金纳米粒子在氨基表面上的组装-pH值的影响

用原子力显微镜（AFM）和表面增强喇曼光谱（SERS）研究了pH值对金纳米粒子在Au／巯基苯胺自组装膜表面上组装效果的影响．AFM结果表明，金纳米粒子在表面上的覆盖度随pH值表现出规律性的变化，巯基苯胺自组装膜的SERS强度随pH值的变化也有类似的趋势．在磁性环境下，氨基未质子化，金粒子难以组装上，而在酸性条件下，氨基质子化带正电，金粒子与基底容易结合．我们认为金纳米粒子和氨基之间的作用属于静电力，pH值同时影响膜表面氨基的质子化程度和金纳米粒子表面的带电量．

pH-Dependent Assembling of Gold Nanoparticles on p-Aminothiophenol Modified Gold Substrate

An nanoparticles are assembled on gold substrate modified with p-aminothiophenol.AFM measurements show that the coverage of Au nanoparticles is closely related to the pH value of colloids. The SERS intensity also changes with the pH value, which is well consistent with the pH-dependent change of the coverage. In alkaline solution, the amino group is not protonated, and An particles can not be adsorbed on the substrate: while under acidic environment, protonation makes the amino group positively charged and the adsorption gets easier. The interaction between the particles and the substrate is considered to be electrostatic. The PH value, which controls the coverage of Au nanoparticles. affects both the protonation of the amino group and the quantity of the negative charge of Au particles.