Microfabricated ultra-thin all-polymer thermal ground planes

• Published in: Chinese science bulletin 2015-04, Vol.60 (7), p.701-706
• Main Authors: Lewis, Ryan, Liew, Li-Anne, Xu, Shanshan, Lee, Yung-Cheng, Yang, Ronggui
• Format: Article
• Language: English
• Subjects: Casing (material); Chemistry/Food Science; coatings; Deposition; Earth Sciences; Electronics cooling; encapsulation; Engineering; Flexible electronics; Ground plane; Heat pipe; Heat transfer; Heaters; Humanities and Social Sciences; hydrophilicity; Life Sciences; multidisciplinary; phase transition; Physics; pipes; Polyimide resins; polymers; Science; Science (multidisciplinary); SU-8; Thermal conductivity; Thermal ground plane; Titanium dioxide; vapors; 原子层沉积; 地平面; 壳体材料; 微制造; 氧化钛膜; 聚合物表面; 超薄
• ISSN: 1001-6538; 2095-9273; 1861-9541; 2095-9281
• DOI: 10.1007/s11434-015-0760-9

Abstract Thermal ground planes, or planar heat pipes, can provide highly effective heat transfer by utilizing phase change of an encapsulated fluid. In this article, a flexible thermal ground plane （FTGP） was fabricated using poly- mer materials. Kapton was employed as a casing material while micropatterned SU-8 was used to provide both a liquid wicking structure and pillars to support the casing over a vapor core. An ultra-thin TiO2 film was deposited over the SU-8 and Kapton via atomic layer deposition, which acted as both a moisture barrier and a hydrophilic coating on polymer surfaces. The assembled FTGP has a thickness of 0.30 mm, an active area of 20 mm~ 60 mm, heater area of 20 mm x 10 ram, and can operate with a heat load up to 9.54 W, with an effective thermal con- ductivity up to 541 W/（m K）.