Synthesis and mesomorphic behavior of a new series of side-chain liquid crystalline polymethacrylates bearing 2,6-naphthylene-based mesogen

✍ Scribed by Eleftherios V. Tourasanidis; George P. Karayannidis

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 315 KB
• Volume: 37
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(19990715)37:14<2391::aid-pola13>3.0.co;2-6

✦ Synopsis

A new homologous series of liquid crystalline (LC) polymethacrylates, the poly[-(2-phenoxycarbonyl-naphthalene-6-yloxy)alkyl methacrylate]s, in which the length of the alkyl spacer is varied between 3 and 12 methylene units, have been synthesized by free-radical polymerization. The prepared polymers were studied by IR and 1 H-NMR spectroscopy, viscosity measurements, differential scanning calorimetry (DSC), and polarized microscopy. Polymers with 3 or 4 methylene units spacer were glassy in nature, whereas those with 5-12 methylene units spacer exhibited smectic behavior. The glass transition temperatures decrease on increasing spacer length. The isotropization temperatures and the corresponding transition entropies showed an odd-even effect, with the odd members exhibiting the higher values. This effect attenuates on increasing spacer length.