Properties of Fullerenes Aggregates

In the previous section, the formation and characteristics of single fullerene molecules were reviewed. In this and the following sections, the formation, characteristics, and properties of solid aggregates of fuiierenes are examined. Fuiierenes aggregates are a new discovery their characterization and the determination of their properties is still at an early stage and much work remains to be done. Yet what has been accomplished so far shows the striking potential of these materials. 

The C70 aggregates are different as they have a hexagonal structure with lattice parameters a = 1.063 nm and c = 1.739 nm.O f 

Mechanical Properties. Ceo aggregates are considered the softest of the solid phases of carbon.O I However, calculations show that, under high pressure when compressed to less than 70% of its original volume, they could be harder than diamond.i l They have high impact strength and resilience. They should also have high lubricity since the molecules are bonded by van der Waals forces in all planes which should allow the molecules to slip readily over each other in a manner similar to the ab planes of the graphite crystal. 

The aggregates have a constricted micropore structure with a micropore width of 1.19 -1.26 nm and a relatively high internal surface area (131.9m2/g).[iei 

Semiconductor Properties. Calculations indicate that C o could be a direct band-gap semiconductor similar to gallium arsenide. However, the semiconductor properties have yet to be determined. 

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