abstract

The strong dimerization, high selectivity, and directionality of self-complementary 2-ureido-4-pyrimidone (UPy) groups can lead to the formation of novel organic-inorganic hybrid nanostructure assemblies and provide a deeper understanding into the role of hydrogen bonding (HB) on programmable self-assembly at the nanoscale. The present work focuses on probing quadruple hydrogen bonding (QHB) ligand-ligand interactions between AuNPs through quartz crystal microbalance with dissipation monitoring (QCM-D), comparing these to Van der Waals (VdW) forces between NPs. Several NP functionalization combinations using UPy-containing ligands and ligands with no specific interacting groups (mPEG) are used in a sequence of experiments that provide the means for a quantitative comparison between Van der Waals forces and QHB interactions in nanoparticles. Our results show comparable degrees of interaction between QHB and VdW interactions, with trends that suggest that QHB between AuNPs are slightly stronger as seen through changes in frequency and changes in energy dissipation data.