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Enhancement of polymer endurance to UV light by incorporation of semiconductor nanoparticles.

Rudko G, Kovalchuk A, Fediv V, Chen WM, Buyanova IA - Nanoscale Res Lett (2015)

Bottom Line: UV protection is achieved by diminishing the probability of photo-activated formation of defects in polymer.The sources of polymer protection are the lowering of the efficiency of polymer excitation via partial absorption of incident light by the embedded nanoparticles as well as the de-excitation of the macromolecules that have already absorbed UV quanta via energy drain to nanoparticles.Within the nanoparticles, the energy is either dissipated by conversion to the thermal energy or reemitted as visible-range photoluminescence quanta.

View Article: PubMed Central - PubMed

Affiliation: V. Lashkaryov Institute of Semiconductor Physics of National Academy of Sciences of Ukraine, 45, Pr. Nauky, Kiev, 03028 Ukraine.

ABSTRACT
Improvement of polyvinyl alcohol stability against ultraviolet (UV) illumination is achieved by introducing cadmium sulfide (CdS) nanoparticles into the polymeric matrix. Enhancement of stability is analyzed by optical characterization methods. UV protection is achieved by diminishing the probability of photo-activated formation of defects in polymer. The sources of polymer protection are the lowering of the efficiency of polymer excitation via partial absorption of incident light by the embedded nanoparticles as well as the de-excitation of the macromolecules that have already absorbed UV quanta via energy drain to nanoparticles. Within the nanoparticles, the energy is either dissipated by conversion to the thermal energy or reemitted as visible-range photoluminescence quanta.

No MeSH data available.


The scheme of the UV-induced processes in the unloaded polymer (a, c) and CdS/PVA nanocomposite (b, d). (a) Untreated unloaded PVA. The zigzag lines serve to show the macromolecules in the polymer. (b) Untreated nanocomposite CdS/PVA. The circles denote CdS NPs in the polymeric matrix. (c) Formation of the UV-induced defects in the polymer. (d) Processes in CdS/PVA under UV illumination: I, direct absorption of UV light by NPs and further emission of PL quanta (the process is labeled PL) or thermal dissipation of energy via nonradiative process (the process is labeled NR); II, excitation transfer from photo-excited polymer macromolecules to NPs with further emission of PL quanta (the process is labeled PL) or thermal dissipation of energy (the process is labeled NR); III, the same process as in unloaded PVA: formation of the UV-induced defects in the matrix of nanocomposite.
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Fig4: The scheme of the UV-induced processes in the unloaded polymer (a, c) and CdS/PVA nanocomposite (b, d). (a) Untreated unloaded PVA. The zigzag lines serve to show the macromolecules in the polymer. (b) Untreated nanocomposite CdS/PVA. The circles denote CdS NPs in the polymeric matrix. (c) Formation of the UV-induced defects in the polymer. (d) Processes in CdS/PVA under UV illumination: I, direct absorption of UV light by NPs and further emission of PL quanta (the process is labeled PL) or thermal dissipation of energy via nonradiative process (the process is labeled NR); II, excitation transfer from photo-excited polymer macromolecules to NPs with further emission of PL quanta (the process is labeled PL) or thermal dissipation of energy (the process is labeled NR); III, the same process as in unloaded PVA: formation of the UV-induced defects in the matrix of nanocomposite.

Mentions: The experimental facts illustrated by Figures 1, 2, and 3 show that by incorporating NPs into the polymeric matrix, one can minimize the harmful influence of UV exposure on the polymeric component of the composite. In what follows, we will discuss possible mechanisms of NP participation in polymer protection and illustrate them by the schemes in Figure 4.Figure 4


Enhancement of polymer endurance to UV light by incorporation of semiconductor nanoparticles.

Rudko G, Kovalchuk A, Fediv V, Chen WM, Buyanova IA - Nanoscale Res Lett (2015)

The scheme of the UV-induced processes in the unloaded polymer (a, c) and CdS/PVA nanocomposite (b, d). (a) Untreated unloaded PVA. The zigzag lines serve to show the macromolecules in the polymer. (b) Untreated nanocomposite CdS/PVA. The circles denote CdS NPs in the polymeric matrix. (c) Formation of the UV-induced defects in the polymer. (d) Processes in CdS/PVA under UV illumination: I, direct absorption of UV light by NPs and further emission of PL quanta (the process is labeled PL) or thermal dissipation of energy via nonradiative process (the process is labeled NR); II, excitation transfer from photo-excited polymer macromolecules to NPs with further emission of PL quanta (the process is labeled PL) or thermal dissipation of energy (the process is labeled NR); III, the same process as in unloaded PVA: formation of the UV-induced defects in the matrix of nanocomposite.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385109&req=5

Fig4: The scheme of the UV-induced processes in the unloaded polymer (a, c) and CdS/PVA nanocomposite (b, d). (a) Untreated unloaded PVA. The zigzag lines serve to show the macromolecules in the polymer. (b) Untreated nanocomposite CdS/PVA. The circles denote CdS NPs in the polymeric matrix. (c) Formation of the UV-induced defects in the polymer. (d) Processes in CdS/PVA under UV illumination: I, direct absorption of UV light by NPs and further emission of PL quanta (the process is labeled PL) or thermal dissipation of energy via nonradiative process (the process is labeled NR); II, excitation transfer from photo-excited polymer macromolecules to NPs with further emission of PL quanta (the process is labeled PL) or thermal dissipation of energy (the process is labeled NR); III, the same process as in unloaded PVA: formation of the UV-induced defects in the matrix of nanocomposite.
Mentions: The experimental facts illustrated by Figures 1, 2, and 3 show that by incorporating NPs into the polymeric matrix, one can minimize the harmful influence of UV exposure on the polymeric component of the composite. In what follows, we will discuss possible mechanisms of NP participation in polymer protection and illustrate them by the schemes in Figure 4.Figure 4

Bottom Line: UV protection is achieved by diminishing the probability of photo-activated formation of defects in polymer.The sources of polymer protection are the lowering of the efficiency of polymer excitation via partial absorption of incident light by the embedded nanoparticles as well as the de-excitation of the macromolecules that have already absorbed UV quanta via energy drain to nanoparticles.Within the nanoparticles, the energy is either dissipated by conversion to the thermal energy or reemitted as visible-range photoluminescence quanta.

View Article: PubMed Central - PubMed

Affiliation: V. Lashkaryov Institute of Semiconductor Physics of National Academy of Sciences of Ukraine, 45, Pr. Nauky, Kiev, 03028 Ukraine.

ABSTRACT
Improvement of polyvinyl alcohol stability against ultraviolet (UV) illumination is achieved by introducing cadmium sulfide (CdS) nanoparticles into the polymeric matrix. Enhancement of stability is analyzed by optical characterization methods. UV protection is achieved by diminishing the probability of photo-activated formation of defects in polymer. The sources of polymer protection are the lowering of the efficiency of polymer excitation via partial absorption of incident light by the embedded nanoparticles as well as the de-excitation of the macromolecules that have already absorbed UV quanta via energy drain to nanoparticles. Within the nanoparticles, the energy is either dissipated by conversion to the thermal energy or reemitted as visible-range photoluminescence quanta.

No MeSH data available.