| Summary: | 博士 === 國立臺灣大學 === 高分子科學與工程學研究所 === 107 === In this study, dendritic polymers with silver nanoparticle were developed as polymer nanoparticle arrays for surface enhanced Raman scattering (SERS) detection. By using a chemical grafting method, we have successfully prepared a floating-typed surface-enhanced Raman scattering (SERS) substrate with the uniform nanoparticle arrays of silver nanoparticles (AgNPs) immobilized on the dendron-exfoliated graphene oxide (GO) and reduced graphene oxide (rGO) nanosheets. These poly(urea/malonamide) dendrons were synthesized, and then grafted on the dendron-exfoliated rGO nanosheets based on a building block of dual functional 4-isocyanato-4’-(3,3-dimethyl-2,4-dioxo-azetidino)-diphenylmethane (IDD). By using dendron-rGO nanosheets as templates for hosting AgNPs, the particle size (D) and interparticle gap (W) of AgNPs could be manipulated by the incorporation of dendrons of various generations (0.5, 1.5, and 2.5 generations), evaluated by transmission electron microscopy. The results indicate that the nanohybrids with 1.5 generation-dendron exhibited stable, enormous, and linear-quantitative Raman enhancement in malachite green detection (1-100 ppm), due to the presence of the lowest W/D ratio (0.8±0.6) and interparticle gap (7.6±5.3 nm). The limit of detection (LOD) of malachite green is lower than 2.7×10-11 M (0.01 ppb). AgNPs@rGO-dendritic derivative nanohybrids as floating and flexible SERS substrates provide ultrasensitive and stable SERS detection in the solutions, exhibiting great potential for practical applications in detecting environmental pollutants. Furthermore, a series of cationic dentritic type poly (urea/malonamide) surfactants were successfully developed. These cationic surfactants were chosen to electrostatically adsorb on the negatively charged GO to form nanocomposites, whereas the AgNPs were reduced on the nanocomposites. Subsequently, the honeycomb-like films with AgNPs were prepared by the breath figure method. As compared with the flat samples of AgNPs@GO-cationic surfactant nanocomposites, the honeycomb-like films with AgNPs could effectively enhance Raman signal in R6G detection. This could be attributed to the additional effects of honeycomb-like structure and well-distributed AgNPs. It is concluded that the honeycomb-like SERS substrates were successfully achieved with great potential of enhancing SERS effect significantly.
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