Search

This work aims to provide new insights into the link between the growth mechanisms of functionalized plasma polymer films (PPFs) and the substrate temperature (TS). By means of AFM‐based techniques, it has been demonstrated that the mechanical behavior of the coatings is dramatically affected by TS and the precursor employed (i.e., 1‐propanethiol or 1‐propylamine). While propylamine‐based PPFs behave as hard elastic materials regardless of TS, propanethiol‐based PPFs evolve from viscous liquids to elastic solids with increasing TS. This behavior can be understood considering the glass transition temperature of PPF. For both precursors, the latter is correlated to the cross‐linking density controlled through the energy density brought by positive ions to the growing film. [ABSTRACT FROM AUTHOR]

In the context of protecting Mg‐based nano‐objects for potential hydrogen storage applications, the potential of C:H layer as a barrier polymer material deposited by the plasma‐enhanced chemical vapor deposition process is examined. Corrosion tests reveal (a) good barrier properties of the C:H layer and (b) suggest an increase in the internal stress with the power dissipated in the plasma. The latter is attributed to an increase in the cross‐linking density of the coatings accompanied by an increase in the stiffness as shown by nanoindentation measurements. Finally, for a given set of plasma parameters, Mg‐based nanowires were successfully enrobed by the C:H coatings as evidenced by scanning electron microscopy measurements. [ABSTRACT FROM AUTHOR]

Plasma polymer films are more and more used in numerous applications such as the day-to-day packaging, which requires a good mechanical resistance of the coating. Since mechanical properties are function of the cross-linking degree of the thin films, it is important to understand the relationship between the two. In this work, plasma polymer films were studied in terms of cross-linking degree and mechanical properties, measured by means of ToF-SIMS coupled to PCA and depth-sensing nanoindentation, respectively. The data reveal that when the power increases, the films are more cross-linked and show higher hardness, higher elastic recovery, lower creep strain and an increased ability for self-healing. As the plasma polymer films are more cross-linked, the plasticity drops and the viscoelasticity and hardness increase. [ABSTRACT FROM AUTHOR]

In this work, the plasma polymerization of propanethiol is investigated with the aim to control the thiol density [SH] in the coatings. The results reveal a nearly constant evolution of [SH] regarding the mean power dissipated in the discharge. This peculiar behavior is explained considering (i) mass spectrometry data revealing a similar relative concentration of condensable SH-bearing species in the plasma and (ii) similar energetic conditions at the growing film/plasma interface. Finally, it is observed that the low 〈 P〉 synthesized films are not chemically stable in solution likely due to the release of H2S molecules trapped in the material network. The whole set of our data allows to provide a deeper understanding of the growth mechanism of propanethiol plasma polymer, essential for future development. [ABSTRACT FROM AUTHOR]

In this work, we report on the synthesis of ethyl lactate-based plasma polymer film (ELPPF) by plasma enhanced chemical vapour deposition (PECVD). Using a design of experiments, it appears that, among other, the injected power ( PRF) is the key parameter affecting the ELPPF features. Indeed, we observe a strong decrease of the COO-C/H functionalities (from 12 to 2 at.%) within a limited PRF domain. A more precise analysis of the film chemistry by combining XPS and chemical derivatization reveals that up to 95% of these carboxyl-based functions are esters. On the other hand, we show that the cross-linking degree of the ELPPF can be increased by a factor of two as a function of PRF. This work paves the way for the tailoring of the barrier properties of ELPPF by controlling the ester content and the cross-linking degree of the PPF. [ABSTRACT FROM AUTHOR]

ABSTRACT This work aims to investigate the influence of the substrate temperature on low‐pressure plasma polymerization processes. Emphasis is placed on the mechanical properties and growth mechanism of the plasma polymer films (PPFs). For this purpose, two precursors are considered, differing only by their unsaturation degree: 2‐propen‐1‐ol (CH2═CH–CH2–OH) and propan‐1‐ol (CH3–CH2–CH2–OH). Although propan‐1‐ol‐based PPFs behave like hard elastic solids, 2‐propen‐1‐ol‐based coatings evolve from a liquid film to an elastic solid on increasing the substrate temperature. This behavior is understood considering the evolution of the glass transition temperature of PPFs. The latter is correlated with the cross‐linking degree of the polymeric network governed by the energy density of bombarding ions on the growing film. [ABSTRACT FROM AUTHOR]

Back Cover: This paper aims at identifying the mechanisms controlling the evolution of the thiol content and the chemical stability in aqueous solution of propanethiol plasma polymers. A detailed description combining film analysis and plasma diagnostic assisted by a theoretical approach is provided. Further details can be found in the article by Damien Thiry et. al. on page 606. [ABSTRACT FROM AUTHOR]