金纳米粒子自球形向棒状的转变和生长的光化学法研究

在含有HAuCl₄和十六烷基三甲基氯化铵(CTMAC)的DMF-H₂O-丙酮介质中, 以CTMAC形成的胶束为模板, 丙酮为光敏剂, 光化学还原法制备了不同长径比的棒状金纳米粒子. 通过改变DMF∶H₂O (V/V)的比例来改变溶液的极性, 增加胶束聚集数, 实现了自球形胶束向棒状的转变, 从而得到以金纳米棒占优势的金胶体溶液. 研究了HAuCl₄和CTMAC的浓度以及照射时间对金纳米棒生长的影响, 在最佳实验条件下, 获得了直径在20～22 nm, 长为0.5～3 μm的金纳米棒, 讨论了光化学反应和金纳米粒子在形成的棒状胶束中的自组装生长机理.

Study on the Transformation from Spherical to Rodlike Gold Nanoparticle and Its Self-organization Growth by Photochemical Method

Gold nanorods with different aspect ratios were synthesized by the photochemical reduction method in H₂O-DMF-acetone medium containing HAuCl₄ and cetyltrimethyl ammonium chloride (CTMAC), by means of forming CTMAC micelle as template and acetone as photosensitizer. The transformation from spherical to rodlike micelle was realized by changing the ratio of DMF∶H₂O (V/V) to turn the polarity of the medium and increasing micelle aggregation number, as a result, a colloidal solution predominated by rodlike gold nanoparticles was obtained. The influence of the concentration of HAuCl₄ and CTMAC as well as irradiation time on the growth of nanoparticle self-organization was investigated. Under optimal conditions, gold nanorods with a diameter of 20 to 22 nm and a length of 0.5 to 3 μm were synthesized. The mechanisms of the photochemical reaction and gold nanoparticle self-organization in rodshaped micelle were discussed in detail.