Towards the development of solid-state platform optical sensors: aggregation of gold nanoparticles on polyurethane foam

In this paper, we report on a novel type of nanocomposites based on gold nanoparticles (AuNPs) and polyurethane foam (PUF), which represents an ability of AuNP aggregation on solid polymer matrix with the strongly different selectivity in comparison with aggregation of the same AuNPs in solution. This may indicate that a new type of aggregation takes place, which can be called solid-phase aggregation. A systematic study using diffuse reflectance spectroscopy revealed features of the solid-phase aggregation. The PUF-AuNPs nanocomposites can be synthesized by a simple and low cost procedure based on adsorption of different type AuNPs from aqueous solution onto PUF. Prospects of obtained composite materials for sensing some organic compounds using diffuse reflectance spectroscopy or colorimetry are shown. This nanocomposites have the increased selectivity to thiols allowing for their determination with limits of detection of 0.01-0.05μgmL-1 and relative standard deviations of 3-5%. Charged species that affect AuNPs in solution do not influence them on PUF.