Alkanephosphonates on hafnium-modified gold: a new class of self-assembled organic monolayers.

A new method for assembling organic monolayers on gold is reported that employs hafnium ions as linkers between a phosphonate headgroup and the gold surface. Monolayers of octadecylphosphonic acid (ODPA) formed on gold substrates that had been pretreated with hafnium oxychloride are representative of this new class of organic thin films. The monolayers are dense enough to completely block assembly of alkanethiols and resist displacement by alkanethiols.

Substrates for direct imaging of chemically functionalized SiO2 surfaces by transmission electron microscopy.

A significant challenge in materials characterization is the determination of the structure of nanoparticle assemblies that have been deposited on solid substrates, such as SiO2. The best method for obtaining quantitative information about structure, size, and spacing on the nanometer-length scale is TEM; however, commercially available TEM grids offer a limited range of substrate materials. In addition, the compositions of these grids do not permit much chemical processing.