development of functionalized graphene for building material

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

mailto:[email protected]


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


Our research group

Nan Wang Dea Nykrem Dr Lilei Ye Dr Bijan Adl-Zarrabi Prof Johan LiuProf Luping Tang


The Blueprint of Graphene Flagship`


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


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


Chemical vapor deposition of graphene

Black magic II

Sketch of graphene growth

Graphene growth mechanism8


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.


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


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


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


Graphene for heat dissipation


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


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.


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.


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


Graphene Vs Workability of Cement


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.


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


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


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


Q&C

development of functionalized graphene for building material

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