Monika Zięba

We report for the first time the chromatographic study of n-alcohols (from methanol to butanol) adsorption on single walled carbon nanohorn (SWCNH). Using measured temperature dependence of adsorption isotherms (373–433 K) the isosteric adsorption enthalpy is calculated and compared with the data reported for a graphite surface. It is concluded that a graphite surface is more homogeneous, and the enthalpy of adsorption on SWCNHs at zero coverage correlates well with molecular diameter and polarizability, suggesting leading role of dispersive interactions, i.e., no heteroatoms presence in the walls of SWCNH structures. Next using modern DFT approach we calculate the energy of n-alcohols interactions with a graphene sheet and with a single nanocone finally proposing a more realistic—double nanocone model. Obtained results suggest alcohols entrapping between SWCNH with OH groups located toward nanocones ends, leading to the conclusions about very promising future applications of SWCNHs in catalytic reactions with participation of n-alcohols.

The results of in vitro studies of single-walled carbon nanohorn (SWCNH) oxidized materials’ cytotoxicity obtained by the cell membrane integrity (Neutral Red Uptake (NRU)) and metabolic activity (by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)) on A549 and human dermal fibroblasts (HDF) cell lines are presented. We also present hemocompatibility studies on human and porcine blood, and an erythrocyte concentrate to prove that the obtained samples will not interfere with blood components. Characterization of the materials is supplemented by ζ-potential measurements, Transmission Electron Microscope (TEM) imaging, and thermogravimetric studies (TG). The presented results show the correlation between the specific surface area of materials and the platelet aggregation, when the I_D/I_G ratio determined from Raman spectra correlates with hemoglobin release from the erythrocytes (in whole blood testing). A plausible mechanism explaining the observed correlations is given. The cytotoxicity and hemocompatibility studies prove that the studied materials are acceptable for use in biomedical applications, especially a sample SWCNH-ox-1.5 with the best application potential.

Spherical carbon nanomaterial coatings on the purified carbon fibres were obtained and characterized. The use of exactly the same conditions of electrophoretic deposition process made it possible to compare the impact of the initial carbon nanomaterial properties on the behaviour of various prepared surfaces. Obtained samples were characterized by scanning electron microscopy, atomic force microscopy, flat surface ζ‐potential and water contact angle measurements. Additionally, cytotoxic tests were carried out to compare biocompatibility of coated carbon fibres. Presented results show the impact of the initial materials properties on the characteristics of the deposited coatings.

It is well known that carbon nanotube (CNT) oxidation (usually with concentrated HNO₃) is a major step before the electrophoretic deposition (EPD). However, the recent discovery of the “onion effect” proves that multiwalled carbon nanotubes are not only oxidized, but a simultaneous unsheathing process occurs. We present the first report concerning the influence of unsheathing on the properties of the thus-formed CNT surface layer. In our study we examine how the process of gradual oxidation/unsheathing of a series of multiwalled carbon nanotubes (MWCNTs) influences the morphology of the surface formed via EPD. Taking a series of well-characterized and gradually oxidized/unsheathing Nanocyl™ MWCNTs and performing EPD on a carbon fiber surface, we analyzed the morphology and wettability of the CNT surfaces. Our results show that the water contact angle could be gradually changed in a wide range (125–163°) and the major property determining its value was the diameter of aggregates formed before the deposition process in the solvent. Based on the obtained results we determined the parameters having a crucial influence on the morphology of created layers. Our results shed new light on the deposition mechanism and enable the preparation of surfaces with steerable roughness and wettability.

The anodic oxidation of Ti6Al4V substrate surfaces with the use of cyclically changing potential enabled the production of novel titania nanocoatings. Morphologically different coatings were prepared in the ethylene glycol-based electrolyte with diluted HF and various amounts of water. The structure of the produced surface materials was characterized by X-ray diffraction, Raman spectroscopy, and diffuse reflectance infrared Fourier transform spectroscopy. Their morphology was visualized by scanning electron microscopy. The photocatalytic efficiency of produced materials was studied by the observation of methylene blue degradation under UV irradiation. Their biointegration properties were established on the basis of immunological assays, which checked murine fibroblasts adhesion and proliferation on novel coatings. The obtained results pointed out to both high biocompatibility, as well as the photoactivity of one of the obtained nanocoatings, allowing trusting in the applicative nature of this material.