Regular dispersion of gold nanoparticles in a peptoid nanosheet
Surface enhanced Raman spectroscopy (SERS) is a technique that has the potential to make Raman spectroscopy the new industry standard for both qualitative and quantitative analysis. The signal amplification of SERS relies on the increased strength of the electromagnetic field between SERS active gold nanoparticles (AuNPs) in a two dimensional (2D) array due to plasmon resonance. Because of this dispersion dependent property of SERS, AuNP concentration and uniformity in 2D arrays are required for good quantitative measurements. Unfortunately, the only current methods available for creating SERS substrates fit for these measurements are bottom up construction methods, which are expensive and time consuming. In this study, we demonstrate the controlled synthesis of a new class of 2D AuNP arrays, in which the AuNPs are embedded peptoid nanosheets. These sheets were prepared in vials containing 5nm AuNPs, dissolved in toluene, and B28 peptoid, dissolved in water, by a tube rotator. Sheet synthesis was standardized through a series of tests that sought to optimize formation based on mixing duration and speed. Sheets were observed to be of relatively consistent size and color. If a self-assembly method is developed that allows for consistent AuNP concentration across the substrate it would greatly reduce both the time and funds required for producing good quantitative SERS substrates.