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Synthesis of NLO diacrylate monomers and their photocopolymerizations with LC diacrylate monomers in mixed liquid crystalline state
Author(s) -
Kato Masao,
Ohara Hiroki,
Fukuda Takashi,
Matsuda Hiro,
Nakanishi Hachiro
Publication year - 1998
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/(sici)1521-3935(19980501)199:5<881::aid-macp881>3.0.co;2-o
Subject(s) - monomer , liquid crystal , poling , crystallinity , materials science , polymer chemistry , polymer , phase (matter) , chemical engineering , organic chemistry , chemistry , composite material , ferroelectricity , engineering , optoelectronics , dielectric
The photocopolymerization (photocrosslinking) of mixed liquid crystals (LCs) consisting of LC diacrylate monomers and nonlinear optical (NLO) diacrylate monomers exhibiting no liquid crystallinity under contact poling at optimum temperature was investigated to obtain a thermally stable NLO polymeric material. Novel NLO monomers, BAASA and BAOSA , as well as LC monomers, BAOOB3 and PAOB , were synthesized and the liquid crystallinity of their mixed LCs was investigated. The affinity of BAOSA with the LC monomers is generally better than that of BAASA . LC mixtures prepared using BAOOB3 as LC matrix show only a smectic phase and do not respond to poling though fixation of the mixture by photocrosslinking occurs tightly. A PAOB matrix results in a nematic phase but not a smectic phase and the LC mixture responds not only to poling but also to photocopolymerization in the nematic phase. The photocrosslinking reaction of a BAOSA/PAOB (mole ratio 1/9) mixture under poling at 129°C (nematic phase) proceeds effectively and gives a thermally stable polymer film with a χ 33 (2) value of 1.2–1.7 × 10 −8 esu esu = electrostatic unit; 1 esu = 2.693 × 10 14 C 3 /J 2 . , while the polymer film formed by photocrosslinking at 140°C (isotropic phase) shows a one order lower χ 33 (2) value (3–5 × 10 −9 esu).