Aurica Farcas - Profile on Academia.edu (original) (raw)
Papers by Aurica Farcas
The straightforward approach of tuning the photoluminescence and electrical properties of encapsulated PEDOT end-capped by pyrene
Journal of Molecular Liquids
Host – quest complexes between cyclodextrins and functional polysiloxanes
Photophysics of poly(3,4-ethylenedioxythiophene) covered by permodified γ-cyclodextrin
Poly(3,4-ethylenedioxythiophene/permethylated γ-cyclodextrin) polyrotaxane (PEDOT∙TMγCD) having b... more Poly(3,4-ethylenedioxythiophene/permethylated γ-cyclodextrin) polyrotaxane (PEDOT∙TMγCD) having bulky triphenylmethyl as stoppers was synthesized by the chemical oxidation of 3,4-ethylenedioxythiophene (EDOT) as an inclusion complex with 2,3,6-tri-O-methyl γ-cyclodextrin (TMγCD) (EDOT∙TMγCD) with a five-fold excess of iron (III) chloride oxidant over the stoichiometric amount in water. For a comparison, the reference PEDOT was synthesized under the same experimental conditions. The chemical structures of the synthesized compounds were proved by FT-IR and NMR spectroscopies. The coverage ratio of the EDOT and PEDOT backbones was found to be of 80.0 % and 43.7 %, respectively. Differential scanning calorimetry (DSC) studies of both PEDOT and PEDOT∙TMγCD samples showed no crystallization or melting peaks in the range 20-200 °C. The PEDOT∙TMγCD as dark-green powders was enough soluble in acetone, dichloromethane, CHCl3 and THF compared with those of the reference PEDOT. The optical prop...
Macromolecular Chemistry and Physics, 2020
The effect of 10 wt% polypyrrole (PPy) incorporation on the evolution of conductivity, dielectric... more The effect of 10 wt% polypyrrole (PPy) incorporation on the evolution of conductivity, dielectric constant, and dielectric loss by varying the temperature and frequency of amine‐terminated poly(ethylene glycol)/randomly methylated β‐cyclodextrins (PEGBA/RAMEB) polyrotaxane cross‐linked with 1,6‐hexamethylene diisocyanate is reported. This composite material shows an enhanced dielectric constant value of 25.6 (at 10 Hz) compared with 8.3 of the pure cross‐linked PEGBA/RAMEB polyrotaxane. The values of the dielectric constant are consistent with the dielectric loss and conductivity results. The composite material shows that the direct current conductivity (σDC) at lower temperature is independent of frequency. In comparison, at higher temperature, σDC is dependent on frequency, denoting that the conductivity of the composite material is a thermally activated process. Moreover, the presence of PPy significantly influences the morphology of the cross‐linked PEGBA/RAMEB polyrotaxane. Add...
European Polymer Journal, 2019
New supramolecular networks were synthesized by cross-linking reaction of polyethylene glycol (PE... more New supramolecular networks were synthesized by cross-linking reaction of polyethylene glycol (PEG) polyrotaxane with a 10 wt% of poly(3,4-ethylenedioxythiophene) (PEDOT) polyrotaxanes. For comparison purpose, a cross-linked material of PEG polyrotaxane with PEDOT non-rotaxane counterpart was also synthesized under similar conditions. The chemical structures of these compounds were evidenced by using ATR-FT-IR and WAXS. The thermal stability was evaluated by TGA analysis. The evolution of dielectric constant and dielectric loss by varying the temperature and frequency, and conductivity of the investigated compounds were compared with those of the pure cross-linked material. The value of the dielectric constant of pure cross-linked film at 10 Hz frequency is 2.6, whereas for the film with PEDOT-βCD polyrotaxane incorporated into the matrix increases to 32, which are consistent with the dielectric loss and conductivity results. At the lower temperature region, the alternating current conductivity (σ AC ) increases monotonically with increasing of frequency , denoting that the conductivity of short-range species is predominant. When the temperature increases, the direct current conductivity (σ DC ), corresponding to the long-range mobility of the free charges is independent of the frequency.
A. Farcas, N. Marangoci, A. Fifere, M. Pinteala, V. Harabagiu, B.C. Simionescu Polyrotaxanes with cyclodextrins Nova Science Publishers, New Trends in Nonionic (Co) Polymers and Hybrids, Ed. E.S. Dragan, pp. 53-77, 2006, ISBN: 1- 60021-051-1
![Research paper thumbnail of Photophysical Studies of Poly(3,4-Ethylenedioxythiophene/Cucurbit[7]uril) Polypseudorotaxane and Polyrotaxane by Transient Absorption and Time-Resolved Fluorescence Spectroscopy](https://attachments.academia-assets.com/123560894/thumbnails/1.jpg)
](ECSA-9, Nov 1, 2022
The UV-Vis absorption, fluorescence, and phosphorescence spectra of poly (3,4ethylenedioxythiophe... more The UV-Vis absorption, fluorescence, and phosphorescence spectra of poly (3,4ethylenedioxythiophene/cucurbit[7]uril), polypseudorotaxane (1), and polyrotaxane (2) in water and acetonitrile solutions were investigated. To achieve a deeper insight into the optical properties, the transient absorptions, lifetimes, and quantum yields have been carried out on compounds 1 and 2. The transient absorption demonstrated an excited-state processes and involvement of high energy electronic states (S n > 1). The transient absorption map in acetonitrile revealed at 210, 240, 300, and 315 nm a ground states bleaching bands (GSB), whereas at shorter wavelengths an absorption in excited states (ESA) and more than one excited state (S n > 1). At 382 and 420 nm wavelength two negative bands appeared which were assigned to the stimulated emissions (SE). At longer wavelengths, i.e., 605, 625, and 710 nm, other stimulated emissions appeared that are probably a result of the triplet manifold, confirming their phosphorescence properties. Additionally, the quantum yield with absolute values in the range 5-25%, and phosphorescence lifetime with values in the range 1-9 µs were evaluated.
Materials
Two poly(3,4-ethylenedioxythiophene) polyrotaxanes (PEDOT∙TMe-βCD and PEDOT∙TMe-γCD) end-capped b... more Two poly(3,4-ethylenedioxythiophene) polyrotaxanes (PEDOT∙TMe-βCD and PEDOT∙TMe-γCD) end-capped by pyrene (Py) were synthesized by oxidative polymerization of EDOT encapsulated into TMe-βCD or TMe-γCD cavities with iron (III) chloride (FeCl3) in water and chemically characterized. The effect of TMe-βCD or TMe-γCD encapsulation of PEDOT backbones on the molecular weight, thermal stability, and solubility were investigated in depth. UV–vis absorption, fluorescence (FL), phosphorescence (PH), quantum efficiencies, and lifetimes in water and acetonitrile were also explored, together with their surface morphology and electrical properties. Furthermore, dynamic light scattering was used to study the hydrodynamic diameter (DH) and z-potential (ZP-ζ) of the water soluble fractions of PEDOT∙TMe-βCD and PEDOT∙TMe-γCD. PEDOT∙TMe-βCD and PEDOT∙TMe-γCD exhibited a sharp monodisperse peak with a DH of 55 ± 15 nm and 122 ± 32 nm, respectively. The ZP-ζ value decreased from −31.23 mV for PEDOT∙TMe-...
Materials
New composite materials were prepared via cross-linking of polyethylene glycol/2-hydroxypropyl-β-... more New composite materials were prepared via cross-linking of polyethylene glycol/2-hydroxypropyl-β-cyclodextrins polyrotaxane (PEG/HPβCD) and polyisoprene/HPβCD semi-polyrotaxane (PI/HPβCD SR) with 1,6-hexamethylene diizocyanate (HMDI). Advanced instrumental methods (such WAXS (wide angle X-ray scattering), AFM (atomic force microscopy), SEM (scanning electron microscopy), and thermal and dynamic vapor sorption) were employed for the structural, morphological and thermal characterization of the resulting composite materials. The roughness parameters calculated using AFM indicate a smoother surface for the composite material with 10 wt% of PI/HPβCD SR, denoting that a homogeneous film was obtained. SEM analysis reveals porous morphologies for both composite materials and the pore sizes increase with the increasing concentration of PI/HPβCD SR in the matrix. Dynamic vapor sorption/desorption measurements and type IV isotherms confirmed the hydrophilic and porous materials, which are in ...
Phosphorus, Sulfur, and Silicon and the Related Elements, 2019
This work deals with the effect of chemical structure and iodine doping on electro-optical charac... more This work deals with the effect of chemical structure and iodine doping on electro-optical characteristics of different polysilanes in the solid state. The properties of polymethylphenylsilane homopolymer were compared with those of polysilane copolymers containing diphenylsilylene structural units associated with either methylhydrogen-or methylphenylsilylene moieties. Their optical parameters, such as Urbach energy and optical band gap, were evaluated using the method proposed by Tauc. The forbidden gap values for the studied polysilanes are reduced after doping from 3.22-3.46 eV to 2.47-2.64 eV, while the electrical conductivities were found in the range of 6.2 10 À11-1.2 10 À8 S/cm for pristine samples, and increased by 2-3 orders of magnitude following their doping, depending on the nature/content of the organic substituents attached to the silicon main chain. A simple mathematical approach starting from Tauc classical theory was used to establish allowed direct optical transitions for both undoped and doped polysilane samples. The obtained data indicated that the polysilane films with a high content of phenyl side groups presented the best properties for their use in electro-optical applications.
e-Polymers, 2006
This paper is devoted to the preparation and characterization of new phenanthroline-triether copo... more This paper is devoted to the preparation and characterization of new phenanthroline-triether copolymers with rotaxane architecture by reaction of complexes of α- or β- cyclodextrin and tri(ethylene glycol) ditosylate with 2,9-di(4-hydroxyphenyl)-1,10- phenanthroline, which is large enough to prevent dethreading of cyclodextrin molecules. Comparative
Polymer Bulletin, 1994
The synthesis of three Schiff-base type monomers containing pyrrole units was performed. Their po... more The synthesis of three Schiff-base type monomers containing pyrrole units was performed. Their polymerization was carried out by chemical oxidation with (NH4)2S208. Some preliminary thermal and electrical properties were determined.
![Research paper thumbnail of Effect of Rotaxane Formation on the Photophysical, Morphological, and Adhesion Properties of Poly[2,7-(9,9-dioctylfluorene)-alt -(5,5'-bithiophene)] Main-Chain Polyrotaxanes](https://attachments.academia-assets.com/106695081/thumbnails/1.jpg)
](Macromolecular Chemistry and Physics, 2011
Effect of Rotaxane Formation on the Photophysical www.mcp-journal.de UEFISCSU, project number PNI... more Effect of Rotaxane Formation on the Photophysical www.mcp-journal.de UEFISCSU, project number PNII-IDEI cod 998/2008, and SENAN code 12-109/2008. IG and WMN would like to thank the Deutsche Forschungsgemeinschaft (DFG, NA 686/6) and the Fonds der Chemischen Industrie for financial support. AF thanks the ICTS program and the Center for Functional Materials and Nano-molecular Science (NanoFun) at Jacobs University for supporting a research stay. Helpful cooperation with Dr. Nathalie Jarroux (from the Universitite d'Evry, France) is acknowledged.
Supramacromolecular self-assembly: Chain extension, star and block polymers via pseudorotaxane formation from well-defined end-functionalized polymers
Journal of Polymer Science Part A: Polymer Chemistry, 2009
Skip to Main Content. ...
[
Poly[2,7-(9,9-dioctylfluorene)-alt-(5,5′-bithiophene/permethylated β-cyclodextrin) main-chain polyrotaxane: Synthesis, characterization and surface morphology
European Polymer Journal, 2014
ABSTRACT Poly[2,7-(9,9-dioctylfluorene)-alt-(5,5′-bithiophene/permethylated β-cyclodextrin) (3·PM... more ABSTRACT Poly[2,7-(9,9-dioctylfluorene)-alt-(5,5′-bithiophene/permethylated β-cyclodextrin) (3·PMeβCD) main-chain polyrotaxane was synthesized according to a Suzuki-type aryl-aryl coupling protocol, by reacting 9,9-dioctylfluorene-2,7-trimethylene diborate (1) with an inclusion complex of 5,5′-dibromo-2,2′-bithiophene (2)/permethylated-βCD (PMeβCD) (2·PMeβCD). The complexation ability of PMeβCD molecule towards monomer 2 was confirmed by MM+ and PM3 quantum-mechanics semi-empirical methods, ESI-MS, (ESI) MS/MS analysis, as well as FTIR and 1H-NMR spectroscopy. A conjugated polyrotaxane copolymer with PMeβCD/structural unit ratio of about 1/3 and the number average molecular weight (Mn) value of 30600 was obtained by 1H-NMR spectroscopy and gel permeation chromatography, respectively. The thermal, optical, surface morphology and the adhesion characteristics were investigated and compared to those of the non-rotaxane counterpart poly[2,7-(9,9-dioctylfluorene)-alt-(5,5′-bithiophene) (3).
Thermal Analysis and Theoretical Study of [alpha]-Cyclodextrin Azomethine [2]-Rotaxane Formation by Semi-Empirical Method Pm3
Chemical Physics …, 2011
... OF - CYCLODEXTRIN AZOMETHINE [2]-ROTAXANE FORMATION BY SEMI-EMPIRICAL METHOD PM3 Aurica Farca... more ... OF - CYCLODEXTRIN AZOMETHINE [2]-ROTAXANE FORMATION BY SEMI-EMPIRICAL METHOD PM3 Aurica Farcas a*1 , Adrian Fifere a , Iuliana Stoica a , Flavian Farcas b , Ana-Maria Resmerita aa P. Poni Institute of Macromolecular Chemistry, 41A Gr. Ghica Voda Alley ...
Electro-optical properties of aromatic oligoazomethine/permethylated α-cyclodextrin main-chain polyrotaxanes
Chemical Physics Letters, 2014
ABSTRACT The effect of oligoazomethines (OA) encapsulation into the cavity of permethylated α-cyc... more ABSTRACT The effect of oligoazomethines (OA) encapsulation into the cavity of permethylated α-cyclodextrin on the electro-optical properties was investigated. The polyrotaxane (OA-Rot) formation leads to distinct improvements in the solubility and film forming ability, as well as photophysical and morphological properties, compared with OA unthreaded analogues. The 2D and 3D AFM images of the OA-Rot film showed a smoother and uniform surface. In addition, the HOMO/LUMO energy levels, as well as the energy band gap of OA-Rot are slightly lower than OA counterpart. As expected, doping of the rotaxane structures with iodine showed a smaller enhancement of the electrical conductivity.
Synthesis and characterization of low molecular weight poly(1-butene) macromolecules prepared using metallocene catalysts
Applied Catalysis A: General, 2013
Abstract Poly(1-butene) low molecular weight macromolecules with molecular weights within 1000–20... more Abstract Poly(1-butene) low molecular weight macromolecules with molecular weights within 1000–20,000 g mol −1 and isotacticities around 50–90% were prepared by the polymerization of 1-butene in liquid phase with n-butane as solvent using two metallocene catalysts: rac-dimethyl-silyl-bis-(2-methyl-4,5-benzoindenyl)zirconium dichloride (A) and rac-dimethyl-silyl-bis-(2-methylindenyl)zirconium dichloride (B). Catalyst A showed higher yields and productivities than catalyst B, as well as better isotacticity values, which were ascribed to the presence of an additional aryl substituent in the indenyl moiety which increases its stability and hinders deactivation phenomena by aggregation. Kinetic experiments with catalyst A showed a continuous increase in conversion along the time so no strong deactivation was observed. With catalyst A, an increase in the hydrogen pressure at 75 °C up to 6.0 bar led towards low molecular weight macromolecules with 3000–4000 g mol −1 and a isotacticity of 75–80%. An enhancement in temperature up to 105 °C decreased the yields, molecular weights and isotacticity for both catalysts. Additionally, increasing the hydrogen partial pressure to 1.0 bar at 95 and 105 °C decreased the molecular weight within the 3000–5500 g mol −1 range. XRD patterns of the majority of low molecular weight macromolecules showed the presence of mixed phases, although some low molecular weight macromolecules with pure phase I (twined hexagonal) were obtained. Additionally, the DSC thermograms showed a decrease in the melting temperatures of the crystalline phases of poly(1-butene) low molecular weight macromolecules with regard to the corresponding ones of poly(1-butene) polymers ( M w > 100,000 g mol −1 ), due to their lower molecular weight.
The present manuscript reports an overview of the design and conceptual approaches to the synthes... more The present manuscript reports an overview of the design and conceptual approaches to the synthesis of rotaxaconjugated polymers (R-CP), such as aromatic polyazomethines, alternating or random polyfluorene copolymers encapsulated inside native CD cavities. Their synthesis correlated with an overview of the photophysical properties, surface morphology and electrochemical behaviours, which are advantageous for the generation of active layers in organic electronic devices, are considered in this review.
Molecules
Herein, we report the synthesis of inclusion complexes (ICs) based on 3,4-ethylenedioxythiophene ... more Herein, we report the synthesis of inclusion complexes (ICs) based on 3,4-ethylenedioxythiophene (EDOT) with permethylated β-cyclodextrins (TMe-βCD) and permethylated γ-cyclodextrins (TMe-γCD) host molecules. To prove the synthesis of such ICs, molecular docking simulation, UV-vis titrations in water, 1H-NMR, and H-H ROESY, as well as matrix-assisted laser desorption ionization mass spectroscopy (MALDI TOF MS) and thermogravimetric analysis (TGA) were carried out on each of the EDOT∙TMe-βCD and EDOT∙TMe-γCD samples. The results of computational investigations reveal the occurrence of hydrophobic interactions, which contribute to the insertion of the EDOT guest inside the macrocyclic cavities and a better binding of the neutral EDOT to TMe-βCD. The H-H ROESY spectra show correlation peaks between H-3 and H-5 of hosts and the protons of the guest EDOT, suggesting that the EDOT molecule is included inside the cavities. The MALDI TOF MS analysis of the EDOT∙TMe-βCD solutions clearly rev...
The straightforward approach of tuning the photoluminescence and electrical properties of encapsulated PEDOT end-capped by pyrene
Journal of Molecular Liquids
Host – quest complexes between cyclodextrins and functional polysiloxanes
Photophysics of poly(3,4-ethylenedioxythiophene) covered by permodified γ-cyclodextrin
Poly(3,4-ethylenedioxythiophene/permethylated γ-cyclodextrin) polyrotaxane (PEDOT∙TMγCD) having b... more Poly(3,4-ethylenedioxythiophene/permethylated γ-cyclodextrin) polyrotaxane (PEDOT∙TMγCD) having bulky triphenylmethyl as stoppers was synthesized by the chemical oxidation of 3,4-ethylenedioxythiophene (EDOT) as an inclusion complex with 2,3,6-tri-O-methyl γ-cyclodextrin (TMγCD) (EDOT∙TMγCD) with a five-fold excess of iron (III) chloride oxidant over the stoichiometric amount in water. For a comparison, the reference PEDOT was synthesized under the same experimental conditions. The chemical structures of the synthesized compounds were proved by FT-IR and NMR spectroscopies. The coverage ratio of the EDOT and PEDOT backbones was found to be of 80.0 % and 43.7 %, respectively. Differential scanning calorimetry (DSC) studies of both PEDOT and PEDOT∙TMγCD samples showed no crystallization or melting peaks in the range 20-200 °C. The PEDOT∙TMγCD as dark-green powders was enough soluble in acetone, dichloromethane, CHCl3 and THF compared with those of the reference PEDOT. The optical prop...
Macromolecular Chemistry and Physics, 2020
The effect of 10 wt% polypyrrole (PPy) incorporation on the evolution of conductivity, dielectric... more The effect of 10 wt% polypyrrole (PPy) incorporation on the evolution of conductivity, dielectric constant, and dielectric loss by varying the temperature and frequency of amine‐terminated poly(ethylene glycol)/randomly methylated β‐cyclodextrins (PEGBA/RAMEB) polyrotaxane cross‐linked with 1,6‐hexamethylene diisocyanate is reported. This composite material shows an enhanced dielectric constant value of 25.6 (at 10 Hz) compared with 8.3 of the pure cross‐linked PEGBA/RAMEB polyrotaxane. The values of the dielectric constant are consistent with the dielectric loss and conductivity results. The composite material shows that the direct current conductivity (σDC) at lower temperature is independent of frequency. In comparison, at higher temperature, σDC is dependent on frequency, denoting that the conductivity of the composite material is a thermally activated process. Moreover, the presence of PPy significantly influences the morphology of the cross‐linked PEGBA/RAMEB polyrotaxane. Add...
European Polymer Journal, 2019
New supramolecular networks were synthesized by cross-linking reaction of polyethylene glycol (PE... more New supramolecular networks were synthesized by cross-linking reaction of polyethylene glycol (PEG) polyrotaxane with a 10 wt% of poly(3,4-ethylenedioxythiophene) (PEDOT) polyrotaxanes. For comparison purpose, a cross-linked material of PEG polyrotaxane with PEDOT non-rotaxane counterpart was also synthesized under similar conditions. The chemical structures of these compounds were evidenced by using ATR-FT-IR and WAXS. The thermal stability was evaluated by TGA analysis. The evolution of dielectric constant and dielectric loss by varying the temperature and frequency, and conductivity of the investigated compounds were compared with those of the pure cross-linked material. The value of the dielectric constant of pure cross-linked film at 10 Hz frequency is 2.6, whereas for the film with PEDOT-βCD polyrotaxane incorporated into the matrix increases to 32, which are consistent with the dielectric loss and conductivity results. At the lower temperature region, the alternating current conductivity (σ AC ) increases monotonically with increasing of frequency , denoting that the conductivity of short-range species is predominant. When the temperature increases, the direct current conductivity (σ DC ), corresponding to the long-range mobility of the free charges is independent of the frequency.
A. Farcas, N. Marangoci, A. Fifere, M. Pinteala, V. Harabagiu, B.C. Simionescu Polyrotaxanes with cyclodextrins Nova Science Publishers, New Trends in Nonionic (Co) Polymers and Hybrids, Ed. E.S. Dragan, pp. 53-77, 2006, ISBN: 1- 60021-051-1
ECSA-9, Nov 1, 2022
The UV-Vis absorption, fluorescence, and phosphorescence spectra of poly (3,4ethylenedioxythiophe... more The UV-Vis absorption, fluorescence, and phosphorescence spectra of poly (3,4ethylenedioxythiophene/cucurbit[7]uril), polypseudorotaxane (1), and polyrotaxane (2) in water and acetonitrile solutions were investigated. To achieve a deeper insight into the optical properties, the transient absorptions, lifetimes, and quantum yields have been carried out on compounds 1 and 2. The transient absorption demonstrated an excited-state processes and involvement of high energy electronic states (S n > 1). The transient absorption map in acetonitrile revealed at 210, 240, 300, and 315 nm a ground states bleaching bands (GSB), whereas at shorter wavelengths an absorption in excited states (ESA) and more than one excited state (S n > 1). At 382 and 420 nm wavelength two negative bands appeared which were assigned to the stimulated emissions (SE). At longer wavelengths, i.e., 605, 625, and 710 nm, other stimulated emissions appeared that are probably a result of the triplet manifold, confirming their phosphorescence properties. Additionally, the quantum yield with absolute values in the range 5-25%, and phosphorescence lifetime with values in the range 1-9 µs were evaluated.
Materials
Two poly(3,4-ethylenedioxythiophene) polyrotaxanes (PEDOT∙TMe-βCD and PEDOT∙TMe-γCD) end-capped b... more Two poly(3,4-ethylenedioxythiophene) polyrotaxanes (PEDOT∙TMe-βCD and PEDOT∙TMe-γCD) end-capped by pyrene (Py) were synthesized by oxidative polymerization of EDOT encapsulated into TMe-βCD or TMe-γCD cavities with iron (III) chloride (FeCl3) in water and chemically characterized. The effect of TMe-βCD or TMe-γCD encapsulation of PEDOT backbones on the molecular weight, thermal stability, and solubility were investigated in depth. UV–vis absorption, fluorescence (FL), phosphorescence (PH), quantum efficiencies, and lifetimes in water and acetonitrile were also explored, together with their surface morphology and electrical properties. Furthermore, dynamic light scattering was used to study the hydrodynamic diameter (DH) and z-potential (ZP-ζ) of the water soluble fractions of PEDOT∙TMe-βCD and PEDOT∙TMe-γCD. PEDOT∙TMe-βCD and PEDOT∙TMe-γCD exhibited a sharp monodisperse peak with a DH of 55 ± 15 nm and 122 ± 32 nm, respectively. The ZP-ζ value decreased from −31.23 mV for PEDOT∙TMe-...
Materials
New composite materials were prepared via cross-linking of polyethylene glycol/2-hydroxypropyl-β-... more New composite materials were prepared via cross-linking of polyethylene glycol/2-hydroxypropyl-β-cyclodextrins polyrotaxane (PEG/HPβCD) and polyisoprene/HPβCD semi-polyrotaxane (PI/HPβCD SR) with 1,6-hexamethylene diizocyanate (HMDI). Advanced instrumental methods (such WAXS (wide angle X-ray scattering), AFM (atomic force microscopy), SEM (scanning electron microscopy), and thermal and dynamic vapor sorption) were employed for the structural, morphological and thermal characterization of the resulting composite materials. The roughness parameters calculated using AFM indicate a smoother surface for the composite material with 10 wt% of PI/HPβCD SR, denoting that a homogeneous film was obtained. SEM analysis reveals porous morphologies for both composite materials and the pore sizes increase with the increasing concentration of PI/HPβCD SR in the matrix. Dynamic vapor sorption/desorption measurements and type IV isotherms confirmed the hydrophilic and porous materials, which are in ...
Phosphorus, Sulfur, and Silicon and the Related Elements, 2019
This work deals with the effect of chemical structure and iodine doping on electro-optical charac... more This work deals with the effect of chemical structure and iodine doping on electro-optical characteristics of different polysilanes in the solid state. The properties of polymethylphenylsilane homopolymer were compared with those of polysilane copolymers containing diphenylsilylene structural units associated with either methylhydrogen-or methylphenylsilylene moieties. Their optical parameters, such as Urbach energy and optical band gap, were evaluated using the method proposed by Tauc. The forbidden gap values for the studied polysilanes are reduced after doping from 3.22-3.46 eV to 2.47-2.64 eV, while the electrical conductivities were found in the range of 6.2 10 À11-1.2 10 À8 S/cm for pristine samples, and increased by 2-3 orders of magnitude following their doping, depending on the nature/content of the organic substituents attached to the silicon main chain. A simple mathematical approach starting from Tauc classical theory was used to establish allowed direct optical transitions for both undoped and doped polysilane samples. The obtained data indicated that the polysilane films with a high content of phenyl side groups presented the best properties for their use in electro-optical applications.
e-Polymers, 2006
This paper is devoted to the preparation and characterization of new phenanthroline-triether copo... more This paper is devoted to the preparation and characterization of new phenanthroline-triether copolymers with rotaxane architecture by reaction of complexes of α- or β- cyclodextrin and tri(ethylene glycol) ditosylate with 2,9-di(4-hydroxyphenyl)-1,10- phenanthroline, which is large enough to prevent dethreading of cyclodextrin molecules. Comparative
Polymer Bulletin, 1994
The synthesis of three Schiff-base type monomers containing pyrrole units was performed. Their po... more The synthesis of three Schiff-base type monomers containing pyrrole units was performed. Their polymerization was carried out by chemical oxidation with (NH4)2S208. Some preliminary thermal and electrical properties were determined.
Macromolecular Chemistry and Physics, 2011
Effect of Rotaxane Formation on the Photophysical www.mcp-journal.de UEFISCSU, project number PNI... more Effect of Rotaxane Formation on the Photophysical www.mcp-journal.de UEFISCSU, project number PNII-IDEI cod 998/2008, and SENAN code 12-109/2008. IG and WMN would like to thank the Deutsche Forschungsgemeinschaft (DFG, NA 686/6) and the Fonds der Chemischen Industrie for financial support. AF thanks the ICTS program and the Center for Functional Materials and Nano-molecular Science (NanoFun) at Jacobs University for supporting a research stay. Helpful cooperation with Dr. Nathalie Jarroux (from the Universitite d'Evry, France) is acknowledged.
Supramacromolecular self-assembly: Chain extension, star and block polymers via pseudorotaxane formation from well-defined end-functionalized polymers
Journal of Polymer Science Part A: Polymer Chemistry, 2009
Skip to Main Content. ...
[
Poly[2,7-(9,9-dioctylfluorene)-alt-(5,5′-bithiophene/permethylated β-cyclodextrin) main-chain polyrotaxane: Synthesis, characterization and surface morphology
European Polymer Journal, 2014
ABSTRACT Poly[2,7-(9,9-dioctylfluorene)-alt-(5,5′-bithiophene/permethylated β-cyclodextrin) (3·PM... more ABSTRACT Poly[2,7-(9,9-dioctylfluorene)-alt-(5,5′-bithiophene/permethylated β-cyclodextrin) (3·PMeβCD) main-chain polyrotaxane was synthesized according to a Suzuki-type aryl-aryl coupling protocol, by reacting 9,9-dioctylfluorene-2,7-trimethylene diborate (1) with an inclusion complex of 5,5′-dibromo-2,2′-bithiophene (2)/permethylated-βCD (PMeβCD) (2·PMeβCD). The complexation ability of PMeβCD molecule towards monomer 2 was confirmed by MM+ and PM3 quantum-mechanics semi-empirical methods, ESI-MS, (ESI) MS/MS analysis, as well as FTIR and 1H-NMR spectroscopy. A conjugated polyrotaxane copolymer with PMeβCD/structural unit ratio of about 1/3 and the number average molecular weight (Mn) value of 30600 was obtained by 1H-NMR spectroscopy and gel permeation chromatography, respectively. The thermal, optical, surface morphology and the adhesion characteristics were investigated and compared to those of the non-rotaxane counterpart poly[2,7-(9,9-dioctylfluorene)-alt-(5,5′-bithiophene) (3).
Thermal Analysis and Theoretical Study of [alpha]-Cyclodextrin Azomethine [2]-Rotaxane Formation by Semi-Empirical Method Pm3
Chemical Physics …, 2011
... OF - CYCLODEXTRIN AZOMETHINE [2]-ROTAXANE FORMATION BY SEMI-EMPIRICAL METHOD PM3 Aurica Farca... more ... OF - CYCLODEXTRIN AZOMETHINE [2]-ROTAXANE FORMATION BY SEMI-EMPIRICAL METHOD PM3 Aurica Farcas a*1 , Adrian Fifere a , Iuliana Stoica a , Flavian Farcas b , Ana-Maria Resmerita aa P. Poni Institute of Macromolecular Chemistry, 41A Gr. Ghica Voda Alley ...
Electro-optical properties of aromatic oligoazomethine/permethylated α-cyclodextrin main-chain polyrotaxanes
Chemical Physics Letters, 2014
ABSTRACT The effect of oligoazomethines (OA) encapsulation into the cavity of permethylated α-cyc... more ABSTRACT The effect of oligoazomethines (OA) encapsulation into the cavity of permethylated α-cyclodextrin on the electro-optical properties was investigated. The polyrotaxane (OA-Rot) formation leads to distinct improvements in the solubility and film forming ability, as well as photophysical and morphological properties, compared with OA unthreaded analogues. The 2D and 3D AFM images of the OA-Rot film showed a smoother and uniform surface. In addition, the HOMO/LUMO energy levels, as well as the energy band gap of OA-Rot are slightly lower than OA counterpart. As expected, doping of the rotaxane structures with iodine showed a smaller enhancement of the electrical conductivity.
Synthesis and characterization of low molecular weight poly(1-butene) macromolecules prepared using metallocene catalysts
Applied Catalysis A: General, 2013
Abstract Poly(1-butene) low molecular weight macromolecules with molecular weights within 1000–20... more Abstract Poly(1-butene) low molecular weight macromolecules with molecular weights within 1000–20,000 g mol −1 and isotacticities around 50–90% were prepared by the polymerization of 1-butene in liquid phase with n-butane as solvent using two metallocene catalysts: rac-dimethyl-silyl-bis-(2-methyl-4,5-benzoindenyl)zirconium dichloride (A) and rac-dimethyl-silyl-bis-(2-methylindenyl)zirconium dichloride (B). Catalyst A showed higher yields and productivities than catalyst B, as well as better isotacticity values, which were ascribed to the presence of an additional aryl substituent in the indenyl moiety which increases its stability and hinders deactivation phenomena by aggregation. Kinetic experiments with catalyst A showed a continuous increase in conversion along the time so no strong deactivation was observed. With catalyst A, an increase in the hydrogen pressure at 75 °C up to 6.0 bar led towards low molecular weight macromolecules with 3000–4000 g mol −1 and a isotacticity of 75–80%. An enhancement in temperature up to 105 °C decreased the yields, molecular weights and isotacticity for both catalysts. Additionally, increasing the hydrogen partial pressure to 1.0 bar at 95 and 105 °C decreased the molecular weight within the 3000–5500 g mol −1 range. XRD patterns of the majority of low molecular weight macromolecules showed the presence of mixed phases, although some low molecular weight macromolecules with pure phase I (twined hexagonal) were obtained. Additionally, the DSC thermograms showed a decrease in the melting temperatures of the crystalline phases of poly(1-butene) low molecular weight macromolecules with regard to the corresponding ones of poly(1-butene) polymers ( M w > 100,000 g mol −1 ), due to their lower molecular weight.
The present manuscript reports an overview of the design and conceptual approaches to the synthes... more The present manuscript reports an overview of the design and conceptual approaches to the synthesis of rotaxaconjugated polymers (R-CP), such as aromatic polyazomethines, alternating or random polyfluorene copolymers encapsulated inside native CD cavities. Their synthesis correlated with an overview of the photophysical properties, surface morphology and electrochemical behaviours, which are advantageous for the generation of active layers in organic electronic devices, are considered in this review.
Molecules
Herein, we report the synthesis of inclusion complexes (ICs) based on 3,4-ethylenedioxythiophene ... more Herein, we report the synthesis of inclusion complexes (ICs) based on 3,4-ethylenedioxythiophene (EDOT) with permethylated β-cyclodextrins (TMe-βCD) and permethylated γ-cyclodextrins (TMe-γCD) host molecules. To prove the synthesis of such ICs, molecular docking simulation, UV-vis titrations in water, 1H-NMR, and H-H ROESY, as well as matrix-assisted laser desorption ionization mass spectroscopy (MALDI TOF MS) and thermogravimetric analysis (TGA) were carried out on each of the EDOT∙TMe-βCD and EDOT∙TMe-γCD samples. The results of computational investigations reveal the occurrence of hydrophobic interactions, which contribute to the insertion of the EDOT guest inside the macrocyclic cavities and a better binding of the neutral EDOT to TMe-βCD. The H-H ROESY spectra show correlation peaks between H-3 and H-5 of hosts and the protons of the guest EDOT, suggesting that the EDOT molecule is included inside the cavities. The MALDI TOF MS analysis of the EDOT∙TMe-βCD solutions clearly rev...