Obtención de grafeno mediante exfoliación en fase líquida y optimización de la parte experimental a través de tratamiento hidrotérmico.

Abstract

The objective was to obtain graphene by exfoliation of graphite in liquid phase and its characterization obtained by Ultraviolet Spectroscopy (UV), Infrared (IR) and Scanning Electron Microscopy (SEM). The influence of sonication time, time and spin speed was studied using two different solvents with different boiling point and coefficient dispersive, i.e., ethanol and dimethyl formamide maintaining a constant volume of 10 ml, for the experimental design 3 solute-solvent were defined (0.5: 1, 1: 1 and 2: 1). Each ratio was subjected to sonication three times (2, 5 and 7 hours). The sonicated samples were centrifuged for 5, 10 and 20 minutes at an angular speed of 500 rpm and 1000, reespectively. Graphene particles were generated in each suspension, in which it was found that the centrifugation speed caused a greater impact on the concentration of graphene. Through the UV spectroscopy it was determined the characteristic peak around 280 nm corresponding to π-π* transition, the one which is characteristic of graphene. The concentration achieved is 60 µg/ml in ethanol, and 40 µg/ml for Dimethyl-formamide (DMF). The infrared spectrum of the suspensions in ethanol showed the presence of hydroxyl groups mainly around 3200 cm -1, whereas in DMF were detected amino groups, carbonyls and nitro compounds in ranges 1000 to 1500 cm-1. Morphological characterization was determined by SEM, which shows transparent sheets having smooth surfaces with jagged edges dimensions of the order of 2 µ.m. A thermal shock is not feasible to optimize the process, because the results presented by this method does not suffer a significant improvement compared to the normal process.