Fluorofunctional silanes, polysiloxanes and silsesquioxanes were used for the modification of glass surfaces and their influence on hydrophobic properties were determined. To increase hydrophobicity of the surface, the modification was performed in two stages: (i) by a pretreatment using a silica sol (a rise in the surface roughness), and (ii) modification with the above silicon compounds. The hydrophobicity was determined by measuring the contact angle by drop profile tensiometry. The fluorocarbofunctional organosilicon derivatives examined were found to be good precursors for the synthesis of highly hydrophobic materials and coatings. In some cases the contact angles measured after surface modification exceeded 150°, i.e. they fell in the range characteristic of superhydrophobic surfaces.
Interest in graphene oxide nature and potential applications (especially nanocarriers) has resulted in numerous studies, but the results do not lead to clear conclusions. In this paper, graphene oxide is obtained by multiple synthesis methods and generally characterized. The mechanism of GO interaction with the organism is hard to summarize due to its high chemical activity and variability during the synthesis process and in biological buffers’ environments. When assessing the biocompatibility of GO, it is necessary to take into account many factors derived from nanoparticles (structure, morphology, chemical composition) and the organism (species, defense mechanisms, adaptation). This research aims to determine and compare the in vivo toxicity potential of GO samples from various manufacturers. Each GO sample is analyzed in two concentrations and applied with food. The physiological reactions of an easy model Acheta domesticus (cell viability, apoptosis, oxidative defense, DNA damage) during ten-day lasting exposure were observed. This study emphasizes the variability of the GO nature and complements the biocompatibility aspect, especially in the context of various GO-based experimental models. Changes in the cell biomarkers are discussed in light of detailed physicochemical analysis.
This work presents the preparation and characterization of pristine and transition metal doped partially reduced graphene oxide aerogels. The step-by-step preparation of aerogels from graphene oxide with an assistance of VCl3, CrCl3, FeCl2·4H2O, CoCl2, NiCl2 and CuCl2 chlorides as reducing agents is shown and explained. The influence of reducing agents on the structural and magnetic properties of prepared aerogels is investigated. The use of electron paramagnetic resonance in purification during synthesis of GO and characterization afterwards is shown. It was found that VCl3 was the strongest reducing agent leading to the formation of the most dense reduced graphene oxide aerogel, whereas vanadium is visible in EPR spectrum in form of V4+ complex as a VO2+ groups.