Facile synthesis of carboxymethyl curdlan-capped silver nanoparticles and their application in SERS.

Carboxymethyl curdlan (CMc), a β-D-glucan derivative, was used in the photoinduced synthesis of Ag nanoparticles. The size, size distribution, morphology and structure of the as-prepared Ag nanoparticles were investigated with UV-vis spectroscopy, transmission electron microscopy (TEM), energy-dispersive X-ray spectrometry (EDX), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The experimental results indicated that the particle size increased and the size distribution became broader with increasing the concentrations of both AgNO3 and CMc, and the effect of the latter was more pronounced. With the CMc concentration increasing, the diversity of morphology was obtained as a result of the plasmon excitation and the role of CMc. It was found that CMc played an important role in the synthesis and stabilization of Ag nanoparticles through a series of contrastive experiments. The enhancement effect of the produced Ag nanoparticles in surface enhanced Raman scattering (SERS) was also investigated.