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Reversible photochromism of polynorbornenes bearing spiropyran side groups.

Hauser L, Knall AC, Roth M, Trimmel G, Edler M, Griesser T, Kern W - Monatsh. Chem. (2012)

Bottom Line: In this paper, the synthesis and characterization of poly(norbornene) homo- and copolymers bearing spiropyran side groups are described.Difficulties in the homopolymerization of spiropyrans due to the opened merocyanine form were observed leading to low polymerization yields for homopolymers while copolymers with 10 mol% spiropyran content were prepared in good yield.The switching between the apolar spiropyran form and the zwitterionic merocyanine form also leads to switchable wettability as evidenced by contact angle measurements.

View Article: PubMed Central - PubMed

Affiliation: Institute for Chemistry and Technology of Materials, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria.

ABSTRACT

Abstract: In this paper, the synthesis and characterization of poly(norbornene) homo- and copolymers bearing spiropyran side groups are described. Difficulties in the homopolymerization of spiropyrans due to the opened merocyanine form were observed leading to low polymerization yields for homopolymers while copolymers with 10 mol% spiropyran content were prepared in good yield. Spiropyrans are characterized by their reversible photochromism, which was conserved in the polymers as shown by UV-Vis spectroscopy and FT-IR spectroscopy. The switching between the apolar spiropyran form and the zwitterionic merocyanine form also leads to switchable wettability as evidenced by contact angle measurements.

No MeSH data available.


FT-IR measurement of poly-4 before and after illumination
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Fig3: FT-IR measurement of poly-4 before and after illumination

Mentions: FT-IR measurements (Fig. 3) of irradiated samples before and after relaxation proved the ring-opening nature of the photochemical process. Figure 3 shows the according spectra. Therein, three main differences of the spiropyran and the merocyanine can be observed. After illumination broadening of the peak at 1,276 cm−1 is observed, which can be attributed to the building of the new C=N+ bond in the merocyanine form. The second evidence is a new peak showing up at 1,422 cm−1, which is caused by the formation of the C–O- bond in the merocyanine. Finally, a new peak is observed at 1,595 cm−1, which can be assigned to the C=C double bond in the center of the molecule. After illumination with visible light or thermal treatment, these peaks are again absent in the spectra of the reformed spiropyran polymers.Fig. 3


Reversible photochromism of polynorbornenes bearing spiropyran side groups.

Hauser L, Knall AC, Roth M, Trimmel G, Edler M, Griesser T, Kern W - Monatsh. Chem. (2012)

FT-IR measurement of poly-4 before and after illumination
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4495054&req=5

Fig3: FT-IR measurement of poly-4 before and after illumination
Mentions: FT-IR measurements (Fig. 3) of irradiated samples before and after relaxation proved the ring-opening nature of the photochemical process. Figure 3 shows the according spectra. Therein, three main differences of the spiropyran and the merocyanine can be observed. After illumination broadening of the peak at 1,276 cm−1 is observed, which can be attributed to the building of the new C=N+ bond in the merocyanine form. The second evidence is a new peak showing up at 1,422 cm−1, which is caused by the formation of the C–O- bond in the merocyanine. Finally, a new peak is observed at 1,595 cm−1, which can be assigned to the C=C double bond in the center of the molecule. After illumination with visible light or thermal treatment, these peaks are again absent in the spectra of the reformed spiropyran polymers.Fig. 3

Bottom Line: In this paper, the synthesis and characterization of poly(norbornene) homo- and copolymers bearing spiropyran side groups are described.Difficulties in the homopolymerization of spiropyrans due to the opened merocyanine form were observed leading to low polymerization yields for homopolymers while copolymers with 10 mol% spiropyran content were prepared in good yield.The switching between the apolar spiropyran form and the zwitterionic merocyanine form also leads to switchable wettability as evidenced by contact angle measurements.

View Article: PubMed Central - PubMed

Affiliation: Institute for Chemistry and Technology of Materials, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria.

ABSTRACT

Abstract: In this paper, the synthesis and characterization of poly(norbornene) homo- and copolymers bearing spiropyran side groups are described. Difficulties in the homopolymerization of spiropyrans due to the opened merocyanine form were observed leading to low polymerization yields for homopolymers while copolymers with 10 mol% spiropyran content were prepared in good yield. Spiropyrans are characterized by their reversible photochromism, which was conserved in the polymers as shown by UV-Vis spectroscopy and FT-IR spectroscopy. The switching between the apolar spiropyran form and the zwitterionic merocyanine form also leads to switchable wettability as evidenced by contact angle measurements.

No MeSH data available.