Peptoid Interactions with Self-Assembled Gold Nanosheets

Gold nanoparticles have the ability to self-assemble into two-dimensional sheet-like structures at air-liquid and liquid-liquid interfaces. These gold nanosheets, which are easy to detect based on their optical properties, have been used in applications such as sensing bacterial and chemical pollutants in water. In order for gold nanosheets to be effective in such applications, the assembly of the nanoparticles must be carefully controlled at air-liquid and liquid-liquid interfaces. This study explores using peptoids, a non-natural protein-like polymer, to direct the assembly of polystyrene functionalized gold nanoparticles at the toluene-water interface. Surface tension measurements of the gold nanoparticles, peptoid, and both together were obtained as a function of nanoparticle concentration and size to assess the degree of interaction between the peptoid and nanoparticles at the interface under varying conditions. The result of the addition of the peptoid to the nanoparticle is a decrease in surface tension, suggesting that the peptoid helps enhance assembly of nanoparticles at the toluene-water interface. Future studies will include the fabrication of gold nanosheets from the interfacial nanoparticle-peptoid assembly and attempting to stabilize these sheets using a photochemical cross linking strategy.