Synthesis and Characterization of Peptoids and their Self-Assembly into Higher Ordered Nanosheet

Art conservation utilizes analytical techniques to determine resins, binders and organic pigments specifically used in paintings. However, where paint layers are too thin, surface enhanced Raman spectroscopy (SERS) provides unique advancements to the conservation field. SERS relies on well-ordered arrays of gold nanoparticles (AuNPs) to enhance signals provided by molecular vibrations. One strategy to assist 2D assembly of these nanoparticles is to use peptide-like molecules, known as peptoids. Unlike peptides, peptoids lack backbone chirality and H-bond donors which allows for their ability to self-assemble into secondary structures. Previous studies have shown that peptoid monolayers at fluid interfaces can serve as platforms to guide the 2D assembly of hydrophobic AuNPs into peptoid nanosheets. The peptoid nanosheets are promising candidates to use as SERS sensors that can bind to and detect select pigments and their degradation products with high sensitivity. This study focuses on the solid-phase synthesis of peptoid sequences that can assemble into composite AuNP nanosheets at the liquid-liquid interface. Liquid chromatography- mass spectrometry, optical microscopy, atomic force microscopy, and Raman spectroscopy were used to analyse peptoid formation and characterize the composite nanosheet films on solid substrates. Preliminary results have suggested that the synthesis of the amphiphilic peptoid sequence was successful. This sequence has the potential to assemble into nanosheets that can be used for pigment analysis.