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Interfaces play a very important role in a variety of fields. Properly tailoring the properties of an interface material can lead to unique system-level properties. For instance in the problem of high-through put heat transfer from a Si die (processor) to a Cu heat sink, Figure (a), we fabricated micro- and nanothermal interfaces via Glancing Angle Deposition (GLAD) that were comprised of intertwinned Cu helices, Figure (b). GLAD is a scalable deposition method that can be applied to a variety of metal and ceramic materials. The resulting thermal interface materials provided a set of orthogonal properties: High thermal conductivity, which is typical of metals for example, combined with ultra-low mechanical stiffness, which is typical of thermoplastics above Tg. Insertion of this nanothermal interface helped to aleviate the thermal stresses due to the thermal mismatch between Si and Cu. A material meeting these two objectives would reside in the empty space of the log-log Ashby chart, Figure (c). GLAD is a flexible method that allows tailoring the geometry of the individual helices and spacing and, as a result, the mechanical properties of the thermal interface, Figure (d).

This methodology was utilized to provide shielding of thin film photovoltaics (2 µm) against large strains imposed by carbon fiber laminates, and to control surface wrinkling by tuning the wrinkle wavelength in geometry and material constraint systems, as well we provide a unique method to provide anisotropic wrinkling that has not been possible before. The publications below tell the story...

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                                                                                                   Related Publications

1. K-K. Hung and I. Chasiotis, “Control of Surface Wrinkling through Compliant Nanostructured Interfaces,” Advanced Materials Interfaces 9 (3), p. 2101583, (2021).

2. K-K. Hung and I. Chasiotis, “Control of Substrate Strain Transfer to Thin Film Photovoltaics via Interface Design,” Solar Energy 255, pp. 643-655, (2021).

3. D. Antartis, H. Wang, J. Wang, S. J. Dillon, H.B. Chew, I. Chasiotis, “Nanofibrillar Si Helices for Low-Stress, High-Capacity Li+ Anodes with Large Affine Deformations,” ACS Applied Materials and Interfaces 11, pp. 11715−11721, (2019).

4. D. Antartis, R. Mott, D. Das, D. Shaddock, I. Chasiotis, “Cu Nanospring Films for Advanced Nanothermal Interfaces”, Advanced Engineering Materials 20(3), pp. 1700910(1-6), (2018).

5. D. Antartis, R. Mott, I. Chasiotis, “Si Nanospring Films for Compliant Interfaces,” Journal of Materials Science 53(8), pp. 5826-5844, (2018).

6. D. Antartis, I. Chasiotis, “Individual Helical Nanostructures for Ultra-compliant Interfaces”, Materials and Design 144, pp. 182-191, (2018).