EAGER: An Innovative Way to Enhance Cross-Plane Thermal Conductivity of Polymer-Based Thin Films

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#1641103Tain, ZhitingOne of the most critical problems with current electronic devices is thermal management - removing heat from nanoscale regions. The heat intensities increase steeply, created by an exponential increase in power densities and a significant decrease in device sizes. Thermal management becomes a critical bottleneck for the advancement of a variety of important defense, space and commercial applications. Developing energy-efficient cooling technologies is the key to improving energy saving, performance, reliability and lifetime of electronic devices. Revolutionizing thermal interface materials is crucial for the development of heat rejection technologies because the thermal resistance of thermal interface materials comprises a significant fraction of the total thermal resistance from device to air. Better thermal interface materials with high cross-plane thermal conductivity allow reduction of size, cost and weight of other components. This project proposes to study polymer-based thin films with vertically aligned or confined chains as a potentially innovative solution to thermal interface materials. By improving the efficiency of heat rejection at the interface, the proposed work will notably contribute to global sustainable energy solutions. The research findings will be disseminated to a broader audience through 1) outreach activities for precollege students 2) undergraduate research activities and casual talks and 3) collaboration with industry partners. Building on current success, the PI will make every effort to promote academic diversity and recruit underrepresented students.The research objective of this proposal is to test the hypothesis that polymer chains, which are vertically aligned or confined in vertically aligned nanochannels, can enhance the cross-plane thermal conductivity of thin films and to understand the optimal conditions for enhancement, if any. The goal is to accelerate rational design of polymer or polymer-inorganic hybrid thin films with high cross-plane thermal conductivity for transformative thermal applications such as promising thermal interface materials for electronics thermal management. Molecular dynamics simulations will be performed to compute the thermal conductivity of thin films of our interest to 1) establish the base line comparison between vertical alignment and other orientations (horizontal alignment and amorphous films); 2) build the structure-property relation; and 3) understand the microscopic mechanisms by investigating the vibrational modes and quantifying the chain crystallinity and confinement. If the hypothesis is proven, this may open up exciting opportunities to engineer polymer-based thin films with high cross-plane thermal conductivity. The proposed study will advance the fundamental understanding of thermal transport in polymer-based thin films with vertical alignment or confinement, and answer whether the vertical alignment or confinement could potentially achieve high cross-plane thermal conductivity and how the enhancement, if any, can be optimized. The fundamental study of thermal transport processes in polymer-based thin films of this unique morphology highlights the intellectual merits of this work.