Abstract
Three-dimensional (3D) structures obtained from 2D material have attracted huge attention owing to the outstanding electro-mechanical and thermal properties of 2D material. The interest has expanded to integrate the 2D material into a 3D printing structure to form a periodically cellular foam. Today, a dozen new 2D materials exist, including graphene, MXenes, and Transition Metal Dichalcogenide (TMD).The main objective of this work is to characterize the performance of triply periodic minimal surfaces (TPMS) using a 3D structure fabricated from 2D material. Lattices based on (TPMS), which have been receiving increasing interest due to advances in additive manufacturing, are known now to be outperforming other cellular materials in several properties, enabling a wider multifunctionality. TPMS have recently received increasing interest [4] in several applications including heat sinks [6], thermal energy storage [7], catalytic converters [8, 9], tissue engineering [10, 11], lightweight multifunctional cellular materials and structures [12-16], and membrane feed spacers [17]. TPMS structures have shown superior performance in these applications compared to conventional lattices. So, the incorporation of TPMS structures with the 2D material will result in producing a 3D TPMS structure from 2D material with enhanced electrical, thermal and mechanical properties. Several studies focus on fabricating 3D structures from 2D material with different techniques. The latest technique for designing a 3D structure from 2D material has been employed to fabricate a polymer template based on TPMS structures using an additive manufacturing (AM) technique that can be used as a template. This work employs the self-assembly hydrothermal and sacrificial template methods to fabricate the 3D structure from graphene as 2D material. Ligament- and sheet-network structures based on TPMS were fabricated and used as templates with different periodicities and relative densities. The work also extended to fabricate 3DGS based on 3D printed stochastic TPMS networks that are used as a template in order to compare their multifunctional properties with the 3DGS based on TPMS structures.
Advanced material characterization techniques such as scanning electron microscopy (SEM) and micro-computed tomography (micro-CT) scan were used to visualize the internal structure and study the difference in pore size and strut thickness between the 3D printed structures and fabricated graphene structures. X-ray diffraction (XRD) and Raman spectroscopy were used to verify the presence of the graphene material, while thermogravimetric analysis (TGA) was used to assess the quantity of residual polymer and the stability of the fabricated structures. A series of tests were performed to measure the electro-mechanical and thermal properties of the 3D graphene structures (3DGS). The tests findings led us to study and investigate the ability to graft the 3DGS with a second conductive filler material such as carbon nanotubes (CNTs) and silver nanowires (AgNWs), thus aiming to enhance the properties of the 3DGS, especially electrical conductivity, making an efficient structure for electromagnetic shielding (EMI) applications.
Results show that tube-ligament networks based on IWP structure surpass other ligament networks in terms of mechanical, thermal, and electrical properties. The 3DGS based on sheet networks outperformed tube-ligament networks in terms of mechanical properties. The 3DGS fabricated using CNTs, and AgNWs show higher electrical conductivity as well as higher EMI shielding efficiency. It is observed that the results obtained in this work are comparable to the other cellular graphene foams. It is greater than graphene lattices using other techniques, including hydrothermal process [18-20], 3D printing process [21, 22] and dip-coating [18]. Also, the measured specific values are in good agreement with the values for the graphene structures fabricated using CVD [18, 23].
This research contributes significantly to employing several engineering applications such as; electromagnetic shielding, pressure sensors, and passive air-cooling using advanced 3D TPMS structures fabricated from 2D material.
Date of Award | Dec 2022 |
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Original language | American English |
Keywords
- 3D graphene structure
- triply periodic minimal surfaces (TPMS)
- Additive manufacturing
- self-assembly hydrothermal method
- silver nanowires (AgNWs)
- carbon nanotubes (CNTs)