Graphene oxide (GO) films have a great potential for aerospace, electronics, and renewable energy applications due to their low cost and unique properties. For structural applications, they can achieve an exceptional combination of damping and stiffness. This study investigates the effect of packing density, reduction, and water removal on stiffness and damping of graphene oxide films. GO sheets dispersed in water are passed through a filter and deposited on a removable substrate. Through variations of the film fabrication process, films of both GO and reduced GO (rGO) are produced with varying levels of packing. Heat treatment is also used to remove the water in half of the films. The degree of packing is assessed through film density calculations. Microscopy as well as Raman and X-ray spectroscopy are used to measure the degree of packing while Dynamic Mechanical Analysis (DMA) is used to quantity mechanical damping and storage modulus of specimens in tension. Correlating mechanical properties to structure of films revealed new understanding of damping and stress transfer mechanisms in these materials. Optimal structures resulted in superior combinations of stiffness (18 GPa) and damping (0.14), potentially paving the way for using GO based films in advanced structural applications.
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INVESTIGATING STRESS TRANSFER AND FAILURE MECHANISMS IN GRAPHENE OXIDE-CELLULOSE NANOCRYSTALS FILMS
Graphene oxide (GO) films have great potential for aerospace, electronics, and renewable energy applications. GO sheets are low-cost and water-soluble and retain some of Graphene’s exceptional properties once reduced. GO or reduced GO (rGO) sheets within a film interact with each other via secondary bonds and cross-linkers. These interfacial interactions include non-covalent bonds such as hydrogen bonding, ionic bonding, and π-π stacking. Stress transfer and failure mechanisms in GO and rGO films, specifically how linkers affect them, are not well understood. The present study investigates the influence of inter-particle interactions and film structures, focusing on hydrogen bonds introduced via cellulose nanocrystals (CNC), on failure and stress-transfer of the GO and rGO films. To this end, GO films with CNC crosslinkers were made, followed by a chemical reduction. The few-micron thick films were characterized using tensile testing. All tested films exhibited a brittle failure and achieved tensile strengths and modulus in the ~40-85 MPa and ~3.5-9 GPa ranges, respectively. To reveal stress transfer mechanisms in each sample, tensile in-situ Raman spectroscopy testing was carried out. By monitoring the changes in bandwidth and position of Raman bands while stretching the film, useful information such as sheet slippage and cross-linker interactions were gathered. The addition of CNC enhanced modulus but degraded strength for both GO and rGO films. Interestingly, the Raman G-peak shift at failure, indicative of stress transfer to individual GO/rGO particles, is commensurate with the films’ strengths. Correlating these results with the structure and composition of different films reveals new understanding of stress transfer between GO/rGO particles, paving the way for the scalable manufacturing of strong and stiff GO-based films.
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- Award ID(s):
- 2015732
- NSF-PAR ID:
- 10324596
- Date Published:
- Journal Name:
- PROCEEDINGS OF THE AMERICAN SOCIETY FOR COMPOSITES—THIRTY-SIXTH TECHNICAL CONFERENCE ON COMPOSITE MATERIALS
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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This article is categorized under:
Structure and Mechanism > Molecular Structures
Structure and Mechanism > Reaction Mechanisms and Catalysis
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.12783/asc36/35862
