A terpyridine-functionalized perylene bisimide chromophore (TPBI) has been used as a building block in the stepwise, layer-by-layer fabrication of self-assembled Fe-TPBI multilayers on gold, with the assembled supramolecular chains oriented approximately perpendicular to the gold surface. Time-resolved spectroscopy measurements seem to indicate that the energy absorbed by the multilayer is promptly dissipated to the gold surface by ultrafast processes.

We demonstrate the potential of an innovative technique, pulsed radiofrequency glow discharge time-of-flight mass spectrometry, for the molecular depth profiling of polymer materials. The technique benefits from the presence, in the afterglow of the pulsed glow discharge, of fragment ions that can be related to the structures of the polymers under study. Thin films of different polymers (PMMA, PET, PAMS, PS) were successfully profiled with retention of molecular information along the profile. Multilayered structures of the above polymers were also profiled, and it was possible to discriminate among layers having similar elemental composition but different polymer structure. Copyright # 2009 John Wiley & Sons, Ltd.Analysis of polymer-based films is extremely central in the field of materials science since polymers are currently used for a multiplicity of manufactured goods and technological applications. Characterization of paints and pigment films, study of coating performance, development of polymerbased electronic devices such as poly-LED displays or organic photovoltaic systems, detailed analysis of food packaging, and investigation of ion-exchange membranes, are some important fields of interest that require detailed depth-resolved investigation of polymer-based materials. Such investigations often require not only knowledge of the elemental depth profile, but also detailed molecular information along the depth, i.e. 'molecular depth profiling'. In general, several techniques can be used to obtain in depth information -mostly elemental -from polymer systems, [1][2][3][4][5] but no existing technique meets the technological requirements for high-resolution molecular depth profiling in the sense defined above. Among mass spectrometry techniques, in the last few years the development of polyatomic primary ion sources and, more recently, the use of low-energy monoatomic beams have opened new perspectives in the secondary ion mass spectrometry (SIMS) of organic materials and polymers. In general, SIMS depth profiling is not universally applicable for molecular depth profiling of organic compounds because of the ion beam induced degradation phenomena active under high energetic (keV) bombardment intrinsic to the technique. The effect of such high energetic bombardment, in the so-called dynamic-SIMS mode, is a severe damage of the molecular structure of the organic compounds and the resulting detection of elemental information only. In the case of polyatomic ion beams, such as C 60 beams, the capability to perform molecular depth profiling could be connected with the high sputter yield and the very low penetration depth of the polyatomic ions that 'sputter away' the damaged region leaving a more or less undamaged surface behind. 6 Recently, some of us highlighted the fact that the feasibility of molecular depth profiling by means of polyatomic beams is strongly dependent on the radiation chemistry of the particular polymer under analysis, 6 probably because fast erosion results from ion beam induced reactions occur...

Glow discharge mass spectrometry has been widely used for trace and ultra-trace element analysis of high-purity alloys. A novel pulsed radio frequency glow discharge time-of-flight mass spectrometer (rf GD TOFMS) has been developed that retains the pulsed radio frequency analytical ion source to provide ion signal enhancement due to processes involving Penning ionisation. A time-resolved detection mode has been implemented to sample the afterglow regime of the pulse profile, corresponding to the highest ion signal intensities. Here, the performance of rf GD TOFMS in isotope differentiation is discussed. Anodic tantala films, comprising 18 O-rich layers of controlled thicknesses and locations, were formed by appropriate combination of anodising of tantalum in electrolytes enriched with 18 O isotopes and of natural O isotopic abundance. Transmission electron microscopy (TEM) and radio frequency glow discharge optical emission spectrometry (rf GD OES) analyses were performed to examine the morphology and elemental distributions of the specimens, while the content of 18

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The depth resolutions achieved by time-of-flight secondary ion mass spectrometry (TOF-SIMS) and glow discharge optical emission spectroscopy (GD-OES) are comparable for the analysis of relatively flat specimens. However, the precision of sputtering-induced depth profiling techniques has been shown to be dramatically influenced by the initial roughness of specimen surface. The effect of the specimen roughness on the depth resolution achieved by both techniques has been examined here using textured aluminium substrates supporting anodic oxide films. As a result of dissimilarities in the sputtering processes, TOF-SIMS and GD-OES show significantly different elemental depth profiles for electrolyte-derived species incorporated into anodic oxide films formed on superpure aluminium substrates of controlled texture.

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