The synthesis, mesomorphic and dielectric investigation of new unsymmetrical bent-core mesogens derived from 3-hydroxybenzoic acid


Ocak H. , Ahlatcıoğlu Özerol E. , Çelikel F. Ç. , Okutan M. , Bilgin Eran B.

CHEMICAL PAPERS, cilt.74, ss.3899-3911, 2020 (SCI İndekslerine Giren Dergi) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 74
  • Basım Tarihi: 2020
  • Doi Numarası: 10.1007/s11696-020-01203-4
  • Dergi Adı: CHEMICAL PAPERS
  • Sayfa Sayıları: ss.3899-3911

Özet

The synthesis, mesomorphic and dielectric investigation of new unsymmetrical bent-core mesogens derived from 3-hydroxybenzoic acid central core with linked two rodlike units carrying (S)-3,7-dimethyloctyloxy group and an n-alkyloxy chain at both terminals are presented. The liquid crystalline properties of the new unsymmetrical bent-core materials have been investigated by polarizing optical microscopy and differential scanning calorimetry. New compounds with the reversed ester linking unit exhibit a monotropic or enantiotropic columnar mesophase at lower temperatures as compared to analogs with a straight chain depending on the presence of the branched (S)-3,7-dimethyloctyloxy terminal chain. Dielectric measurements for one of the bent-core mesogens, 3-[[4-[[4-(octyloxy)benzoyl]oxy]benzoyl]oxy]benzoic acid 4-[[4-((S)-3,7-dimethyloctyloxy)phenoxy]carbonyl]phenyl ester (OBDPE), have been carried out on the angular frequency range from 25.12 to 50265k rad/s at different temperatures. Thanks to dielectric measurements, real and imaginary dielectric constant, conductivity mechanism and dielectric relaxation mechanism of OBDPE were obtained.