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Long-term aging of Ag/a-C:H:O nanocomposite coatings in air and in aqueous environment

View Article: PubMed Central - PubMed

ABSTRACT

Nanocomposite coatings of silver particles embedded in a plasma polymer matrix possess interesting properties depending on their microstructure. The film microstructure is affected among others also by the RF power supplied during the deposition, as shown by transmission electron microscopy. The optical properties are characterized by UV–vis–NIR spectroscopy. An anomalous optical absorption peak from the Ag nanoparticles is observed and related to the microstructure of the nanocomposite films. Furthermore, a long-term aging of the coatings is studied in-depth in ambient air and in aqueous environments. It is shown that the studied films are not entirely stable. The deposition conditions and the microstructure of the films affect the processes taking place during their aging in both environments.

No MeSH data available.


Changes in the parameters of the surface plasmon resonance of Ag/a-C:H:O nanocomposite films deposited at different RF powers during aging of the films in ambient air and in distilled water: (a) intensity of absorbance at the wavelength of the SPR and at the wavelength of 1000 nm, (b) position of the absorbance maximum, (c) width of the SPR peak (FWHM).
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Figure 9: Changes in the parameters of the surface plasmon resonance of Ag/a-C:H:O nanocomposite films deposited at different RF powers during aging of the films in ambient air and in distilled water: (a) intensity of absorbance at the wavelength of the SPR and at the wavelength of 1000 nm, (b) position of the absorbance maximum, (c) width of the SPR peak (FWHM).

Mentions: The systematic changes in the three SPR peak parameters can be observed in the following pictures. Particularly, the intensities of the absorbance are summarized in figure 9(a), their positions in figure 9(b) and the FWHM in figure 9(c). As for the absorbance intensity, the values were collected from two points of the spectra: at the position of the SPR maximum in the visible part of the spectrum and at the wavelength of 1000 nm. As was already reported above, the intensity of the SPR of the as-prepared films increases with the deposition power and decreases during aging. The overall decrease of the intensity is faster in water than in air and this rate increases with the higher filling factors of the films: for 30 and 40 W films, the absorbance intensity after aging for 1 h in water is at the level of about 5 months of aging in air, for the 45 W film, the aging for 1 h in water corresponds to about 9 months of aging in air, while the intensity after aging for 1 h in water is lower than after aging in air for about 22 months for the films deposited at 50 and 55 W. The absorbance maximum could not be localized in the case of the film deposited at 60 W because the peak is very broad and lies partly in the region where the noise level is higher due to the change of spectrometer detectors. Nevertheless, the overall decrease of the intensity of the absorbance peak is observed in all of the films. However, the situation is different when the changes in the NIR region are taken into account. The absorbance of the as-prepared films increases with the deposition power also in the NIR spectral range. Particularly, the intensity at the wavelength of 1000 nm increases from almost 0 in the case of films with low filling factors up to about 0.9 in the case of the film deposited at 60 W. The aging of the films however shows different effects. The level of absorption almost does not change (or very slightly decreases) in the case of films deposited up to the power of 45 W, while it increases in the case of the films deposited at 50 and 55 W. The intensity of absorption of the film with high filling factor decreases during aging in air or in water, while the decrease is much stronger in the latter case.


Long-term aging of Ag/a-C:H:O nanocomposite coatings in air and in aqueous environment
Changes in the parameters of the surface plasmon resonance of Ag/a-C:H:O nanocomposite films deposited at different RF powers during aging of the films in ambient air and in distilled water: (a) intensity of absorbance at the wavelength of the SPR and at the wavelength of 1000 nm, (b) position of the absorbance maximum, (c) width of the SPR peak (FWHM).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5036476&req=5

Figure 9: Changes in the parameters of the surface plasmon resonance of Ag/a-C:H:O nanocomposite films deposited at different RF powers during aging of the films in ambient air and in distilled water: (a) intensity of absorbance at the wavelength of the SPR and at the wavelength of 1000 nm, (b) position of the absorbance maximum, (c) width of the SPR peak (FWHM).
Mentions: The systematic changes in the three SPR peak parameters can be observed in the following pictures. Particularly, the intensities of the absorbance are summarized in figure 9(a), their positions in figure 9(b) and the FWHM in figure 9(c). As for the absorbance intensity, the values were collected from two points of the spectra: at the position of the SPR maximum in the visible part of the spectrum and at the wavelength of 1000 nm. As was already reported above, the intensity of the SPR of the as-prepared films increases with the deposition power and decreases during aging. The overall decrease of the intensity is faster in water than in air and this rate increases with the higher filling factors of the films: for 30 and 40 W films, the absorbance intensity after aging for 1 h in water is at the level of about 5 months of aging in air, for the 45 W film, the aging for 1 h in water corresponds to about 9 months of aging in air, while the intensity after aging for 1 h in water is lower than after aging in air for about 22 months for the films deposited at 50 and 55 W. The absorbance maximum could not be localized in the case of the film deposited at 60 W because the peak is very broad and lies partly in the region where the noise level is higher due to the change of spectrometer detectors. Nevertheless, the overall decrease of the intensity of the absorbance peak is observed in all of the films. However, the situation is different when the changes in the NIR region are taken into account. The absorbance of the as-prepared films increases with the deposition power also in the NIR spectral range. Particularly, the intensity at the wavelength of 1000 nm increases from almost 0 in the case of films with low filling factors up to about 0.9 in the case of the film deposited at 60 W. The aging of the films however shows different effects. The level of absorption almost does not change (or very slightly decreases) in the case of films deposited up to the power of 45 W, while it increases in the case of the films deposited at 50 and 55 W. The intensity of absorption of the film with high filling factor decreases during aging in air or in water, while the decrease is much stronger in the latter case.

View Article: PubMed Central - PubMed

ABSTRACT

Nanocomposite coatings of silver particles embedded in a plasma polymer matrix possess interesting properties depending on their microstructure. The film microstructure is affected among others also by the RF power supplied during the deposition, as shown by transmission electron microscopy. The optical properties are characterized by UV–vis–NIR spectroscopy. An anomalous optical absorption peak from the Ag nanoparticles is observed and related to the microstructure of the nanocomposite films. Furthermore, a long-term aging of the coatings is studied in-depth in ambient air and in aqueous environments. It is shown that the studied films are not entirely stable. The deposition conditions and the microstructure of the films affect the processes taking place during their aging in both environments.

No MeSH data available.