Covalent Organic Frameworks with Regulated Water Adsorption Sites for Efficient Cooling of Electronics.

The excessive heat accumulation has been the greatest danger for chips to maintain the computing power. In this paper, a passive thermal management strategy for electronics cooling was developed based on the water vapor desorption process of the covalent organic frameworks (COFs). The precise regulation for the number of carbonyl group and the ratio of hydrophilicity and hydrophobicity within pore channels was achieved by water adsorption sites engineering. In particular, COF-THTA with abundant water adsorption sites exhibited highest water uptake and desorption energy, which facilitate efficient cooling of electronics. In proof-of-concept testing, COF-THTA coating (40×40 mm) provided a temperature drop of 7.5 °C in 25 minutes at a heating power of 937.5 W/m, and remained stable after 10 intermittent heat cycles. Furthermore, the equivalent enthalpy of COF-THTA coating can reach up to 1136 J/g. In real application scenarios, COF-THTA coating improved the performance of two real computing devices by 26.73 % and 22.61 %, respectively. This strategy based on COFs provides a new thinking for passive thermal management, exhibiting great potential in efficient cooling of electronics.