Fe(CO) 5 is one of the most common precursors used in focused electron beam induced deposition (FEBID). Since high-energy electrons interacting with matter produce large amounts of secondary electrons with energies <50 eV, those generated within the substrate in FEBID are expected to play a major role in the dissociation process of the precursor molecules. The aim of this study is to identify the role of the secondary electrons in the deposition process of Fe(CO) 5 and the relevant dissociation mechanisms, using an electron stimulated desorption system with 4−33 eV electrons. The desorption of charged fragments from thin films of Fe(CO) 5 , condensed on Xe or onto a Pt foil, was measured as a function of incident electron energy, incident current, and thickness of both Fe(CO) 5 and Xe films. Both dissociative electron attachment (DEA) and dipolar dissociation (DD) are involved in the production of anions, specifically, C − and O − , and Fe(CO) x − (x = 0−4). Cations C + , O + , CO + , and Fe(CO) x + (x = 0−4) were detected with desorption thresholds in the ∼15−25 eV range. These fragments are produced via direct dissociative processes. This study reveals the detailed dissociation mechanisms of Fe(CO) 5 induced by low-energy electron impact by the direct observation of Fe(CO) x fragments under different conditions, thus confirming the frequently proposed mechanisms of deposition of Fe by FEBID.

Industrial low-density polyethylene (LDPE) was aged in stagnant distilled water during one year. Two types of this material were studied. The first one was without additives and the second type was doped with 4% of hindered-amine light stabilizers (HALS). Using X-ray photoelectron spectroscopy (XPS), the evidence that an oxidation occurs was demonstrated for the two types of LDPE (with and without HALS). One objective was to observe the chemical groups resulting of the ageing and to propose a mechanism of hydrolytic degradation for LDPE. The analysis of C1s spectra shows that the main oxidation products are C–O and C=O groups. Unlike the hydrolytic degradation of polypropylene, there is no presence of O=C–O groups, which suggests that there is no oxidative chain scission during hydrolytic ageing of the LDPE. The other objective of the study was to observe if the HALS can have an influence in the hydrolytic ageing of the LDPE. The values of the atomic concentration of the oxygen for the two types of samples show that the HALS could slightly slow down the oxidation of the LDPE

Desorption of anions stimulated by 1-18 eV electron impact on self-assembled monolayer (SAM) films of single DNA strands is measured as a function of film temperature (50-250 K). The SAMs, composed of 10 nucleotides, are dosed with O 2 . The OH − desorption yields increase markedly with exposure to O 2 at 50 K and are further enhanced upon heating. In contrast, the desorption yields of O − , attributable to dissociative electron attachment to trapped O 2 molecules decrease with heating. Irradiation of the DNA films prior to the deposition of O 2 shows that this surprising increase in OH − desorption, at elevated temperatures, arises from the reaction of O 2 with damaged DNA sites. These results thus appear to be a manifestation of the so-called "oxygen fixation" effect, well known in radiobiology.

The aim of this work is to coat silk fibers (SF) with polymer of acrylic acid (PAA) using an atmospheric pressure glow discharge (APGD) plasma jet in order to immobilize antimicrobial peptide LL‐37. The polymer properties are characterized by contact angle goniometry (CAG), XPS, AFM and SEM. The CA of the SF film can be decreased to 34°, and the surface roughness of PAA in the center of plasma jet is larger than in other areas. Compared with the original SF, the concentration of carboxyl group increases greatly when the SF are modified by Ar plasma jet polymerization of AA. The augmentation of functional groups is very useful to immobilize larger concentrations of microbial peptide LL‐37 on the SF surface, and the satisfactory antimicrobial activity on inhibiting the Escherichia coli (E. coli) is thereby achieved.magnified image