Synthesis and characterization of novel crosslinkable polymers with a nonlinear optical chromophore as a pendant group

Abstract

New crosslinkable polymers with a nonlinear optical (NLO) active chromophore as a pendant group were synthesized by condensation chain polymerization via palladium-catalyzed carbon-carbon coupling reactions. The polymerization yields were almost quantitative between the diiodobenzene (DIB) and diethyldipropargyl malonate (DEDPM) or 4-(dimethylamino)-4Ј-(6-dipropargylacetoxypropylsulfonyl)stilbene (DASS-6) monomers. To improve the molecular weight and mechanical properties of the NLO active polymer, we carried out the copolymerization with DIB and DASS-6 with various feed ratios of DEDPM. The resulting polymers were soluble in organic solvents and spun-cast onto indium tin oxide-coated glass substrates to make thin films. The molecular structures of the resulting polymers were characterized with various instrumental methods to confirm the carbon-carbon coupling reactions between the DIB and diacetylene monomers. The absorption of the ultraviolet-visible spectrum of the resulting polymers was drastically reduced after thermal curing at 160°C because of the crosslinking of the reactive acetylene group in the polymer backbone. The electrooptic coefficient (r 33 ) measured at 1.3 m ranged from 7 to 15 pm/V.

New polyurethanes and polyesters for second‐order nonlinear optical applications

“…Two factors can occur together to improve the bulk NLO properties of a polymer: the good orientation of dipolar chromophores obtained with poling and the possibility of freezing them in their positions after poling. This can be achieved with a successive crosslinking reaction 7–11. Polymers with high glass‐transition temperatures can offer versatile and effective alternatives,12–16 but these polymers often exhibit overly rigid chains, and so it is quite difficult to process them for subsequent applications.…”

Synthesis and Optical Properties of Poly(2-substituted-9,9-dipropargylfluorene)s

“…Many of these linear polymers can be cured (crosslinked) via the photochemical or thermal reaction of the diacetylene linkages [21]. New crosslinkable acetylenic polymers were prepared by the palladium-catalyzed carbon-carbon coupling reactions between the diiodobenzene and diethyldipropargyl malonate in quantitative yield [27]. The thermal curing behaviors of the resulting materials are related to the polymer structures [28].…”

Transition‐metal‐catalyzed conjugated polymers of 1,6‐heptadiyne derivatives in supercritical carbon dioxide

“…Hence, it is difficult to use acetylene derivatives as active materials in optoelectronic devices. Among the various acetylenic monomers, 1,6‐heptadiyne and its homologues are known to produce soluble π‐conjugated polymers in organic solvents and to endow multifunctional properties such as liquid‐crystalline conducting polymers14–16 and nonlinear optical properties17 by introducing the functional moiety into the 4‐position of 1,6‐heptadiyne backbones.…”