Characterization of a nematic mixture by reversed‐phase HPLC and UV spectroscopy: an application to phase behaviour studies in liquid crystal–CO 2 systems
2007; Taylor & Francis; Volume: 34; Issue: 5 Linguagem: Inglês
10.1080/02678290601010915
ISSN1366-5855
AutoresAna R. Brás, Sara Carolina Henriques, Teresa Casimiro, Ana Aguiar‐Ricardo, João Sotomayor, Jorge Caldeira, Celina Santos, Madalena Dionı́sio,
Tópico(s)Photochemistry and Electron Transfer Studies
ResumoIn the present work a simple but selective reversed‐phase high performance liquid chromatographic method (HPLC) was developed for the analysis of the nematic liquid crystal mixture E7 to determine precisely the composition of the liquid crystal mixture used in PDLC film preparation. Ultraviolet absorption spectrophotometry experiments were carried out to determine the HPLC detection wavelength and to characterize the absorptivity constants of E7 constituents. The technique developed is applied in the case of equilibrium solubility studies for E7 in supercritical carbon dioxide (scCO2). The results indicate unambiguously that scCO2 can fractionate the mixture towards the E7 components. The four single component peaks of the E7 mixture were distinctively separated by this method, which enabled the determination of the solubility of E7 constituents in the scCO2.
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