Πλοήγηση ανά Συγγραφέας "Anagnostou, Aikaterini"

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    An extensive case study on the dispersibility parameters of HI-Assisted reduced graphene oxide and its graphene oxide precursor.
    (ΕΛ.ΜΕ.ΠΑ., Σχολή Μηχανικών (ΣΜΗΧ), ΔΠΜΣ Νανοτεχνολογία για Ενεργειακές Εφαρμογές, 2020-09-11) Anagnostou, Aikaterini; Αναγνώστου, Αικατερίνη
    In this work, the optimal dispersibility conditions of chemically prepared graphene oxide (GO) and reduced graphene oxide (RGO) has been extensively investigated in 25 different organic and inorganic solvents. Graphite oxide was prepared chemically from graphite powder via modified Hummers’ method. It was then dispersed with an initial concentration of 0.5 mg/ml in 25 different solvents using ultrasonic probe to create GO suspensions. Likewise, reduced graphite oxide, which was chemically prepared from graphite oxide using hydroiodic acid and acetic acid and dispersed in the same 25 solvents. All dispersions were centrifugated and left for 2 weeks before measurements and characterisation in order to insure stability of the suspended materials. The difference in the dispersion behaviour of these two materials was investigated by determining the final concentration of GO and RGO in each solvent through Beer-Lamberts law after determining the maximum absorbance via UV-Vis spectroscopy. The use of an ultrasonic probe is an improvement on previous investigations of the dispersion behaviour of GO and RGO, which achieved liquid exfoliation using an ultrasonic bath. Concentrations of up to 189 μg/ml for GO and 87 μg/ml for RGO were achieved in de-ionised water and o-dichlorobenzene respectively. The Hansen Solubility Parameters (HSP) of GO and RGO were calculated in hopes of providing insight into their affinity for these solvents for future work. An attempt to measure the zeta-potential of each dispersion in order to evaluate their stability was made. These characterisations, however, were not feasible due to intense agglomeration of GO and/or RGO occurring in some dispersions during the measurement of both GO and RGO. Finally, the average flake size distribution and polydispersity indices of GO and RGO in all solvents were estimated using dynamic light scattering (DLS), as a quality control of the effect of a solvent’s nature on the dispersion behavior of the materials.