Interfacial thermal conductance (ITC) receives enormous consideration because of its significance in determining thermal performance of hybrid materials, such as polymer based nanocomposites. In this study, the ITC between sapphire and polystyrene (PS) was systematically investigated by time domain thermoreflectance (TDTR) method. Silane based self-assembled monolayers (SAMs) with varying end groups, -NH2, -Cl, -SH and -H, were introduced into sapphire/PS interface, and their effects on ITC were investigated. The ITC was found to be enhanced up by a factor of 7 through functionalizing the sapphire surface with SAM, which ends with a chloride group (-Cl). The results show that the enhancement of the thermal transport across the SAM-functionalized interface comes from both strong covalent bonding between sapphire and silane-based SAM, and the high compatibility between the SAM and PS. Among the SAMs studied in this work, we found that the ITC almost linearly depends on solubility parameters, which could be the dominant factor influencing on the ITC compared with wettability and adhesion. The SAMs serve as an intermediate layer that bridges the sapphire and PS. Such a feature can be applied to ceramic-polymer immiscible interfaces by functionalizing the ceramic surface with molecules that are miscible with the polymer materials. This research provides guidance on the design of critical-heat transfer materials such as composites and nanofluids for thermal management.
Bibliographical noteFunding Information:
This work was supported by the National Natural Science Foundation of China (Grant Nos. 51373184 and 51336009), the National Plan for Science & Technology Support, China (Grant No. 2014BAC03B05), the MoST (Ministry of Science and Technology) 973 Research Programme (Grant Nos. 2014CB931803 and 2012CB933801), and Ministry of Science and Technology of the Peoples Republic of China (Grant No. 2013YQ120355). X. Wang would like to acknowledge the support from UMN CSE startup.
© 2016 American Chemical Society.
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- interfacial thermal conductance
- organic-inorganic interface
- solubility parameter
- time domain thermoreflectance