Incorporating Gold Nanoparticles with Varying Diameters into Freely Floating Nanosheets via a Biphasic Monolayer Adsorption Assembly Mechanism.

Peptoid nanosheets are versatile two-dimensional nanomaterials that can form through the assembly and collapse of peptoid monolayers at fluid interfaces. The resulting material freely floats in water due to its hydrophilic exterior (which can be functionalized to bind targets of interest) and hydrophobic interior. The oil-water interface is a rich environment for nanosheet synthesis, as it allows for hydrophobic cargo dispersed in the oil phase to be incorporated into the nanosheet interior. In this work, we describe the synthesis and characterization of organic-inorganic hybrid nanosheets formed using octadecanethiol-functionalized gold nanoparticles with a wide range of particle diameters (∼10-80 nm) via this unique biphasic monolayer adsorption assembly and collapse mechanism at the toluene-water interface. We demonstrate through optical microscopy, atomic force microscopy, and scanning electron microscopy measurements that a range of particle sizes can be successfully embedded between two peptoid monolayers. The particles are arranged in a single patchy monolayer within the nanosheets. The findings presented here open the door for creating multifunctional hybrid peptoid nanosheets that not only bind targets of interest but also possess useful optical, electronic, catalytic, and/or magnetic properties.