Ms. Angela Rotaru Profile

Angela Rotaru

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Publications (3)

Proceedings Article | 31 December 2020 Paper

Photophysics of poly(3,4-ethylenedioxythiophene) covered by permodified γ-cyclodextrin

A.-M. Resmerita, A. Costea, F. Farcas, A. Rotaru, A. Farcas

Proceedings Volume 11718, 117182K (2020) https://doi.org/10.1117/12.2572091

KEYWORDS: Polymerization, Atomic force microscopy, Samarium, Molecules, FT-IR spectroscopy, Molecular interactions, Absorption, Solids, Polymers

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Proceedings Article | 31 December 2018 Paper

The effect of the macrocyclic encapsulation on the photophysical properties of conjugated polymers

A. Farcas, A.-M. Resmerita, F. Farcas, A. Rotaru, M. Balan-Porcarasu, M. Asandulesa

Proceedings Volume 10977, 1097707 (2018) https://doi.org/10.1117/12.2322539

KEYWORDS: Luminescence, Polymers, Atomic force microscopy, Molecules, Molecular interactions, Optical properties, Organic light emitting diodes, Solid state electronics

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Proceedings Article | 14 December 2016 Paper

Synthesis and photophysics of conjugated azomethine polyrotaxanes

A.-M. Resmerita, F. Farcas, A. Rotaru, A. Farcas

Proceedings Volume 10010, 1001009 (2016) https://doi.org/10.1117/12.2242721

KEYWORDS: Polymers, Luminescence, Optoelectronics, Protactinium, Absorption, Molecules, Doping, Electrodes, Solids, Molecular interactions

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The photophysical properties of two polyazomethine polyrotaxanes (4•αCD and 4•TMS-αCD) composed of pyrene and triazole encapsulated into native and permodified α-cyclodextrin (αCD and TMS-αCD) cavities have been investigated and compared with those of the non-rotaxane 4 counterparts. Rotaxane formation results in improvements of the solubility in organic solvents, as well as better film forming ability combined with a high transparency. The polyrotaxane 4•TMS-αCD was soluble in toluene/DMF1/1 v/v mixture and displayed useful levels of thermal stability. The fluorescence spectroscopy of 4•αCD and 4•TMS-αCD shows an obvious blue shift both in excitation and emission spectra with respect to those of non-rotaxane counterparts. 4•TMS-αCD displays a continuous absorption spectrum, whereas the reference 4 does not show any absorption maximum, neither for its emission maximum, presumably because of its very low solubility in DMF. The improved fluorescence efficiency (ΦPL) of both polyrotaxanes is attributed to the hydrophobic micro-environment within αCD and TMS-αCD cavities. The surfaces of non-rotaxane 4 counterparts showed globular formations with an agglomeration tendency, while the encapsulated 4•αCD and 4•TMS-αCD rotaxane compounds exhibited smoother surfaces, comprised by smaller grains uniformly distributed on the surface of the solid films. The presence of the αCD and TMS-αCD in 4·αCD and 4•TMS-αCD polyrotaxanes affects the LUMO energy levels to a greater extent than its HOMO energy with respect to reference 4. The wetting properties of spin-coated film of 4•TMS-αCD in water (polar) and diiodomethane (apolar), indicates that TMS-αCD makes its surface more hydrophobic. The dispersive and polar components are lower than that of the reference compounds. The doping of the rotaxane structures with iodine (I2) indicated smaller improvements of electrical conductivity (σ) values, which presents a tradeoff with their better solubility, process ability, surface characteristics and ΦPL.

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