Chemical precipitation is one of the most commonly used methods for formation of magnetic iron oxide particles, especially when one wishes to obtain stable dispersions of these particles - ferrofluids. Precipitation of magnetic iron oxide from solutions of iron salts has proven itself to be a useful and practical method, since in most cases, high temperatures are not required and the entire synthesis procedure can be carried out in a liquid media, from the formation to processing of particles to subsequent post-treatments, therefore eliminating the possibility of agglomeration of dry particulate powder. We report here on the synthesis of magnetic iron oxide particles at different conditions, with a view on subsequent application of the formed ferrofluid in coating of solid polymer surfaces. Therefore, we have mainly concerned ourselves with the study of the colloidal properties of magnetic particles, since these are the characteristics that will govern the particles’ adsorption/deposition on the solid surface. We have investigated the influence of the synthesis procedure on the resultant particles’ size in aqueous dispersions and their surface potential, as well as changes in size at different pH values.
COBISS.SI-ID: 15381782
Cellulose fibrous substrates are increasingly establishing themselves as a versatile base material for production of various nanocomposites since, beside them being readily available and biodegradable/bio-compatible, they also posses a number of advantageous properties, e.g. good mechanical properties, hydrophillicity,… As such they present themselves as an attractive material for application of nano particles and thus formation of new hybrid organic/inorganic products. But it is essential for cellulose to swell to at least a limited extent in order to enable functionalization treatments; non-swollen cellulose substrate would only allow formation of new functionalities (either adsorption of various coatings, in situ growth of particles) only on the available outer surface of a solid material. Aim of our research was to study the effect of different concentrations of sodium hydroxide on the extent of swelling they cause and the changes in properties of fibers these treatments bring about. Wide-angle X-ray analysis was used to investigate the changes in structure of fibers upon swelling, while their electrokinetical properties, namely zeta potential, provided us with information on their liquid/solid interface properties and wetting.These results were correlated and have shown that swelling pretreatments for cellulose fibers modifies their structural properties, which then later on affect their hydrophillicity and ability to uptake various reaction mixtures for in situ formation of particles or present a higher surface area for adsorption of particulate matter or polymer solutions.
COBISS.SI-ID: 15382294