Search

Abstract: The surface coverage of phosphorylated oligonucleotides immobilized on a zirconium-phosphonate surface was analyzed using X-ray photoelectron spectroscopy (XPS). By quantifying the intensity of the N 1s signal originating from the oligonucleotide and the Zr 3d peak from the metal-phosphonate surface, the surface coverage of the oligonucleotide could be calculated with a modified substrate-overlayer model. We found relatively low surface coverages indicating that once covalently bound via the terminal phosphate the polymer chain further physisorbs to the surface limiting the adsorption of additional molecules. [Copyright &y& Elsevier]

Abstract: Films of the photomagnetic Prussian blue analogue Rb0.7Co4(Fe(CN)6)3.0(Co–Fe PBA) were deposited onto a Melinex® substrate using two different multiple sequential adsorption methods. Film thickness, measured using atomic force microscopy, was controlled by the number of deposition cycles. The photoinduced magnetism known for the bulk Co–Fe PBA at low temperatures is also seen in the thin films, although the response is anisotropic. A photoinduced increase in magnetization is observed when the film is parallel (∥) to the applied magnetic field (H E), while a photoinduced decrease is observed when the film is perpendicular (⊥) to a weak H E. The relationship between the film thickness and the photoinduced decrease in magnetization is explored in this article. The photoinduced decrease is observed for films less than ∼200nm thick. The behavior is explained by invoking a dipolar interaction between primordial ferrimagnetic domains and the photoswitchable pairs arrayed in the quasi-2D thin film. [Copyright &y& Elsevier]