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NANOSCALE THERMAL CHARACTERIZATION BY SCANNING THERMAL MICROSCOPY (STHM)

Li, Yifan, Li
http://rave.ohiolink.edu/etdc/view?acc_num=akron159057422807603

Abstract Details

2020, Doctor of Philosophy, University of Akron, Chemical Engineering.
Filler technology is usually considered the most effective method to improve the thermal conductivity of polymer composites. The interface in composites is well recognized as the major thermal barrier due to the mismatch of phonon frequency in polymer and filler. How interface plays its role in thermal conduction is not fully understood yet. Scanning thermal microscopy (SThM), as a specialized variant atomic force microscopy (AFM), is used to capture the geometry information and thermal information at the same time. This unique capability makes it a proper candidate to characterize the interface thermal barriers. Microscale stiffness-probe current relationship is investigated at the composite interface which reveals that the long-range order of polymer chains surrounding the particle domains is responsible for the enhanced crystallinity and thermal conductivity of the composites. Existing SThM has the unique capability to probe qualitative thermal properties of surfaces but quantitative techniques are not available yet due to the presence of unpredictable thermal contact resistance (TCR) at tip/substrate interface. Based on the investigation on the interface properties, a quantitative model relating system thermal signal and sample thermal conductivity is proposed and verified. This unique feature endows SThM new capability in quantitative thermal analysis with spatial resolution down to the nanometer, which is critically important to quantify the thermal conduction across interfaces within composites, multi-layer structures, photovoltaic devices, microelectronics, etc. Through a further understanding of the working principle of this instrument, the thermal contact resistance (TCR) phenomenon is investigated. It indicates that the sample surface roughness is the most important factor affecting the accuracy of instrument testing, which provides the guideline for the selection of test materials in the future. SThM is further utilized as a precise characterization tool to reveal the thermal barriers in thin-film materials. Combing with the F-D characterization, SThM results clearly reveal the relationship between the thermal and micro-mechanical properties. To sum up, by studying the working principle of SThM, the application field of the instrument has been greatly expanded.
Jiahua Zhu (Committee Chair)
Yalin Dong (Committee Member)
Xiong Gong (Committee Member)
Zhenmeng Peng (Committee Member)
Rajeev Gupta (Committee Member)
140 p.
Chemical Engineering

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Citations

  • Li, Li, Y. (2020). NANOSCALE THERMAL CHARACTERIZATION BY SCANNING THERMAL MICROSCOPY (STHM) [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron159057422807603

    APA Style (7th edition)

  • Li, Li, Yifan. NANOSCALE THERMAL CHARACTERIZATION BY SCANNING THERMAL MICROSCOPY (STHM). 2020. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron159057422807603.

    MLA Style (8th edition)

  • Li, Li, Yifan. "NANOSCALE THERMAL CHARACTERIZATION BY SCANNING THERMAL MICROSCOPY (STHM)." Doctoral dissertation, University of Akron, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=akron159057422807603

    Chicago Manual of Style (17th edition)

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This open access ETD is published by University of Akron and OhioLINK.