Large scale micropatterning of multi-walled carbon nanotube/polydimethylsiloxane nanocomposite polymer on highly flexible 12×24 inch substrates

Abstract

We present the large scale micro-pattering of an electrically conducting multiwalled carbon nanotube (MWCNT) polydimethylsiloxane (PDMS) nanocomposite polymer prepared by high frequency (42 kHz) ultrasonic agitation of MWCNTs in the PDMS polymer matrix. Large scale micropatterning of the MWCNT-PDMS nanocomposite is achieved via soft lithography employing a 12" x 24" poly-methyl methacrylate (PMMA, commercially known as Plexiglass) micromold. The process has a 20µm.minimum feature size. The PMMA micromold is fabricated by laser ablating 5-mm thick, 12 " x 24 " sheets using the Universal Laser System's VersaLASER© laser cutter system which employs a CO 2 laser. We have characterized and compared the resistivity of 1cm x 0.5cm x 0.5cm MWCNT-PDMS structures with varying weight percentage (wt-%) of MWCNT (1-10% wt%) in the PDMS matrix with a result that the percolation threshold is achieved at 2 wt-%. Furthermore, we have demonstrated the ability to fabricate large numbers of microelectrodes with a length of 3.0 cm, width of 500µm, and height of 400µm. The resistivity of these electrodes was found to be equal to 9.93Ωm with a deviation of approximately 10%, indicating uniformity across large areas of the substrate. We have also demonstrated a large scale 12" x 24 hybrid microfabrication process for combining micromolded MWCNT-PDMS nanocomposite microstructures with nonconductive PDMS polymer.

Conductive and flexible multi‐walled carbon nanotube/polydimethylsiloxane composites made with naphthalene/toluene mixture

“…Recently, there have been researches on finding the optimum solvents to disperse CNTs into specific polymer matrices such as PDMS . Interestingly, Liu and Choi reported that although some of the organic solvents worked well for the dissolution of PDMS and the dispersion of MWCNTs, separately, they might not work when they were used for dispersing the MWCNTs into the PDMS solution .…”

Laser-Assisted Printed Flexible Sensors: A Review

“…Significant research has been conducted on the micro-patterning of flexible materials to form sensing purposes. One of them has been explained by Khosla et al in regards to the fabrication of arrayed-sensors on flexible 12 × 24 inch substrates from MWCNTs-PDMS nanocomposites [68]. The difference of this methodology from that of the first one explained in this section lies in the use of micro-contact patterning which helps in differentiating the intensity of the induced-strain corresponding to different locations.…”

“…The measurement of the individual electrodes in the array with similar dimensions were also done to show that the resistances of these electrodes were around 9.93 Ωm. Figure 2 shows the schematic diagram of the individual steps of the fabrication process [68].…”

Using Micro-Molding and Stamping to Fabricate Conductive Polydimethylsiloxane-Based Flexible High-Sensitivity Strain Gauges

“…A common way to fabricate a conductive elastomer is by mixing flexible material and conductive material, and then curing the composites by baking. The most commonly used flexible material for conductive elastomer fabrication is polydimethylsiloxane (PDMS) [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ].…”