Acta Phys. -Chim. Sin. ›› 1998, Vol. 14 ›› Issue (11): 968-974.doi: 10.3866/PKU.WHXB19981103

• ARTICLE • Previous Articles     Next Articles

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

Fu Xiao-Yi, Mou Tao, Wang Jian, Zhu Tao, Liu Zhong-Fan   

  1. Center for Intelligent Materials Research(CIMR),College of Chemistry Molecular Engineering,Peking University,Beijing 100871
  • Received:1998-01-20 Revised:1998-03-23 Published:1998-11-15
  • Contact: Liu Zhong-Fan

Abstract:

Au 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 Au 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.

Key words: Au nanoparticles, Self-assembly, AFM, SERS