Phenoxazine Based Units- Synthesis, Photophysics and Electrochemistry

A few new phenoxazine-based conjugated monomers were synthesized, characterized, and successfully used as semiconducting materials. The phenoxazine-based oligomers have low ionization potentials or high-lying HOMO levels (~4.7 eV), which were estimated from cyclic voltammetry. Conjugated oligomers offer good film—forming, mechanical and optical properties connected with their wide application. These results demonstrate that phenoxazine-based conjugated mers are a promising type of semiconducting and luminescent structures able to be used as thin films in organic electronics

Perinone—New Life of an Old Molecule

A review of publications on the synthesis and properties of a family of compounds called perinones was carried out. The basic molecule has been known for several decades mainly as a photostable pigment, and in recent years it has become increasingly used in organic electronics. This paper describes the methods of synthesis of low molecular weight compounds and polymers based on that molecule; the basic spectroscopic, photochemical, electrochemical and electronic properties important for the construction of organic electronics and optoelectronics devices are also discussed

E-mail, E-paper, E-skin ?

Przeszczepianie skóry jest zagadnieniem znanym już na dwa i pół tysiąca lat przed naszą erą, kiedy to przeprowadzano pierwsze eksperymenty z jej zakresu. Najnowszymi owocami tej dziedziny jest tzw. e-skóra - membrana wrażliwa na nacisk. Ostatnimi czasy ogłoszono powstanie dwóch jej modeli, autorstwa niezależnych zespołów naukowców. Artykuł opisuje ich budowę oraz zasadę funkcjonowania, a także opracowany wcześniej czujnik ciśnienia, który mógł stanowić inspirację dla twórców e-skóry.The first experiments that gave birth to the discipline of skin grafting date back to two and a half millennia B.C. The most recent fruit of this branch of science is e-skin - a pressure-sensitive membrane. Lately, the completion of two models of such a membrane by independent research teams has been announced. The article describes the construction and the operating principles of those models, as well as a pressure sensor that has been developed before them and might have served as a source of inspiration for the creators of the e-skin

An Insight into Ionic Conductivity of Polyaniline Thin Films

The work addresses an issue of the conductivity phenomenon in conductive polymer thin films. Polyaniline was chosen as a broadly used and thoroughly investigated conductive polymer in order to test and show capabilities of the developed original approach based on impedance spectra analysis. A number of films of different thickness were deposited onto a Pt electrode surface and consequently investigated in aqueous solution containing perchloric acid as an electrolyte. The processes that occur in polyaniline film were studied by cyclic voltammetry, electrochemical quartz crystal microgravimetry (EQCM) and electrochemical impedance spectroscopy (EIS). The role of incorporated ions as charge carriers was investigated with respect to the control of the conductivity properties of the film. Along with detailed polyaniline behavior study, the work makes up a fundamental scientific impact on theoretical electrochemistry and electroanalytical techniques

Isothermal plastic forming of high melting temperature alloys

This paper deals with the problem of an unconventional plastic forming process—deformation of high melting temperature alloys under isothermal conditions. The test were performed for alloyed steel containing 0.5% C. The upsetting process at various temperatures and strain rates was used to determine the optimum parameters of deformation. In order to obtain fine grains prior to deformation and create the superplasticity effect, the samples were subjected to thermomechanical processing. The main experiment included axisymmetrical closed-die forging. Very good filling of the grove and low loads were observed in all tests. Despite the relatively long time of deformation at high temperatures, the material maintained a fine microstructure

Feasibility of metal forming in semi-liquid state

The work described in this paper is connected with Author's earlier research on the formability of alloys in semi-liquid (partly liquid) state, i.e. at the temperatures exceeding their solidus points. Two aluminium based alloys of a relatively large crystallization temperature range have been used as the testing materials. The investigation focused on the effect of the liquid fraction (volume percentage of liquid component in the alloy, pre-heated to the temperature above its solidus point) on the parameters of the plastic deformation. The process of upsetting of the cylindrical specimens is investigated. The prime objective of the work is to determine the factors which affect the softening of various alloys subjected to deformation in semi-liquid state. An attempt of the generalization of the problem is done. Thermal-mechanical finite element model developed for the compression process and adapted to the semi-liquid conditions is used for the calculation of the deformation parameters

Isothermal plastic forming of high-carbon steel

The work deals with the problem of an unconventional plastic forming process—deformation of high melting temperature alloys in isothermal conditions. The tests were performed for alloyed steel containing 0.5%C. Upsetting the process at various temperatures and strain rates was used to determine the optimum parameters of deformation. In order to obtain fine grains prior to deformation and to create the superplasticity effect, the samples were subjected to thermomechanical processing. The main experiment included axisymmetrical closed die forging. Very good filling of the groove and low loads were observed in all tests. In spite of relatively long time of deformation at high temperatures, the material maintained fine microstructure

Spectroelectrochemical techniques as modern tools for investigating charge transfer processes in conjugated polymers

Techniki elektrochemiczne, pozwalające monitorować procesy przeniesienia ładunku, są szeroko wykorzystywane do badania związków organicznych z grupy polimerów skoniugowanych. Materiały te znajdują zastosowanie w optoelektronice i są podstawą opracowania takich urządzeń elektroniki organicznej jak nowoczesne panele fotowoltaiczne, diody elektroluminescencyjne, tranzystory polowe, okna elektrochromowe i sensory chemiczne. Właściwości tych materiałów oraz ich zmiany podczas przebiegu procesów przeniesienia ładunku są jednym z głównych tematów badań prowadzonych z wykorzystaniem technik spektroelektrochemicznych w Katedrze Fizykochemii i Technologii Polimerów Politechniki Śląskiej. Sztandarową techniką należącą do tej grupy jest spektroelektrochemia EPR-UV-Vis-NIR, pozwalająca jednocześnie śledzić zmiany właściwości optycznych układów skoniugowanych i powstawanie oraz zanik nośników ładunku. Powiązanie ze sobą tych informacji pozwala na przypisanie, obserwowanym w warstwie polimerowej, rodzajom nośników ładunku przejść elektronowych i kompleksowa dyskusja zachodzących procesów domieszkowania/ oddomieszkowania.Electrochemical analysis techniques, allowing charge transfer processes to be followed, are frequently utilised in the study of organic compounds belonging to the group of conjugated polymers. These materials are widely used in optoelectronics and are the basis for the development of organic electronics devices, such as modern photovoltaic panels, light-emitting diodes, field effect transistors, electrochromic windows and chemical sensors. The physicochemical properties of these materials and their changes in the course of charge transfer processes are one of the main topics of research, conducted with the use of spectroelectrochemical techniques, in the Department of Physical Chemistry and Technology of Polymers at the Silesian University of Technology. The leading technique belonging to this group is EPRUV- Vis-NIR spectroelectrochemistry, allowing the changes in optical properties of conjugated systems to be followed simultaneously with the generation and decay of charge carriers. Joint consideration of this information allows electronic transitions, observed in the polymer layer, to be assigned to types of charge carriers types and the processes of doping / dedoping to be comprehensively discussed