Synthesis and characterization of copolymaleimides containing 4-cyanobiphenyl-based side groups for nonlinear optical applications

✍ Scribed by Gangadhara; S. Ponrathnam; C. Noel; D. Reyx; F. Kajzar

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 273 KB
• Volume: 37
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(19990301)37:5<513::aid-pola1>3.0.co;2-c

✦ Synopsis

We report the synthesis of a nematic copolymer, P(CBMS-co-M 3 ), prepared by free radical polymerization of an equimolecular mixture of p-(4-cyanobiphenyl-4Ј-yloxy)methylstyrene (CBMS) and N-[3-(4-cyanobiphenyl-4Ј-yloxy)propyl]maleimide (M 3 ) and two isotropic alternating copolymers, P(S-alt-M n ) (n ϭ 3,6) prepared by chemical modification of poly(styrene-alt-maleimide), P(S-alt-M), by n-(4-cyanobiphenyl-4Ј-yloxy)alkan-1-ol. These copolymaleimides were characterized by NMR, DSC, and optical microscopy. Some corona poling experiments were performed and the second harmonic coefficients d 31 and d 33 were measured. It was shown that one can gain in net polar ordering by starting with a liquid crystalline system. The ratio d 33 /d 31 was much larger than 3, in agreement with the molecular statistical models for electric field poling of liquid crystals. At ambient conditions, changes of d 33 and d 31 are 15% over 325 days.