비키랄성 바나나 형태의 분자를 갖는 액정의 합성과 특성에 관한 연구
Study on synthesis and characterization of liquid crystals from achiral banana-shaped molecule
비키랄성 바나나형태분자 액정 화학;
- 원문 URL
New banana-shaped compounds, derivatives of 4-chloro-1,3- phenylene bis[4-(4-alkyloxyphenyliminomethyl)benzoate] and 4-bromo- 1,3-phenylene bis[4-(4-alkyloxyphenyliminomethyl)benzoate] were synth- esized with variation of the substituent(X=H, F or Cl); their mesomorpic properties are described. The smectic phases were characterized by differential scanning calorimetry(DSC), polarizing optical microscopy(POM), triangular wave method, and X-ray diffractometry(XRD) in the small and wide angle regions. The introduction of a lateral halogen-substituent in the Schiff's base moiety prevents the regular stacking of molecules and results in lowering the transition temperature of the switchable banana phase. The presence of vinyl group at the terminals of banana-shaped molecules induced a lowering the melting temperature. The smectic phases having the undecenyloxy group such as -(CH_(2))_(9)CH=CH_(2) (4-chloro-1,3-phenylene bis[4-(3-fluoro-4-undecenyloxyphenyliminomethyl) benzoate]; compound 14) showed antiferroelectric switching, and its value of spontaneous polarization was 250nC/㎠. On the other hand the smectic phases having the decanyloxy group such as -(CH_(2))_(9)CH_(3) (4-chloro-1,3- phenylene bis[4-(4-undecanyloxyphenyliminomethyl) ben- zoate], 4-chloro-1,3-phenylene bis[4-(3-fluoro-4-undecanyloxyphenyl- iminomethyl) benzoate], 4-chloro-1,3-phenylene bis[4-(3-chloro-4- undecanyloxyphenyliminomethyl) benzoate]; compound 4, 5, 6) showed antiferroelectric switching, and their values of spontaneous polarization were 250nC/㎠ for compound 4, 300nC/㎠ for compound 5, and 450nC/㎠ for compound 6, respectively. We could obtain the antiferroelectric phase with low isotropic temperature by varying the end group at the terminals of banana-shaped achiral molecules.