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Unoriented and oriented membranes based on dendronized polymers and copolymers obtained by chemical modification of poly[2-(aziridin-1-yl) ethanol] (PAZE) with the dendron 3,4,5-tris[4-(n-dodecan-1-yloxy)benzyloxy]benzoate were considered. DSC, XRD, CP-MAS NMR and DETA, contribute to characterize the tendency to crystallize, the molecular mobility of the benzyloxy substituent, the dendritic liquid crystalline group and the clearing transition. The orientation of the mesogenic chain somewhat hindered this molecular motion, especially in the full substituted PAZE. The fragility, free volume and thermal expansion coefficients of these membranes near the glass transition are related to the orientation and the addition of the dendritic groups. PAZE-based membranes combine both order and mobility on a supramolecular and macroscopic level, controlled by the dendritic group and the thermal orientation, and open the possibility of preparing membranes with proper channel mobility that promotes selective ionic transport. [ABSTRACT FROM AUTHOR]

Poly(3,4-ethylenedioxythiophene:poly(styrenesulfonate) (PEDOT:PSS) water and toluene solutions were investigated in detail, taking into consideration their stability, wettability, transparency, and electrochemical properties, along with change polarity caused by dopant. As dopant, methanol, ethanol, and isopropanol were used with different dipole moments (1.70, 1.69, and 1.66 D) and dielectric constants (33.0, 24.5, and 18.0). Three techniques, i.e., spin coating, doctor blade coating, and spray coating, were employed to created PEDOT:PSS layers on glass, glass/indium tin oxide (ITO), and glass/fluorine-doped tin oxide (FTO) substrates with optimized technical parameters for each used equipment. All used PEDOT:PSS water and toluene solutions demonstrated good wetting properties with angles below 30° for all used surfaces. Values of the energy bandgap (Eg) of PEDOT:PSS investigated by cyclic voltammetry (CV) in solution showed increase energy Eg along with addition of alcohol to the mixture, and they were found in the range of 1.20 eV to 2.85 eV. The opposite tendency was found for the Eg value of the PEDOT:PSS layer created from water solution. The storage effect on PEDOT:PSS layers detected by CV affected only the lowest unoccupied molecular orbital (LUMO) level, thereby causing changes in the energy bandgap. Finally, simple devices were constructed and investigated by infrared (IR) thermographic camera to investigate the surface defects on the created PEDOT:PSS layers. Our study showed that a more stable PEDOT:PSS layer without pin-holes and defects can be obtained from water and toluene solutions with isopropanol via the spin coating technique with an optimal speed of 3000 rpm and time of 90 s. [ABSTRACT FROM AUTHOR]

We report here the preparation and thermal, electrical and mechanical characterization of binary and ternary films based on l,d-poly(lactic acid) (l,d-PLA) and 4′-pentyl-4-biphenylcarbonitrile (5CB) and Single Walled Carbon Nanotubes (SWCN) with various weight ratio. The transitions for all investigated hybrid compositions detected by differential scanning calorimetry method were shifted to lower temperatures with increasing the concentration of 5CB in the mixture with polymer. Frequency domain dielectric spectroscopy method and thermal imaging together with polarized optical microscope were used to study electric and structural properties of created hybrid compositions. The best electrical conductivity was observed for hybrid composite l,d-PLA:5CB:SWCN with ratio 10:1:0.5 w/w/w - resistance of 41.0 Ω and thermal response up to 160 °C without causing any damages. Films in crystal form are much more inflexible than in amorphous and can be explain by the cold crystallization occurs at heating while the materials changed their physical state. The value of ε′ increases with increasing the 5CB admixture. Moreover, the addition of 5CB to l,d-PLA resulted in increased flexibility of polymeric base films. The best material flexibility and short-term strength were obtained for l,d-PLA sample with 9% 5CB content. [ABSTRACT FROM AUTHOR]

We report on the application of l,d-poly(lactic acid) (l,d-PLA) with dispersed Single-Walled Carbon Nanotubes (SWCN) as a flexible translucent electrode for organic devices. We used commercially available nanotubes in various weight ratios from 0 to 8% dispersed in chloroform polymeric solution by ultrasonication and were drop cast. The created hybrid materials were investigated by differential scanning calorimetry to determine the influence of SWCN content on the thermal behavior, while polarizing optical microscope was used to find the effect of mechanical deformations on the textures. Drop-cast films were studied by optical transmittance, conductivity, dielectric properties and by thermal imaging under applied potential. Thermal imaging provided evidence of visible voltage-activated conduction. Simple mechanical deformation such as bending with stretching at edge to ca. 90 and elongation test were performed. Moreover, interactions between l,d-poly(lactic acid) and SWCN were investigated by FT-IR and NMR spectroscopy. Finally, we can conclude that the thermographic examination of created films permits fast, simple and inexpensive localization of defects on the surface of l,d-PLA:SWCN film, together with the electrical properties of the films. [ABSTRACT FROM AUTHOR]

Low-modified liquid-crystalline polyether (CP36), as a model compound, was synthesised with the purpose of preparing a membrane with columnar ionic channels. A free-standing cation permselective biomimetic membrane was successfully prepared and found to have channels made of polymeric columns homeotropically oriented, which was confirmed in X-ray diffraction (XRD) analysis. A first insight into a real-time interaction between two selected cations: H+ and Na+, and polyether during transport through the polymeric membrane was demonstrated using joined chronoamperometry and Raman spectroscopy techniques. Raman studies unveiled the possibility for smaller protons to bypass the usual ionic pathway via polyetheric chain and use outer part of ionic channel for conduction thanks to ester bonds. [ABSTRACT FROM AUTHOR]