Browsing by Author "Sepulveda Suazo, Antonia Paz"

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    Puesta a punto del proceso de reducción del óxido de grafeno: influencia de las condiciones de operación.
    (Universidad de Concepción, 2023) Sepulveda Suazo, Antonia Paz; Fernández Elgueta, Katherina
    Composite materials based on graphene offer excellent properties due to their high electrical and thermal conductivity, making it attractive in applications ranging from electronics to energy and medicine. Due to their low cost and high production, graphene oxide (GO) and reduced graphene oxide (rGO) are ideal candidates for the fabrication of graphene/polymer composites. However, the synthesis of GO using strong oxidants reduces the conductive properties compared to rGO and graphene. The appropriate choice of the GO reducing agent is crucial for the reaction efficiency, with dopamine (DA) being an eco-friendly and non-toxic alternative with high reduction capacity, improving material properties. On the other hand, DA also behaves as a hydrophilic coating agent on the rGO surface due to self polymerization to polydopamine (PDA), allowing functionalization with other molecules and/or biomolecules. Based on the above, the aim of this study was to evaluate and study the optimal conditions of the process in reducing GO by DA, and based on the yield, composition, and reactivity, analyze the factors through a design of experiments to improve material properties. The design responses were determined according to material characterization. Characterization techniques by FT-IR, XRD, SEM, and EDS, in addition to yield, allowed for qualitative and quantitative information on the composition and structure of the material. Successful reduction of GO by DA was confirmed, reflected in a decrease in the intensities of peaks corresponding to oxygen containing groups in FTIR in rGO samples. XRD analysis showed that diffraction peaks shifted after reduction due to the elimination of oxygenated functional groups, and an increase in C/O ratio was observed in elemental analysis of rGO compared to GO. Statistical analysis of the experimental design showed that in the dialysis process, a higher volume of water decreases the PDA concentration, and frequent changes or prolonged dialysis time are not necessary. It was also found that a reaction time of 6 hours and a reaction temperature of 80°C improve the efficiency of reduction at a high GO:DA ratio (3:2). Optimizing dialysis and reduction protocols allowed for faster and more effective synthesis of the compound, while ensuring reproducibility and material quality.
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