Structure control of poly(<i>p</i>-phenylene vinylene) in layer-by-layer films by deposition on a charged poly(<i>o</i>-methoxyaniline) cushion

Marletta, Alexandre; Silva, Silésia de Fátima Curcino da; Piovesan, Erick; Campos, K.R.; Silva, Hugo Santos; Souza, Nara C. de; Vega, Maria Letícia; Raposo, Maria; Constantino, Carlos J. L.; Silva, Raigna A.; Oliveira, Osvaldo N.

doi:10.1063/1.4798937

Cited by 2 publications

(1 citation statement)

References 25 publications

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“…This explains why the distribution of conjugated segments for PPV should be centered on n ≈ 3. The intra-and intermolecular interactions of PTHT and the defects arising from oxidative chemical groups such as carbonyl groups 20 hinder the formation of a linear sequence with higher conjugation degrees (n > 3). Therefore, the presence of a large number of PPV segments with short conjugation length creates many nonradiative pathways, thus explaining the low emission efficiency for these polymers.…”

Section: The Journal Ofmentioning

confidence: 99%

Kinetics of Thermal Conversion of Conjugated Polymers Investigated from Their Optical Absorption Spectra

2015

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We report on a phenomenological, theoretical model to calculate the rate constants and activation energies for the thermal conversion reactions from poly(xylylidene tetrahydrothiophenium chloride) (PTHT) into poly(p-phenylenevinylene) (PPV) using the optical absorption spectra of spin-coated films. The probabilities of electron transitions were calculated considering Franck-Condon states with a Gaussian distribution of conjugated segments and molecular excitons. The dependence on the conjugation degree (n) for the energy gap, transition dipole moment, and electron-phonon coupling were obtained semiempirically using published data for PPV. Fitting was performed for the C-C stretching of the aromatic ring 1550 cm(-1), for it is considered the most optically active. The isotherms for consumption and formation of PPV segments were fitted using a first-order and consecutive reactions, respectively. With this modeling we could identify the most probable reactions, where the formation of longer PPV segments n ≥ 3 occurs only via reactions from smaller conjugated segments (i.e., n = 1 and 2). The activation energies tend to decrease with longer conjugation lengths. Significantly, the modeling allows us to predict the conversion temperature and chemical composition yielding a predefined distribution of conjugated segments, which can be applied to any polymer undergoing thermal conversion, decomposition, or photo-oxidation.

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Section: The Journal Ofmentioning

confidence: 99%

Kinetics of Thermal Conversion of Conjugated Polymers Investigated from Their Optical Absorption Spectra

2015

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Layer-by-layer Nanoarchitectonics: Invention, Innovation, and Evolution

et al. 2013

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Materials fabrication with nanoscale structural precision based on bottom-up-type self-assembly has become more important in various current disciplines in chemistry including materials chemistry, organic chemistry, physical chemistry, analytical chemistry, biochemistry, colloid and surface chemistry, and supramolecular chemistry. Although the design of new materials based on nanoscale self-assembly is anticipated as a key concept, preparing complete three-dimensional structures at nanoscale precision remains a difficult target using current technologies. Rather, dimension-reduced approaches such as layering of two-dimensional nanostructures into precisely controlled lamellar nanomaterials are currently achievable. In particular, layer-by-layer (LbL) assembly is known as a highly versatile method for fabrication of controlled layered structures from various kinds of component materials using very simple, inexpensive, and rapid procedures. Therefore, fabrication of multilayer films through the LbL deposition process has attracted growing interest from various research communities. The high versatility and flexibility of LbL assembly is continuously creating new concepts, new materials, new procedures, and new applications. In this highlight review, we focus on nanoarchitectonics by LbL assembly. After an initial introduction on the invention and a brief history of the LbL assembly technique, innovations and the evolution of the technique are described based mainly on recent examples, which are categorized into two sections: (i) developments in methodology (technical, material, and phenomenological aspects with expansion of concept) and (ii) progress in applications (physical, chemical/biochemical, and biomedical applications).

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Structure control of poly(p-phenylene vinylene) in layer-by-layer films by deposition on a charged poly(o-methoxyaniline) cushion

Cited by 2 publications

References 25 publications

Kinetics of Thermal Conversion of Conjugated Polymers Investigated from Their Optical Absorption Spectra

Kinetics of Thermal Conversion of Conjugated Polymers Investigated from Their Optical Absorption Spectra

Layer-by-layer Nanoarchitectonics: Invention, Innovation, and Evolution

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