Fabrication of Thorny Au Nanostructures on Polyaniline Surfaces for Sensitive Surface-Enhanced Raman Spectroscopy

• Published in: ACS applied materials & interfaces 2013-01, Vol.5 (1), p.49-54
• Main Authors: Li, Siwei, Xu, Ping, Ren, Ziqiu, Zhang, Bin, Du, Yunchen, Han, Xijiang, Mack, Nathan H, Wang, Hsing-Lin
• Format: Article
• Language: English
• Subjects: Aniline Compounds - chemistry; Benzoates - chemistry; Gold - chemistry; Metal Nanoparticles - chemistry; Povidone - chemistry; Rhodamines - chemistry; Spectrum Analysis, Raman; Sulfhydryl Compounds - chemistry
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/am301881q

Here we demonstrate, for the first time, the fabrication of Au nanostructures on polyaniline (PANI) membrane surfaces for surface enhanced Raman spectroscopy (SERS) applications, through a direct chemical reduction by PANI. Introduction of acids into the HAuCl4 solution leads to homogeneous Au structures on the PANI surfaces, which show only sub-ppm detection levels toward the target analyte, 4-mercaptobenzoic acid (4-MBA), because of limited surface area and lack of surface roughness. Thorny Au nanostructures can be obtained through controlled reaction conditions and the addition of a capping agent poly (vinyl pyrrolidone) (PVP) in the HAuCl4 solution and the temperature kept at 80 °C in an oven. Those thorny Au nanostructures, with higher surface areas and unique geometric feature, show a SERS detection sensitivity of 1 × 10–9 M (sub-ppb level) toward two different analyte molecules, 4-MBA and Rhodamine B, demonstrating their generality for SERS applications. These highly sensitive SERS-active substrates offer novel robust structures for trace detection of chemical and biological analytes.