Polymer Dispersed Liquid Crystals with Nanosized Droplets: SEM, FTIR and UV Spectroscopy Studies
| Autor: | Xavier Coqueret, P. Feneyrou, R. Benmouna, Ulrich Maschke, V. Rachet, P. Le Barny |
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| Rok vydání: | 2006 |
| Předmět: |
chemistry.chemical_classification
Materials science Polymers and Plastics Scanning electron microscope General Chemical Engineering Analytical chemistry Polymer Ultraviolet visible spectroscopy Photopolymer Polymerization chemistry Liquid crystal Polymer chemistry Materials Chemistry Fourier transform infrared spectroscopy Curing (chemistry) |
| Zdroj: | Scopus-Elsevier |
| ISSN: | 2191-0340 0334-6447 |
| DOI: | 10.1515/polyeng.2006.26.7.655 |
| Popis: | Polymer Dispersed Liquid Crystals with nanosized droplets were studied using a chemical formulation consisting of thiol-ene monomers and low molecular weight liquid crystals. The morphology of photocured samples was characterized by Scanning Electron Microscopy and the size distribution of droplets was assessed and correlated to the curing conditions. The photopolymerization was implemented according to the Polymerization Induced Phase Separation method under radiation curing and monitored by FTIR spectroscopy via conversion of the thiol-ene bond S-H at 2570 cm -1 and the allylic C=C bond at 1647 cm -1 . The observed monomer conversion was monitored and analyzed in terms of the applied dose and the amount of diluent added to the thiol-ene formulation. Electro-optical properties were analyzed with UV-spectroscopy. A shift in the reflectivity curve versus wavelength was found under electric activation. The liquid crystal birefringence was obtained from the wavelength at the peaks of oscillations and changes were calculated in terms of the strength of the applied field. Hysteresis and memory effects were evidenced and discussed. |
| Databáze: | OpenAIRE |
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