Bozena Jarzabek

New Conjugated Azomethines Containing Triphenylamine Core —Characterization and Properties

A novel polyazomethines bearing triphenylamine core and a proper model compound were synthesized and their spectroscopic (FTIR, 1 H NMR) and optical (UV-vis, photoluminescence) properties and also a molecular dynamic calculations were investigated. The polymers which were soluble in organic solvents (chloroform, dimethylacetamide, m-cresol) and formed transparent foils, emitted blue light and their photoluminescence band and intensity were solvent dependent. Additionally, the effects of blending the new polyazomethines with other polymers—PMMA, polyvinylophenol on UV-vis spectra were examined. Non-covalent ionic-type interactions between azomethines and methanesulfonic acid (MSA), m-cresol (MC) and p-chlorophenol (pClp) were also investigated. The structure formation of azomethines complexes are discussed on the basis of 1H NMR and FTIR. Photoluminescence and absorption properties of the azomethines compounds after doping with MSA, MC and pClp were tested.

Characterization, optical and thermal properties of new azomethines based on heptadecafluoroundecyloxy benzaldehyde

New thermotropic liquid crystals containing a long alkoxysemiperfluorinated chain (-O-(CH2)3-(CF2)7-CF3), one linking unit in mesogenic cores (HC=N-) and different functional end-groups such as 4-hexadecyl-, 4-n-hexadecyloxy- chain, or biphenyl-4-carbonitrile, 4-diazenyl-N,N-dimethylbenzene or pyren were synthesized via a one-step route. The methods of nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), ultraviolet–visual (UV-vis) and photoluminescence (PL) spectroscopy as well as differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) were used. The absorption (UV-vis) and PL features of all compounds are documented. The amine had an effect on the mesomorphic properties of the azomethines. An enantiotropic smectic phase was observed for all of the systems studied. As a result of DSC and POM investigations, it is shown that liquid crystalline properties of the azomethines exhibit a strong dependence of the end-groups. The mesomorphic behaviour of the compounds was investigated also by FTIR(T) and UV-vis(T) spectroscopy. Current–voltage measurements were performed on an ITO/compound/Alq3/Al device.

Mesomorphic Behavior of Symmetrical and Unsymmetrical Azomethines with Two Imine Groups

Seven symmetrical azomethines with two imine groups (HC=N) were synthesized by condensation of the benzene-1,4-dicarboxaldehyde with five amines (first group: A1-A5) and of the 2,5-thiophenedicarboxaldehyde with two amines (second group: AT1-AT2). Additionally, two unsymmetrical azomethines were obtained by a two step condensation of benzene-1,4-dicarboxaldehyde with pyren-1-amine (1st step) (abbreviated hereinafter as AP1) and then AP1 was reacted with 4-dodecylaniline or 4-hexadecylaniline (2nd step) (third group: AP1A-AP1B). Liquid crystalline properties of the azomethines were studied by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and UV-vis spectroscopy in the function of temperature [UV-vis(T)]. The Wide-Angle X-ray Diffraction (WAXD) technique was used to probe the structural properties of the azomethines. Mesomorphic behavior was observed for symmetrical and unsymmetrical azomethines, obtained from the benzene-1,4-dicarboxaldehyde and symmetrical ones prepared from 2,5-thiophenedicarboxaldehyde and different amines having aliphatic chains. Based on the POM and DSC measurements the following mesophases were detected: nematic, smectic A, smectic C, smectic F (I), smectic G (J).

Star-shaped azomethines based on tris(2-aminoethyl)amine. Characterization, thermal and optical study.

The synthesis and detailed (physico)-chemical ((1)H/(13)C NMR, FTIR, UV-vis and elemental analysis) characterizations of new star-shaped compounds based on tris(2-aminoethyl)amine, including in their structure an azomethine function (HCN-) and alkoxysemiperfluorinated (-O-(CH(2))(3)-(CF(2))(7)-CF(3)), octadecyloxy aliphatic (-O-(CH(2))(17)-CH(3)) chain or two phenyl rings (-Ph-Ph-) as a terminal group, were reported. The mesomorphic behavior was investigated by means of differential scanning calorimetry (DSC), polarized optical microscopy (POM) and additionally by FTIR(T) and UV-vis(T) spectroscopy. Wide-angle X-ray diffraction (WAXD) technique was used to probe the structural properties of the azomethines. Moreover, the azomethine A1 was electro-spun to prepare fibers with poly(methyl methacrylate) (PMMA) and investigated by DSC and POM. Additionally, a film of the A1 with PMMA was cast from chloroform and the thermal properties of the film were compared with the thermal properties of the fiber and powder. It was showed that terminal groups dramatically influence the thermal and optical properties of the star-shaped azomethines.

Local delivery system of doxycycline hyclate based on ϵ-caprolactone copolymers for periodontitis treatment

The aim of the study was to evaluate kinetics of doxycycline hyclate release from polymeric bioresorbable implants and to examine suitability of this system for local treatment of periodontitis. Selected trimethylene carbonate/ϵ-caprolactone (TMC/CL) and glycolide/caprolactone (GL/CL) copolymers were synthesized and used as carriers in the form of small elastic rings with 5 wt% and 10 wt% doxycycline hyclate content, or in the form of flakes obtained through electro-spinning technique. The release of the drug under in vitro conditions has been tested. The study has shown that equimolar TMC/CL copolymer loaded with 10 wt% of doxycycline hyclate appears to be the most suitable copolymer for assumed system. The drug release proceeds mainly by diffusion of medium into the polymeric matrix and then the drug is washed out. Daily validation of doxycycline doses released by the system should ensure accurate course of the therapy.

The synthesis and thermal, optical and electrical properties of novel aromatic–aliphatic five- and six-membered thermotropic polyimides

Polymers have been prepared by the polycondensation of 4,4′-(butane-1,4-diylbis(oxy)) bis(butane-4,1-diyl) bis(4-aminobenzoate) and 5,10,15,20,25,30,35,40,45,50,55,60-dodecaoxatetrahexacontane-1,64-diyl bis(4-aminobenzoate) (PBBA 1200) with three dianhydrides based on naphthalene, perylene and phthalic moieties, respectively. This has resulted in five novel aliphatic–aromatic polyimides. The polyimides differed in aliphatic chain length and whether the imide ring was five- or six-membered. The chemical structure of the polyimides has been confirmed by 1H NMR and FTIR spectroscopy and by elemental analysis. The optical and electrical properties of the polyimides have been studied using current–voltage measurements, and the effect of the polyimide structure on thermal and mesomorphic behaviour investigated by differential scanning calorimetry and polarising optical microscopy. Wide-angle X-ray diffraction at different temperatures was employed to confirm the structural properties of the polyimides. All the novel polyimides, with the sole exception of that obtained from PBBA1200 and 3,4,9,10-perylenetetracarboxylic dianhydride, showed liquid crystalline properties. As far as we are aware, this is the first time that six-membered polyimides exhibiting liquid crystalline properties have been reported.

Supramolecular Modification of Optical Properties of Some New Polyazomethines

Novel polyazomethines containing triphenylamine structure in the main chain have been prepared on a way of polycondensation of 4,4′-diformyltriphenylamine with aromatic diamines in HMPT solution with the goal to study interactions between polymer chain (Ps) and dopant (methanesulfonic acid: MSA, m-cresol: MC and p-chlorophenol: pClp) by FTIR, UV-vis and PL measurements. The electronic absorption spectra and photoluminescence spectra of polyazomethines detected in various solutions were dependent on the diamines structures and could be tuned by supramolecular modification via protonation or H-bond formation of imine group with the dopant. Preliminary results suggest that the polyazomethines can be blue light emitting materials.

Optical properties of amorphous cadmium arsenide

Abstract Absorption coefficient α(E), refractive index n(λ) and reflectivity A have been calculated and compared with those for crystalline films. The effect of the film deposition rate on the position of absorption edge was found. With the increasing deposition rate and thus with the increasing film nonstoichiometry the fundamental absorption edge has been shifted to higher energies from about 0.35 eV to 0.55 eV. The results are discussed on the basis of the band model proposed previously for explaining the transport phenomena for these films.

Thermal stability and optical properties of aromatic polyimides containing side-substituted azobenzene groups

Aromatic azopolyimides based on 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride and aromatic diamines containing substituted azobenzene group have been studied regarding their thermal and photooptical properties. The thermal analysis showed that the decomposition of these polymers takes place in two or three stages. The optical properties of the investigated polymers have been analyzed by transmission and reflectivity measurements within the spectral range of 200–2500 nm. Temperature dependence of absorption coefficient has been found on the basis of “in situ” transmission measurements, during annealing of thin films up to 300°C. It turned out that this process did not change the conjugation of polymer chain but caused a slightly more, irreversible structural disorder.

Novel Poly(L-lactide-co-ε-caprolactone) Matrices Obtained with the Use of Zr[Acac]4 as Nontoxic Initiator for Long-Term Release of Immunosuppressive Drugs

Slowly degradable copolymers of L-lactide and ε-caprolactone can provide long-term delivery and may be interesting as alternative release systems of cyclosporine A (CyA) and rapamycin (sirolimus), in which available dosage forms cause a lot of side effects. The aim of this study was to obtain slowly degradable matrices containing immunosuppressive drug from PLACL initiated by nontoxic Zr[Acac]4. Three kinds of poly(L-lactide-co-ε-caprolactone) (PLACL) matrices with different copolymer chain microstructure were used to compare the release process of cyclosporine A and rapamycine. The influence of copolymer chain microstructure on drug release rate and profile was also analyzed. The determined parameters could be used to tailor drug release by synthesis of demanded polymeric drug carrier. The studied copolymers were characterized at the beginning and during the degradation process of the polymeric matrices by NMR spectroscopy, GPC (gel permeation chromatography), and DSC (differential scanning calorimetry). Different drug release profiles have been observed from each kind of copolymer. The correlation between drug release process and changes of copolymer microstructure during degradation process was noticed. It was determined that different copolymer composition (e.g., lower amount of caprolactone units) does not have to influence the drug release, but even small changes in copolymer randomness affect this process.