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Thermoelectric Properties of Polydimethylsiloxane (PDMS) - Carbon Nanotube (CNT) Composites

Athikam, Pradeep kumar
http://orcid.org/0000-0003-0330-2744
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1595848598234548

Abstract Details

2020, MS, University of Cincinnati, Engineering and Applied Science: Materials Science.
Energy consumption of the world is increasing rapidly, but nearly two-thirds of energy consumed is being wasted in the form of heat. Thermoelectric materials convert waste heat into electricity which can be used to improve the efficiency of existing systems and reduce the energy consumption. Currently most of the thermoelectric materials are inorganic semiconductors that are expensive, heavy, non-flexible and not scalable in production. They also suffer from lower efficiencies because their thermoelectric properties that together determine the efficiency are mutually coupled, i.e. increasing one factor negatively effects the other property. This has been one of the major factors limiting their success at the market level for decades. Recently, introduction of nanotechnology into bulk thermoelectric materials has shown promising results to improve their properties. Exploring possible organic materials as replacements for inorganic semiconductor materials has also given a new hope for improving the thermoelectric performances with advantages such as light weight, low cost and scalability for future energy applications. Decoupling of the thermoelectric properties may be possible by dispersing nanomaterials such as carbon nanotubes (CNTs) in organic material matrix. In this work, we dispersed single-walled CNTs in non-conducting polydimethylsiloxane (PDMS) elastomer matrix to create a versatile flexible thermoelectric material. PDMS was chosen as the matrix because of its many advantages such as its scalability, solution processability, low cost, light weight, high flexibility, biocompatibility and low thermal conductivity. PDMS is originally insulating, but by dispersing CNTs in it, percolation networks can be created to achieve a high electrical conductivity, which is required for high thermoelectric performance. Single-walled carbon nanotubes are chosen as conducting media because of their excellent electrical and thermal properties as well as easy dispersion in polymers. PDMS and CNTs were dispersed in a common solvent chloroform and, shear mixing and ultrasonication are used for uniform dispersion of the CNTs. Solvent is gradually evaporated in the next step to get uniform and thick PDMS-CNT composite samples. Varying concentration of CNTs and careful control of processing steps has given a seebeck coefficient of ~70 µV/K and an electrical conductivity of ~50 S/cm. This material can be used to harvest heat from low grade thermal energy systems such as the human body at room temperature to power electronics such as sensors in human body or wearable watches. The developed material is low cost and can be molded into a thickness of few mm for scalable production.
Je-Hyeong Bahk, Ph.D. (Committee Chair)
Mark Schulz, Ph.D. (Committee Member)
Donglu Shi, Ph.D. (Committee Member)
83 p.
Materials Science
Thermoelectric Materials; Nanocomposites; Energy harvesting; Carbon Nanotube Networks; Flexible thermoelectrics; Polymer composites

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Citations

  • Athikam, P. K. (2020). Thermoelectric Properties of Polydimethylsiloxane (PDMS) - Carbon Nanotube (CNT) Composites [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1595848598234548

    APA Style (7th edition)

  • Athikam, Pradeep kumar. Thermoelectric Properties of Polydimethylsiloxane (PDMS) - Carbon Nanotube (CNT) Composites. 2020. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1595848598234548.

    MLA Style (8th edition)

  • Athikam, Pradeep kumar. "Thermoelectric Properties of Polydimethylsiloxane (PDMS) - Carbon Nanotube (CNT) Composites." Master's thesis, University of Cincinnati, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1595848598234548

    Chicago Manual of Style (17th edition)

ucin1595848598234548
204
© 2020, some rights reserved.Creative Commons License Thermoelectric Properties of Polydimethylsiloxane (PDMS) - Carbon Nanotube (CNT) Composites by Pradeep kumar Athikam is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by University of Cincinnati and OhioLINK.