ESR studies of magnetically aligned lyotropic liquid crystals

✍ Scribed by Bruce J. Forrest; Leonard W. Reeves

• Publisher: Elsevier Science
• Year: 1983
• Tongue: English
• Weight: 415 KB
• Volume: 32
• Category: Article
• ISSN: 0009-3084
• DOI: 10.1016/0009-3084(83)90071-3

✦ Synopsis

A type I lyotropic liquid crystalline system based on the amphiphile potassium laurate, and possessing positive diamagnetic anisotropy has been investigated using electron spin resonance (ESR) spectroscopy of spin labeled laurate molecules. A comparison has been made of the ESR order parameters and those derived from deuterium nuclear magnetic resonance (NMR). It is proposed that oscillation of the finite miceUes produces additional averaging of the NMR spectra, while this motion is slow on the ESR time scale. Although the perturbation of the bulky spin label precludes a quantitative description of the motion of the hydrocarbon chains, the ESR spectra are entirely consistent with a cylindrical structure for these mesophases, and inconsistent with those of lamellar type structures. It is concluded that these type 1 lyotropic liquid crystals are indeed composed of cylindrical micelles of finite length.