Preparation,Micro-Patterning and Electrical Characterization of Functionalized Carbon-Nanotube Polydimethylsiloxane Nanocomposite Polymer |
| |
Authors: | A. Khosla B. L. Gray |
| |
Affiliation: | Microinstrumentation Lab, School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada. V5A 1S6 |
| |
Abstract: | Summary : We present the preparation, improved micro-patterning, and electrical property characterization of COOH- functionalized mutli-walled carbon nanotube (MWCNT) and polydimethylsiloxane (PDMS) conductive nanocomposite polymers that can be employed for lab on a chip applications. The nanocomposites are prepared by mixing functionalized MWCNTs into an uncured PDMS matrix and employing high frequency ultrasonics (∼ 42-50 kHz) using a horn tip probe. The prepared nanocomposites are micromolded using soft lithography techniques down to a feature size of 25 µm against a micropatterned SU-8 polymer master. An array of peg like microstructures have been fabricated with a radii of 25 µm and height of 100 µm, that are embedded on a non-conductive PDMS substrate using novel and improved fabrication techniques. The percolation threshold of the prepared nanocomposite is achieved at 1.5 weight percentage (wt.%) of COOH- functionalized MWCNT in the PDMS matrix. Resistivity levels at 2 wt.% of functionalized MWCNTs are 62 Ω-cm or better, which is an improvement over our previously reported nanocomposite resistivity value of 100 Ω-cm at 2 wt.% of nonfunctionalized MWCNT's in a PDMS matrix. The nanocomposites also have fairly uniform dispersion and no agglomeration of COOH- functionalized MWCNT as shown by SEM analysis. Furthermore, the nanocomposites show a negative temperature coefficient of resistivity (NTCR), making them ideal candidates for micropatternable temperature microsensors for lab on a chip systems. |
| |
Keywords: | conducting polymers elastomers functionalized carbon nanotubes high frequency ultrasonics nanocomposite soft lithography |
|
|