Quadratic nonlinear optical and preliminary piezoelectric investigation of crosslinked samples obtained from a liquid chromophore

Abstract

A push–pull chromophore has been synthesized, which is liquid at room temperature and can be crosslinked owing to the presence of two methacrylate moieties. Thin films of the chromophore have been prepared by spin coating, and they have been simultaneously crosslinked and poled under strong electric field. On the poled crosslinked films, the quadratic nonlinear optical (NLO) characterization was performed through nonresonant second harmonic generation measurements at 1368 nm as the fundamental wavelength, yielding a fairly good d33 value of 46 pm/V, with retention of 80% of that value after 2 months at 85 °C. Following the theoretical issue that the quadratic NLO and piezoelectric tensors of a material have the same symmetry properties, and exploiting the easy processing of the chromophore in the liquid phase, we have prepared poled crosslinked samples of the chromophore suitable for piezoelectric tests that were performed using a commercial piezoceramic sample as the reference. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012

Preparation of transparent PMMA/Fe(IO3)3 nanocomposite films from microemulsion polymerization

“…Development of printable inks with noncentrosymmetric nanofillers could also be relevant in the emerging field of printed electronics if addition of nonlinear optical properties on flexible substrates and smart foils are of interest. In this respect however, full organic polymers obtained after crosslinking of push‐pull chromophores are to date more appropriate in terms of material performances, as recently demonstrated …”

2-(4-Methylphenyl)-6-nitro-1,3-benzoxazole

“…For general information on heterocycles in organic electronics and optoelectronics, see: Dalton (2002); Heeger (2010). For heterocycle-based semiconductors, optoelectronic and piezoelectric materials, see: ; Centore, Ricciotti et al (2012); Centore, Concilio et al (2012). For structural and theoretical analysis of conjugation in heterocycle-based organic molecules, see: Carella, Centore, Fort et al (2004); Gainsford et al (2008).…”

2-Cyano-5-({4-[N-methyl-N-(2-hydroxyethyl)amino] phenyl}diazenyl)pyridine

“…For the CSD see: Allen (2002). For the synthesis of related compounds, see: Bruno et al (2002); Centore et al (2007); Centore et al (2012). 191 parameters H-atom parameters constrained Á max = 0.14 e Å À3 Á min = À0.21 e Å À3 Table 1 Hydrogen-bond geometry (Å , ).…”

“…Moreover, the cyano group is attached to an electron poor pyridine ring, and this should increase the electron withdrawing character. This compound has been used in the synthesis of cross-linked systems showing both piezoelectric and quadratic NLO behaviour (Centore et al, 2012).…”

“…(I) was prepared by diazotization of 5-amino-2-cyanopyridine followed by coupling with N-methyl-N-(2-hydroxyethyl)aniline. The procedure of diazo-coupling is analogous to that we have already described for the synthesis of similar diazochromophores (Bruno et al, 2002;Centore et al, 2007;Centore et al, 2012). Purification of (I) was obtained by recrystallization from ethanol.…”