0Chalmers University of Technology
Development of Functionalized Graphene for Building Material
ApplicationNan Wang,
[email protected],2016-09-20
Supervisors:, Lilei Ye, Bijan Adl-ZarrabiExaminer: Johan Liu, Luping Tang
1Chalmers University of Technology
Development of Functionalized Graphene for Building Material Application• Background: What is graphene and its potential
applications• Goal of our current research• Mechanical strength of the FGO composite • Microstructure analysis• Concluding remarks
Outline
Chalmers University of Technology
... situated on the beautifulWest Coast of Sweden
in the centre of Göteborg- close to Europe
Sweden
Göteborg
Flagship GrapheneWith a budget of EUR one billion, the Graphene Flagship is tasked with taking graphene from the realm of academic laboratories into European society in the space of ten years, thus generating economic growth, new jobs and new opportunities for Europeans as both investors and employees.
Jari Kinnaret, coordinatorprofessor at MC2
4Chalmers University of Technology
Our research group
Nan Wang Dea Nykrem Dr Lilei Ye Dr Bijan Adl-Zarrabi Prof Johan LiuProf Luping Tang
5Chalmers University of Technology
The Blueprint of Graphene Flagship`
6Chalmers University of Technology
Graphene
K. S. Novoselov, et al., Nature (2012)
Grpahene’s properties: • graphene is composed by one or few
atomic layers of sp2-bound hexagonal carbon lattice
• graphene is 106 *more conductive than copper
• graphene conducts heat even better than diamond (~5000 W/mK)
• graphene is mechanically robust and highly flexible
• graphene has large surface areas
Fabrication methods• Mechanical exfoliation• Chemical vapor deposition• Liquid phase exfoliation • Chemical exfoliation
7Chalmers University of Technology
石墨胶带
硅片
Mechanical exfoliationThe first method developed for graphene fabrication. using tapes to peel off individualgraphene from graphite flakes.Advantages: high qualityDisadvantages: time consuming, low efficiency
8Chalmers University of Technology
Chemical vapor deposition of graphene
Black magic II
Sketch of graphene growth
Graphene growth mechanism8
9Chalmers University of Technology
Liquid exfoliation process by shear mixing
The mixing head is composed by a four-blade rotor sitting within a fixed stator (D rotor-stator = 100 μm). The diameter of the rotor is 32 mm. • Maximum speed: 8000 rpm• Maximum volume: 12 L
High efficiency, low power consumption, minimum temperature increase, mass production.
10Chalmers University of Technology
Chemical exfoliation of graphene
3.583 nm10.472 nm
Simulation results of interlayer spacing of two-layer graphene sheets and graphene oxide.
Chemical oxidation of graphite
(Hummers method)
Liquid phase exfoliation
Chemical reduction of graphene oxide
11Chalmers University of Technology
Graphene as anode materials for lithium ion battery: improve the capacity
Anode materials play a key role in the battery, they take over about 15% of the battery cost. Due to the large surface area and existence of micro-pores, graphene could significantly improve the battery capacity to 740-780 mAh/g, which is about two times higher than traditional anode materials.
Material Capacity
Graphite
Graphite/GrapheneGraphene
12Chalmers University of Technology
Graphene as conductive materials in electronic field
• Graphene has superior electron mobility (100 times higher than silicon),
• super high transparence (2.3% absorption for single layer)
• strong tensile strength (no damage under 20% stretching ratio),
• flexible, will be the most important material for display and transistor applications
13Chalmers University of Technology
Graphene for heat dissipation
14Chalmers University of Technology
Graphene as sensor materials
Graphene has super large surface areas and can be easily modified byall kinds of small molecules, biostructures and gas molecules todevelop chemical and biological sensors
15Chalmers University of Technology
Graphene as the anti-bacterial materials
Graphene can cause severe damage to the cell membrane and kill bacteria whilst has very small toxicity to the mammalian cells, which is a new kind of green antibiotics.
16Chalmers University of Technology
Graphene for environmental protection
Graphene and its derivative materials have strong absorption tosmall molecules, which could be widely used for water filtration,sea water desalination, and wastewater treatments.
17Chalmers University of Technology
Development of functionalized graphene oxide for cement reinforcement
Resulting in revolutionary improvement of fundamental properties
Features of functionalized graphene oxide (FGO):
Water soluble materialLarge surface areasBuild strong connection between graphene domains and cement hydrates via covalent bonds
• High tensile strength due to the high flexibility of graphene
• Less shrinkage due to the high stability of graphene
18Chalmers University of Technology
Graphene Vs Workability of Cement
19Chalmers University of Technology
Morphology changes of FGO after mixing with cement
Within 10 minutes, the surface of FGO has been fully occupied by large amount of flower-like crystals. They are tightly bonded on the graphene oxide surface.
Morphology change of FGO after mixing with diluent cement aqueous solution for 10 minutes
Benefits of FGO: • These crystals would act as nucleation sites for further crystal growth. The large amount
of crystals formed at the beginning of hardening process would refine the crystal structures of cement.
• The further growth of cement crystal would surround the surface of FGO, which can lead to a tight combination of cement with graphene domain.
20Chalmers University of Technology
Mechanical strength of FGO enhanced cement
• Compressive strength was improved about 44% with 0.15 wt% of FGO16% with silica NPs (3 wt%), 5% with pure GO (0.45 wt%)
• Flexural strength was improved about 20% with 0.15 wt% of FGO -6% with pure GO (0.45 wt%)
Result and Discussion
These results show the significant reinforcing effect of FGO compared to silica nanoparticles and pure GO.
W/C=0.5
21Chalmers University of Technology
Workability study of FGO to cement pasteResult and Discussion
Cement:Limestone:Water:SP= 100:16.7:40:1.23
Cement:Limestone:Water:FGO:SP= 100:16.7:40:0.3:1.17
Yield stress = 1.3 Pa Yield stress = 1.1 Pa
22Chalmers University of Technology
Refining Microstructure with FGO
Reference (plain cement ): needle-like crystals creats large interspace and voids inside the concrete, which limited the strength improvement
Cement with 0.15% FGO: Denser microstructure with addition of FGO supplies the base for increased mechanical properties and durability of cementitious composites
Result and Discussion
23Chalmers University of Technology
Q&C
Top Related