Graphene Nanoplatelet Production Through Non-Ionic Surfactant-Assisted Exfoliation of Graphite
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Authors
Giglio, Cameron
Date
Type
thesis
Language
eng
Keyword
Graphene , Liquid Phase Exfoliation , Ultrasonication , Shear Mixing , Surfactant , Pluronic F127 , Graphene Nanoplatelet
Alternative Title
Abstract
Liquid phase exfoliation of graphite is performed using ultrasonication and shear exfoliation to produce graphene nanoplatelets (GNPs). Ultrasonication is performed using a tip sonicator under power loads ranging from 35-100% amplitude (corresponding to power of 9-36 W) and concentrations of Pluronic® F127 surfactant in water ranging from 1-15 wt%, under batch and sequential addition of surfactant modalities. Shear exfoliation is achieved using a lab scale shear mixer operated with rotor speeds ranging from 1500 rpm to 8000 rpm and Pluronic® F127 concentrations ranging from 1-10 wt%. Ultrasonication exfoliation demonstrated GNP concentrations as high as 3.01 mg·mL-1 at 100% amplitude and 15 wt% surfactant concentration. The average particle sizes of the nanoplatelets, were approximately 200-550 nm for all exfoliation methods as estimated through dynamic light scattering (DLS). Transmission electron microscopy (TEM) characterization revealed particle sizes on the order of hundreds of nanometers in lateral dimension. Ultrasonication resulted in few-layer graphene, with thickness ranging from 4-77 nm as measured by Atomic Force Microscopy (AFM) and aspect ratios of 36-96. Shear mixing generated multi-layer graphene, with thickness ranging from 6-11 nm and aspect ratios of 25-72.
Both processes were modeled using dimensional analysis, which revealed that high yields can be achieved beyond specific thresholds of power density input, rotation speed, and surfactant concentration. Based on the results, shear mixing presents itself as a promising method that can be readily scalable above a rotor speed threshold.
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ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.