Fabrication and Thermo-Electro-Mechanical Behavior Investigation of Various Pore Size Graphene Lattices Based on 3D-Architected Gyroid Scaffolds

  • Abdulrahman Jaber

Student thesis: Master's Thesis

Abstract

The fabrication of free-standing three-dimensional (3D) graphene structures is an important objective to exploit the superior properties of single graphene layer in many applications. The challenges against development of such structures are the pore size control, architectural adaptability, and scalability. In this study, reduced graphene oxide structures (RGOSs) with various pore sizes were fabricated using self-assembly assisted hydrothermal method. 3D printed polymer gyroid was used as sacrificial scaffold. The fabrication involved mixing graphene oxide (GO) solution with hydrazine to obtain chemically reduced GO (rGO). The scaffold was coated using the rGO solution. Finally, it undergone thermal etching to remove the polymer. Samples with different number of unit cells (N), unit cell sizes (S), and scaffold relative densities (R) were studied. SEM images showed smooth polymer scaffold surfaces and rougher RGOSs faces. Volume fractions were computed using micro-CT-scan. Carbon and oxygen compositions of 88-94% and 5.7-12% respectively were detected using EDS. Raman spectrums showed rGO peaks around 1339 cm-1 (D peak), 1571 cm-1 (G peak), and 2699 cm-1 (G peak). The rGO presence was also proved using XRD as the rGO peaks were appeared between 2θ = 25.5˚~ 26˚. The FT-IR ensured GO reduction from complete removal of hydroxyl groups. However, some traces of polymer bonds were observed. Electrical conductivity tests were done employing van der Pauw principle. Moreover, thermal conductivity tests using hot disc method were achieved. The electrical and thermal conductivities displayed similar trends as they were decreased when N, S, and R increased. The maximum measured electrical conductivity was 28.6 S/m. While the highest thermal conductivity obtained was 2.98 W/mK. The mechanical properties showed reduction trends with increased N and S but increased with R. The highest Young's modulus recorded was 10.8 MPa for the 40% R sample where the high polymer residuals were anticipated to cause it.
Date of AwardMay 2021
Original languageAmerican English

Keywords

  • Graphene 3D structures
  • Additive manufacturing
  • Triply periodic minimal surfaces
  • Reduced graphene oxide coating
  • Stereolithography.

Cite this

'