Preparation And Performance Characterization Of Gold Nanorods-silver Core-shell Nanoparticles (AuNR@Ag)

Anisotropic metal nanoparticles,especially gold nanorods?AuNRs?have attracted much attention because of their special optical properties.In this dissertation,AuNRs were prepared by seed growth method,and AuNR@Ag core-shell nanostructures were prepared using AuNRs as cores.The application of core-shell structures modified by thermosensitive polymer in catalysis and Raman enhancement was studied.The main research works and conclusions are as following:?1?The effects of ascorbic acid?AA?concentration,silver nitrate concentration and reaction time on the synthesis of AuNRs by seed growth method were studied.The uniform AuNRs with an aspect ratio?AR?of 4.8 were successfully prepared under optimized reaction conditions.?2?Core-shell gold nanorods-silver?AuNR@Ag?nanostructures were prepared from purified AuNRs as cores via the reduction of silver nitrate by ascorbic acid?AA?.The effects of AuNRs dosage,AA dosage and pH value on the synthesis of the AuNR@Ag were studied.The AuNR@Ag nanostructures were successfully prepared by optimizing reaction conditions,of which the thin side of silver shell was approximately 1-2 nm and the thick side was 7 nm.?3?Surface modification of AuNR@Ag nanostructures by thermosensitive polymer poly?N-isopropyl acrylamide?greatly improved the stability of nanostructures,as catalyst they showed"smart"self-inhibitory catalytic activity due to the thermosensitive effect of polymer periphery.This self-inhibitory catalytic activity should be significant to avoid overheating in exothermal reactions.?4?The AuNR@Ag nanostructures were also used as an active substrate to explore surface enhanced raman scattering?SERS?of the probe molecule p-amidothiol phenol?pATP?.It was found that the signal intensity of AuNR@Ag nanostructures and AuNR@Ag nanostructures modified by PNIPAM were approximately 13.6 times and8.5 times of the samples in water at 1563 cm^-1.This showed that the AuNR@Ag and polyer mododied AuNR@Ag nanostructures had good SERS properties.?5?The AuNR@Ag nanostructures modified by PNIPAM could be doped into organosilicon elastomer to prepare nano-metal composited silicone materials which showed obvious absorbance between 400-800 nm with red color.