I report on the study of the electrical and mechanical effects of the inclusion of a thin layer of multiwalled carbon nanotubes (MWCNT) into the surface of polydimethylsiloxane (PDMS) as a method of creating an electrically actuated, flexible microfluidic valve. Samples of PDMS loaded with various surface loadings of MWCNT on the surface are prepared and tested using a uniaxial tension tester, combined with a four point probe electrical test. In contrast with other works reporting inclusion of MWCNT in the bulk of the material, I have found that inclusion of the MWCNT on the surface only has no discernable effect on the mechanical properties of the PDMS samples, but causes a significant and repeatable change in the electrical performance. I have also found that a loading of 4.16 g/m2 results in an electrical resistivity of 7.31\u038710-4 ohms\u0387cm, which is 200% lower than that previously reported for bulk inclusion samples. The microstructure of the MWCNTs was found to consist of both individual fibers and spherical clumps of fibers. I suggest that, due to the microstructure of the MWCNTs used in this study, the mechanical properties can be modeled as a thin layer of particulates, while the electrical properties can be modeled as a thin bed of bulk MWCNTs.
Microfluidic devices--Materials, Nanocomposites (Materials), Nanotubes, Polydimethylsiloxane.
Level of Degree
First Committee Member (Chair)
Second Committee Member
Third Committee Member
Sandia National Laboratories
Salzbrenner, Jeffrey. "Mechanical and electrical properties of carbon nanotubes surface-stamped on polydimethylsiloxane for microvalve actuation." (2012). https://digitalrepository.unm.edu/me_etds/56