Polymer-assisted synthesis of metal nanoparticles: development of substrates for surface-enhanced spectroscopies

• Grant number: 12/06211-0
• Support Opportunities: Regular Research Grants
• Duration: June 01, 2012 - May 31, 2013
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Celly Mieko Shinohara Izumi
• Grantee: Celly Mieko Shinohara Izumi
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

Gold and silver nanoparticles (NPs) present an optical resonance in the visible region of the electromagnetic spectrum named surface plasmon resonance. This resonance depends on the size, shape and composition and causes an enhancement of local electric field close to the surface of nanostructures. As a result, NPs have attracted a great deal of interest for application as substrates for surface enhanced spectroscopies such as surface-enhanced Raman spectroscopy (SERS) and surface-enhanced fluorescence (SEF). The control over size and shape and the controlled patterning or self-assembly of nanoparticles into complex structures with organization on multiple length scales is essential for future applications. The employment of nanoparticles associated with polymers is one strategy for attaining different preparative routes for nanostructured materials. In this project, diblock copolymers with two types of blocks will be used: (i) one block with a functional group with high-affinity to Au and Ag and (ii) one spacer hydrophobic block. The size, shape and distance between NPs and fluorophore (a fluorescent conducting polymer) will be determined by the length of polymer blocks. In this project, systematic investigation concerning the SERS and SEF of conducting polymers will be performed. The influence of distance between fluorophore and NPS on the intensity of Raman scattering (SERS) and emission (SEF) will be investigated. Also, the role of absorption/emission band position of conducting polymer and the position of resonance surface plasmon on the SEF process will be studied. The results will be important to set up elements for planning experiments for development of high performance SERS an SEF substrates and for the modification of optical properties of conducting polymers. This project aims to establish a new research line in the Departamento de Química da UFSCar concerning the synthesis and spectroscopic characterization of polymer/plasmonic structure advanced materials. (AU)