(Georgia Institute of Technology, 2010-03-16)
Tzanavaris, Christopher
This study explores the use of polydimethylsiloxane (PDMS) reinforced with vapor-grown carbon fibers (VGCF) as a strain sensor. The operational principal of the nanocomposite sensors with VGCF content above the percolation threshold is that as the material is strained, its conductivity decreases because the conductive network of carbon fibers disconnects whereas upon release of the strain the conductivity increases. However, due to energy dissipation in the PDMS there is a big lag in the conductivity during the loading-unloading cycle that leads to sensors with no reproducible strain-conductivity behavior. This challenge is overcome by tuning the monomer to curing agent ratio used to formulate the PDMS matrix.