Bartosz Boharewicz

In this paper, we present a novel approach developed in order to increase the reliability and accuracy of AFM investigation of morphological changes in a nanocomposite due to exposure to the media causing its degradation. By precise sample positioning and repetitive determination of the roughness changes at specific spots, we were able to create space-related degradation profiles. As the multi-step experiment based on exposure/scanning cycle was performed, we were able to observe a unique response of investigated samples revealing spatial inhomogeneity of the material. In order to present the measurement methodology, we used polystyrene samples containing various quantities of PC₆₁BM nanofiller (0 %, 5 %, 10 % and 20 % of mass proportion), which was exposed to 370 nm UV radiation. Obtained data can be recognized as specific fingerprints of investigated materials. The solution based on creation and analysis of degradation profiles can be particularly useful for diagnostics of nanomaterials and nanocomposites to test their resistance to various conditions.

The wet ultrasonochemical method was used to obtained TiO₂/n-Ag nanoparticles for polymer solar cells.

We propose, for the first time, aromatic polyazomethines applied in polymer electrolyte membrane fuel cells (PEMFC) as tetrafluoroethylene-perfluoro-3,6-dioxa-4-methyl-7-octene-sulfonic acid copolymer (PFSA) membrane modifiers. Two types of polyazomethines were selected to impregnate pristine PFSA membranes; one with bibenzimidazole groups (25Bo-BABPI) and the second with thiophene rings (2252Th-DMB). In addition, these composite membranes were doped using imidazole (Im) to increase the proton conductivity. The success of the impregnation process of all modified membranes has been confirmed based on FTIR spectroscopy. From the water sorption analysis performed, the obtained PFSA composite membranes were found to be thermally stable (TGA, DTG results) and revealed lower dependency on water, which served as an advantage. The typical membranes used were activated in boiling deionized water, then in 3.75% H₂O₂, and finally in boiling 0.2 M H₂SO₄. Moreover, both polyazomethines were oxidized with FeCl₃ to check their chemical oxidation abilities. Single PEMFCs assembled using polyazomethine composite membranes were characterized by improved performance, increase in the maximum power density by two folds, higher proton conductivity and larger electrochemical surface area of catalyst in comparison to reference samples. The maximum power density of 231 mW cm⁻² at the current density of 637 mA cm⁻² was detected for PFSA–25Bo-BABPI membrane. In accordance with the experiments carried out, polyazomethines have positive influence on PEMFCs' overall electrochemical properties. All membranes were tested by atomic force microscopy (AFM) and scanning electron microscopy (SEM) with EDX to analyze their morphology.

New photosensitive liquid crystalline compounds with a specific molecular structure have been designed in order to use them as functional dopants for organic photovoltaic devices.