XPS depth profiling of an ultrathin bioorganic film with an argon gas cluster ion beam

Abstract

The growing interest in artificial bioorganic interfaces as a platform for applications in emerging areas as personalized medicine, clinical diagnostics, biosensing, biofilms, prevention of biofouling, and other fields of bioengineering is the origin of a need for in detail multitechnique characterizations of such layers and interfaces. The in-depth analysis of biointerfaces is of special interest as the properties of functional bioorganic coatings can be dramatically affected by in-depth variations of composition. In worst cases, the functionality of a device produced using such coatings can be substantially reduced or even fully lost.

Engineering a Poly(3,4-ethylenedioxythiophene):(Polystyrene Sulfonate) Surface Using Self-Assembling Molecules—A Chemical Library Approach

“…To ensure that the silane molecules only adsorbed on the surface, modified PEDOT:PSS films were sputtered using an argon cluster ion beam, and the XPS spectra of the layers sputtered for different times were recorded. In contrast to monoatomic ion beams, the gas cluster ion beam does not destroy chemical bonds in organic materials, allowing the collection of depth profiles of the chemical composition of the studied samples. − In Figure C, the atomic concentrations of fluorine and sulfur were plotted as a function of the sputter time; the eight cycles of sputtering led to the formation of a crater approximately 20 nm deep. The rapid decrease in fluorine signal already observed in the first sputtering cycle indicates that the 3FS molecules adsorbed selectively on the surface and did not penetrate the PEDOT:PSS film.…”

XPS depth profiling of functional materials: applications of ion beam etching techniques

“…For example, the ultrathin oligoglucose bioorganic films deposited on the oxidized silicon wafers were sputtered by Ar n + GCIB at 10 keV and 10 nA and analyzed using an XPS technique. 86 It was found that there was no substantial damage during Ar 2500 + gas cluster sputtering to the ultrathin carbohydrate layers, which was underpinned by a stable chemical composition versus sputter-time. Self-assembled monolayers (SAMs) have been widely studied as promising hybrid systems for practical applications in electronics and so on.…”