Comparative Raman spectroscopy studies of photosensitive polymers

Barbet, F.; Bormann, D.; Warenghem, M.; Khelifa, B.; Kurios, Yuri; Reznikov, Yuriy; Simoni, F.

doi:10.1016/s0254-0584(98)00037-6

Cited by 4 publications

(3 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These peaks may originate from the two rotational conformers possible for the α,β-unsaturated ketone in the side group containing the cinnamoyl moiety, as shown in Figure . Since the COand CC bands in the s-cis -ketone are far apart in comparison to those in the s-trans -ketone, , the bands at 1721 and 1630 cm -1 are assigned to the CO stretching vibration and the vinylene CC vibration of the trans-s-cis conformer of the side group, respectively. The bands at 1708 and 1640 cm -1 are assigned to the CO stretching vibration and the vinylene CC stretching vibration of the trans-s-trans conformer of the side group, respectively.…”

Section: Resultsmentioning

confidence: 99%

Photoreaction and Molecular Reorientation in a Nanoscaled Film of Poly(methyl 4-(methacryloyloxy)cinnamate) Studied by Two-Dimensional FTIR and UV Correlation Spectroscopy

et al. 2002

View full text Add to dashboard Cite

Photoreaction and photoinduced molecular reorientations in nanoscaled films of poly(methyl 4-(methacryloyloxy)cinnamate) (PMMCi) were investigated through two-dimensional (2D) correlation analyses of their infrared (IR) and ultraviolet (UV) absorption spectra. In the PMMCi film the presence of three distinct chromophore types was evident: isolated trans-isomeric cinnamoyl moieties and parallel and end-to-end cinnamoyl aggregates. Their photoinduced reorientations take place in the following sequence: isolated trans isomeric chromophores f parallel chromophore aggregates f end-to-end chromophore aggregates. It turns out that they react photochemically at different rates. The PMMCi polymer molecules were found to undergo both photoisomerization and photodimerization upon UV irradiation, with the trans-cis isomerization of the isolated trans isomeric cinnamoyl moieties occurring more rapidly than the photodimerization of the cinnamoyl aggregates. Of the photodimerization processes, the reorientation of the parallel cinnamoyl aggregates precedes that of the end-to-end cinnamoyl aggregates. The isolated chromophores may partly involve in the photodimerization, but its fraction is expected small because of the film in a confined geometry. The cinnamoyl moiety was found to be present as two rotational conformers, trans-s-trans and trans-s-cis conformers. Upon UV irradiation, the trans-s-trans conformer changes before the trans-s-cis conformer. The cinnamoyl moieties undergo a cooperative reorientation with the methacryloyloxy units during photoreaction. The photoinduced molecular reorientations occur in the following sequence: trans isomer f phenyl ring f trans-s-trans conformer f trans-s-cis conformer f photodimer.

show abstract

Section: Resultsmentioning

confidence: 99%

Photoreaction and Molecular Reorientation in a Nanoscaled Film of Poly(methyl 4-(methacryloyloxy)cinnamate) Studied by Two-Dimensional FTIR and UV Correlation Spectroscopy

et al. 2002

View full text Add to dashboard Cite

show abstract

“…When the ODPA-Stilbene PSPI film starts to be irradiated, the intensity of the band at 330 nm (=λ max ) gradually decreases with increasing exposure dose. At the same time, as the irradiation dose increases, a band gradually appears at about 280 nm, corresponding to cis -stilbene units, and an isobestic point is observed at about 290 nm indicating that the cis−trans isomerization of the stilbene units in the polymer film involves a single reaction path 3 UV absorption spectra of the ODPA-Stilbene PSPI films irradiated with unpolarized UV light with varying exposure doses. …”

Section: Resultsmentioning

confidence: 96%

“…Figure shows the UV absorption spectra of the ODPA-Stilbene PSPI films irradiated with UV light at various exposure doses in the range of 0−5 J/cm 2 . Before irradiation with unpolarized UV light, the ODPA-Stilbene PSPI films exhibit absorption maxima at 330 nm (=λ max ); this band is due to absorption by stilbene units in a trans configuration . When the ODPA-Stilbene PSPI film starts to be irradiated, the intensity of the band at 330 nm (=λ max ) gradually decreases with increasing exposure dose.…”

Section: Resultsmentioning

confidence: 99%

UV-Driven Switching of Chain Orientation and Liquid Crystal Alignment in Nanoscale Thin Films of a Novel Polyimide Bearing Stilbene Moieties in the Backbone

Hahm

Lee

et al. 2008

J. Phys. Chem. B

View full text Add to dashboard Cite

A novel photosensitive polyimide, poly(4,4'-stilbenylene 4,4'-oxidiphthalimide) (ODPA-Stilbene PSPI) was newly synthesized. The most surprising feature of this PSPI is that the PSPI films irradiated with linear polarized ultraviolet light (LPUVL) can favorably induce a unidirectional alignment of liquid crystals (LCs) in contact with the film surface and further switch the director of the unidirectionally aligned LCs from a perpendicular direction to a parallel direction with respect to the polarization direction of LPUVL by simply controlling the exposure dose in the irradiation process. These LPUVL-irradiated films were found to provide high anchoring energy to LCs, always giving very stable, homogeneous cells with unidirectionally aligned LCs regardless of the LC alignment directions. In the films, the PSPI polymer chains were found to undergo favorably unidirectional orientation via a specific orientation sequence of the polymer chain segments led by the directionally selective trans-cis photoisomerization of the stilbene chromophore units in the backbone induced by LPUVL exposure. Such unidirectionally oriented polymer chains of the films induce alignment of the LCs along the orientation direction of the polymer chains via favorable anisotropic molecular interactions between the oriented polymer chain segments and the LC molecules. In addition, the PSPI has an excellent film formation processibility; good quality PSPI thin films with a smooth surface are easily produced by simple spin-coating of the soluble poly(amic acid) precursor and subsequent thermal imidization process. In summary, this new PSPI is the promising LC alignment layer candidate with rubbing-free processing for the production of advanced LC display devices, including LC display televisions with large display areas.

show abstract

Spatio-temporal investigation of the crosslinking and the mechanical properties in a UV-curable rubber bearing photo-dimerizable moieties

Colanges,

Ballu,

Lamouroux

et al. 2025

European Polymer Journal

View full text Add to dashboard Cite

Comparative Raman spectroscopy studies of photosensitive polymers

Cited by 4 publications

References 16 publications

Photoreaction and Molecular Reorientation in a Nanoscaled Film of Poly(methyl 4-(methacryloyloxy)cinnamate) Studied by Two-Dimensional FTIR and UV Correlation Spectroscopy

Photoreaction and Molecular Reorientation in a Nanoscaled Film of Poly(methyl 4-(methacryloyloxy)cinnamate) Studied by Two-Dimensional FTIR and UV Correlation Spectroscopy

UV-Driven Switching of Chain Orientation and Liquid Crystal Alignment in Nanoscale Thin Films of a Novel Polyimide Bearing Stilbene Moieties in the Backbone

Spatio-temporal investigation of the crosslinking and the mechanical properties in a UV-curable rubber bearing photo-dimerizable moieties

Contact Info

Product

Resources

About