Electrical percolation in nanostructured polymeric systems
Arianna Watters
Advisor: Palmese
1-ethyl-3-methylimidazolium dicyanamide is a room temperature ionic liquid that
interacts with SWNTs through weak Van der Waals interactions to disrupt bundles
while concurrently initiating an anionic polymerization with the epoxy matrix,
creating a thermosetting composite system. The small particle size of SWNT
minimizes disruption of the polymer matrix, while high surface area increases the
interactions between the polymer and the SWNTs. Tube dispersion is monitored by
electrical conductivity measurements, conductivity and filler loading are related by
a power law equation and compared to theoretical percolation.
The resulting composite system shows an exponential increase in conductivity with
increasing filler loading and an ultralow critical percolation of 4.29x10-5 volume
fraction. Experimental deviation from theoretical percolation is illustrated by SEM
imaging, revealing a fracture surface with dispersed SWNTs and small areas of
SWNT agglomerations. This non-volatile solvent process creates nanocomposites
with simplified processing and improved interfacial interactions. The
nanocomposite enables control of desired material properties including
mechanical, thermal and electrical by varying parameters such as particle size,
surface area of the nanoparticle and the strength of the interfaces.