Electro-elastic and piezoresistive behavior of flexible MWCNT/PMMA nanocomposite films prepared by solvent casting method for structural health monitoring applications

Electrical, mechanical and piezoresistive behavior of flexible thin films of multi-walled carbon nanotubes (MWCNT) embedded in poly(methyl methacrylate) (PMMA) matrix are investigated for structural health monitoring applications. Three sets of MWCNT/PMMA nanocomposite thin films at various weight percentage of MWCNT are fabricated using solvent casting method. Dichloromethane (DCM) is used as a solvent. The percolation threshold for electrical conductivity is found to be 3 weight percentage of MWCNT. The mechanical properties of thin films are evaluated via monotonic uniaxial tensile test. The rate of loading is 1 mm/min and applied load and crosshead displacement are sampled at 10 Hz frequency. Experimental results showed that addition of 10 weight percentage of MWCNT leads to a significant improvement in the tensile strength of PMMA by 291% and tensile strain by 122%. The piezoresistive behavior at different weight percentage of MWCNT is evaluated and highest gage factor of 4.37 is achieved at the percolation threshold.