Gold Nanorod鈥損NIPAM Hybrids with Reversible Plasmon Coupling: Synthesis, Modeling, and SERS Properties
文摘
The thermoresponsive optical properties of Au nanorod-doped poly(N-isopropylacrylamide) (Au NR鈥損NIPAM) microgels with different Au NR payloads and aspect ratios are presented. Since the volume phase transition of pure pNIPAM microgels is reversible, the optical response reversibility of Au NR鈥損NIPAM hybrids is systematically analyzed. Besides, extinction cross-section and near-field enhancement simulations for Au NR鈥搈icrogel hybrids are performed using a new numerical method based on the surface integral equation method of moments formulation (M3 solver). Additionally, the Au NR鈥搈icrogel hybrid systems are expected to serve as excellent broadband surface-enhanced Raman scattering (SERS) substrates due to the temperature-controlled formation of hot spots and the tunable optical properties. The optical enhancing properties related to SERS are tested with three laser lines, evidencing excitation wavelength-dependent efficiency that can be easily controlled by either the aspect ratio (length/width) of the assembled Au NR or by the Au NR payload per microgel. Finally, the SERS efficiency of the prepared Au NR鈥損NIPAM hybrids is found to be stable for months.