Fabrication of Pressure-Sensitive Multiwalled Carbon Nanotubes-Poly(methyl methacrylate) Nanocomposites for Pressure-Sensing Applications

Abstract

In this study, we fabricated novel, pressure-sensitive nanocomposites through two different methods. These materials were thoroughly evaluated and compared with one another. Multiwalled carbon nanotubes (MWCNTs) were added to thermoplastic polyurethane (TPU) by melt mixing and to Poly(methyl methacrylate) (PMMA) beads of different sizes to make the first type of sample. A solution mixing method was used to coat PMMA beads of different sizes with MWCNTs, and then the TPU polymer was added to make another nanocomposite. The effects of different PMMA bead sizes on the pressure-sensing properties of both nanocomposites were studied by applying different external loads. PMMA beads were used to increase the internal volume and achieve a segregated electro-conductive network structure, leading to an early percolation threshold. Scanning electron and Raman microscopy were used to study the morphology of the nanocomposites. The electrical and thermal conductivities of the nanocomposites were also investigated under different applied loads, and the two methods were compared. The electrical responses of the nanocomposites under different applied pressures demonstrated a linear decrease in the electrical resistivity with increasing applied external load, thereby confirming that these novel nanocomposites are suitable for use as pressure-sensing materials; they also show repeatability in their electrical response when an external load was applied repeatedly. These materials represent ideal candidates for use in pressure-sensitive devices.