(April 7th, 2016) New work by researchers at Stanford University and the University of Illinois at Urbana-Champaign, suggest that “metal inverse opals” could be used to cool down electronic devices as well as other thermal management applications.
Nanotechweb.org explained that “these materials are metal films that contain a periodic arrangement of interconnected spherical pores and so have a large available surface area,” which means they conduct heat and electricity well.
A team led by Kenneth Goodson at Stanford University found that heat conductivity in the metal inverse opals goes from being diffusive on the microscale to being quasi-ballistic on the nanoscale.
“The transition from diffusive to quasi-ballistic thermal conduction occurs when the size of the conduction pathway becomes comparable to the mean-free path of the thermal energy carriers (electrons in the case of metals),” team member and lead author of the study Michael Barako explained, “By tuning the pore size in these materials, we can predictably tune the size of the conduction pathway, which allows us to optimize the material’s properties for thermal management applications in the future.”
He adds that, for example, “the materials could be employed to control heat flow in electronics devices, which becomes more important as component dimensions decrease.”
They are currently exploring three different thermal applications for metal inverse opals, according to Nanotechweb.org: one “in microfluidic heat exchangers for active cooling of high-power microelectronics, in which a fluid is pumped through the inverse opal and heat exchange is accelerated by the large surface area of the material”; one “in thin-film heat pipes for passive cooling of portable electronics, such as smart phones and tablets, where capillary-driven flow through the inverse opal creates an evaporation/condensation loop”; and one “in high-rate thermal storage media, where the inverse opal is impregnated with a phase change material to form a composite thermal battery that has both a large storage capacity and can deliver/extract high rates of heat.”
The team is already “integrating metal inverse opals into functional thermal devices and measuring key performance metrics at both the material and device levels,” as well as “working on optimizing the design of their inverse opal-based thermal devices while assessing their performance, such as the rate at which they dissipate heat,” reported Nanotechweb.org.
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