Interaction forces between poly(amidoamine) (PAMAM) dendrimers adsorbed on gold surfaces

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• 作者：Daisuke Hiraiwa ; Tomokazu Yoshimura and Kunio Esumi
• 关键词：Colloidal probe atomic force microscope ; Poly(amidoamine) dendrimer ; Gold surface ; Quartz crystal microbalance
• 刊名：Journal of Colloid and Interface Science
• 出版年：2006
• 出版时间：15 June 2006
• 年：2006
• 卷：298
• 期：2
• 页码：982-986
• 全文大小：184 K

文摘

Interaction forces between two gold surfaces with adsorbed poly(amidoamine) (PAMAM) dendrimers (generations G3.0 and G5.0) have been investigated using colloidal probe atomic force microscopy (AFM). In the absence of dendrimers or at their low concentrations, an attractive force derived from the van der Waals interaction was observed. On the other hand, this attractive interaction changed to repulsion with increasing dendrimer concentration. The origin of the repulsion can be attributed to either an electric double layer interaction or a steric effect of the adsorbed dendrimers, depending on the concentration of dendrimer. The steric hindrance was also influenced by the generation of the dendrimer; the force-detectable distance in the presence of PAMAM G5.0 dendrimer was slightly longer than that in the presence of G3.0 dendrimer. In order to estimate the occupied area of each dendrimer adsorbed on gold, quartz crystal microbalance (QCM) measurement was also carried out.