Study of the non-covalent interactions in Langmuir–Blodgett films: An interplay between π−π and dipole–dipole interactions

Tang, Zhexiong; Johal, Malkiat S.; Scudder, Paul H.; Caculitan, Niña; Magyar, Rudolph J; Tretiak, Sergei; Wang, Hsing‐Lin

doi:10.1016/j.tsf.2007.04.149

Cited by 29 publications

(20 citation statements)

References 20 publications

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“…6) as usually seen in LB films. Therefore, such small changes mean that the level of aggregation in these LB films [12,27] is smaller than the usual, probably because HPDod-MA, which does not show significant absorption over the entire UVVisible range, prevents a strong coupling between the azobenzene groups in the organized LB films.…”

Section: Langmuir-blodgett Films Propertiesmentioning

confidence: 97%

Molecular-level interactions of an azopolymer and poly(dodecylmethacrylate) in mixed Langmuir and Langmuir–Blodgett films for optical storage

Ceridório¹,

Balogh²,

Caseli

et al. 2010

Journal of Colloid and Interface Science

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a b s t r a c tThe applicability of azopolymers in optical storage can be extended through the use of nanostructured films produced with the Langmuir-Blodgett (LB) technique, but the film properties need to be optimized since these polymers generally do not form stable Langmuir films to be transferred onto solid substrates. Here, photoinduced birefringence was investigated for mixed Langmuir-Blodgett films from the homo-0 -nitroazobenzene (HPDR1-MA) and poly(dodecylmethacrylate) (HPDod-MA). The interactions between these polymers were studied in Langmuir and LB films. Surface pressure-area isotherms pointed to molecular-level interactions for proportions of 51 mf%, 41 mf% and 31 mf% of HPDR1-MA. Phase segregation was not apparent in the BAM images, in which the morphology of the blend film was clearly different from that of the Langmuir films of neat homopolymers. Through PM-IRRAS, we noted that the interaction between the azopolymer and HPDod-MA affected the orientation of carbonyl groups. Strong interactions for the mixture with 41 mf% of poly(dodecylmethacrylate) led to stable Langmuir films that were transferred onto solid supports as LB films. The photoinduced birefringence of 101-layer mixed LB films show features that make these films useful for optical storage, with the advantage of short writing times in comparison to other azopolymer films.

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Section: Langmuir-blodgett Films Propertiesmentioning

confidence: 97%

Molecular-level interactions of an azopolymer and poly(dodecylmethacrylate) in mixed Langmuir and Langmuir–Blodgett films for optical storage

Ceridório¹,

Balogh²,

Caseli

et al. 2010

Journal of Colloid and Interface Science

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“…The molecular packing might have also contributed to stabilization through van der Waals interactions. Johal et al35 reported that quantum chemical simulations suggested that the molecular packing of films has a complex relationship between molecular dipole moments, π–π interactions, and internal dipole moments of terminal groups.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, characterization, and photochemical properties of chromophores containing photoresponsive azobenzene and stilbene

Yang¹,

Wang²,

Wu³

2011

J of Applied Polymer Sci

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In this article, we describe the synthesis of two azobenzene and two stilbene-based diacetylene chromophores containing terminal electron-donating (AOCH 3 ) and electron-withdrawing (ANO 2 ) terminal groups with esterification reactions. The target compounds were characterized by NMR, X-ray diffraction (XRD), absorption, and photoluminescence spectroscopies. We investigated the structural effects of these photochromic compounds on the E-Z photoisomerization and 1,4-addition under UV irradiation. 4-[(4-Nitrophenyl)-diazenyl]phenyl pentacosa-10,12-diynoate, incorporating the electron-withdrawing nitro group (ANO 2 ), underwent the fastest rate of Z-to-E isomerization in darkness via a rotation mechanism. Our results demonstrate that self-assembled azobenzene Z isomers exhibited enhanced fluorescence under UV irradiation. XRD spectroscopy identified bilayer packing by the polydiacetylene films after 1,4-addition. Chromophores comprising the diacetylene group presented moderate photochromic stability upon 1,4-addition, changing from their original yellowish color to form a blue phase. These synthesized compounds may be useful in the development of new and unique functional materials that exhibit bistable photochromism.

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“…Tang et al [70] report a study on the influence of the terminal group of the modified amphiphilic azobenzene chromophore on the Langmuir-Blodgett monolayer and multilayer formation. The azobenzene NLO derivative was modified with various electron acceptor groups (acetyl, nitro, and cyano), and the self-assembling behavior of the resulted compounds was investigated, to produce monolayers and multilayers deposited onto hydrophobically treated quartz substrate.…”

Section: Langmuir-blodgett Filmsmentioning

confidence: 99%

“…Figure 11. The representation of monolayer structure with various packing densities for azobenzene NLO compounds bearing acetyl, nitro, and cyano groups (adapted with the permission from reference [70]). Figure 12.…”

Section: Langmuir-blodgett Filmsmentioning

confidence: 99%

Synthesis and Nonlinear Studies on Selected Organic Compounds in Nanostructured Thin Films

Cinteză¹,

Marinescu²

2018

Advanced Surface Engineering Research

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Organic compounds based on ferrocene, pyrazolone, and octahydroacridine exhibit high interest due to their unusual structure, with potential practical applications due to their special optical properties. Nonlinear optical (NLO) properties of some new synthesized derivatives are evaluated in relationship with the chemical structure by using DFT molecular modeling. In condensed state, ferrocene and other organic molecules were found in a staggered arrangement (D5d) as a nonpolar molecule, but the eclipsed (D5h) and twisted (D5) forms exhibit SHG capabilities. The molecular polarizability (α), first-order hyperpolarizabilities (β tot), dipole (μ tot), and quadrupole (Q) moments were computed. The NLO efficiency was assessed by the relationship between high (β tot)a n dl o wH O M O-L U M O energy gap. The nonlinear optical properties of some new synthesized compounds were evaluated in thin films with nanometric morphology obtained using various methods: Langmuir-Blodgett (LB) thin films, sol-gel deposition, and layer-by-layer deposition.

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Study of the non-covalent interactions in Langmuir–Blodgett films: An interplay between π−π and dipole–dipole interactions

Cited by 29 publications

References 20 publications

Molecular-level interactions of an azopolymer and poly(dodecylmethacrylate) in mixed Langmuir and Langmuir–Blodgett films for optical storage

Molecular-level interactions of an azopolymer and poly(dodecylmethacrylate) in mixed Langmuir and Langmuir–Blodgett films for optical storage

Synthesis, characterization, and photochemical properties of chromophores containing photoresponsive azobenzene and stilbene

Synthesis and Nonlinear Studies on Selected Organic Compounds in Nanostructured Thin Films

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