On-nanoparticle monolayers as a solute-specific, solvent-like phase

In addition to modifying surface properties, self-assembled monolayers, SAMs, on nanoparticles can selectively incorporate small molecules from the surrounding solution. This selectivity has been used in the design of substrate-specific catalytic systems but its degree has not been quantified. This work uses catalytic centers embedded in on-nanoparticle hydrophobic SAMs to monitor and quantify the partitioning of molecules between the bulk solvent and these monolayers. A combination of experiments and theory allows us to relate the logarithm of the incorporation-into-SAM constant to the bulk log P values, characterizing the incoming substrates. These results are in line with classic, semi-empirical linear free energy relationships between partitioning solvent systems; in this way, they substantiate the view of nanoscopic on-particle SAMs acting akin to a bulk solvent phase.

Automated summary

In addition to modifying surface properties, self-assembled monolayers on nanoparticles can selectively incorporate small molecules from the surrounding solution. This study uses catalytic centers embedded in hydrophobic SAMs on nanoparticles to quantitatively analyze the partitioning of molecules between the bulk solvent and these monolayers. The results demonstrate that the incorporation-into-SAM constant can be related to the bulk log P values, supporting the idea that nanoscopic on-particle SAMs act like a bulk solvent phase.