The contact electrification of polymer interfaces provides an energy harvesting function to triboelectric (nano)generators (TEG). The electron transfer between contacted-separated surfaces has been considered as the main electrification mechanism for polymers in TEG. The electron transfer mechanism widely proposed in literature requires a contact between chemically different polymer materials, as well as subsequent increase of the specific contact area, which is commonly accomplished via nanostructuring. Herein, we showed that contact electrification could be controlled by intramolecular forces in the polymer bulk and adhesive forces at the contact interface, and the chemical contact between different polymers was not needed for contact electrification. The results also confirm the breaking of the covalent bond as a mechanism of the contact electrification of polymer insulators.

Triboelectric nanogenerators based on ferroelectric materials exhibit boosted performance due to magnified induction by piezoelectric charges.

By using a solvent-based method composites of ethylenevinyl acetate copolymer and carbon black (EVA–CB) were synthesized for sensing BTEX (benzene, toluene, ethylbenzene and xylene) vapours. The composites were characterized using atomic force microscopy (AFM) in an electroconductive mode. Gas sensing results show that EVA-CB can reproducibly detect BTEX and that the response increases linearly with vapour concentration. Compared to gas-sensing measurements of gasoline vapours, the responses with toluene and ethylbenzene are different and can be explained by varying side chains of the benzene ring.

The amount and alignment of hydroxyl ions influence the bioactivity of hydroxyapatite. Hydroxyl ions in hydroxyapatite are the most mobile and upon heating are the first to leave the lattice to form oxyhydroxyapatite. This work describes a method for producing hydroxyapatite with different amounts of hydroxyl ions, and reports on the changes in Fourier transform infrared absorption at increasing level of dehydroxylation. Detailed analysis of spectra in the 500 – 700 cm^-1 range showed a peak shift for the hydroxyl ion absorption line at 632 cm^-1 to 637 cm^-1 and an increase in the wavenumber for the phosphate line at 575 cm^-1.

Carbon black-ethylene-octene copolymer (EOC-CB) composite electro-thermal properties were investigated for using the composite as self-regulating heating material. The materials electrical resistance change with temperature change was investigated. Additionally, while a voltage of 30 V was applied, the sample temperature and electrical current strength was measured. The samples with 15 to 20 phr CB showed positive temperature coefficient of resistivity and could be used as self-regulating heating materials. For different concentrations of CB the achieved equilibrium temperatures were between 30°C to 60°C (with 30 V) and could be used to comfortably warm the human body.