Accession Number : ADA333726
Title : Structural Distortion of Dendrimers on Gold Surfaces: A Tapping-Mode AFM Investigation
Descriptive Note : Technical rept. 1 Aug 97-28 Feb 98
Corporate Author : TEXAS A AND M UNIV COLLEGE STATION DEPT OF CHEMISTRY
Personal Author(s) : Hierlemann, Andreas ; Campbell, Joseph K. ; Baker, Lane A. ; Crooks, Richard M. ; Ricco, Antonio J.
PDF Url : ADA333726
Report Date : 05 JAN 1998
Pagination or Media Count : 15
Abstract : Atomic force microscopy (AFM) investigations of polyamidoamine (PAMAM) Starburst (Trademark) dendrimers, generations 4 and 8 (G4, G8), absorbed on Au (111) surfaces were conducted. By controlling dendrimer concentration and exposure time during adsorption, coverages ranging from completely isolated molecules to a monolayer were prepared. The individual dendrimer molecules forming a monolayer were clearly imaged. Upon exposure to hexadecanethiol, the shapes of individual dendrimers change and they become taller and narrower as more stable thiol-Au bonds replace some of the amine-Au bonds. In the case of monolayers, exposure to hexadecanethiol causes the dendrimers to gradually agglomerate, forming dendrimer "pillars" up to 30 nm in height and freeing progressively more surface area for thiol adsorption.
Descriptors : *ADSORPTION, *GOLD, STRUCTURAL PROPERTIES, SUBSTRATES, CHEMICAL BONDS, AMINES, THIOLS.
Subject Categories : Polymer Chemistry
Distribution Statement : APPROVED FOR PUBLIC RELEASE