Dynamic Nanofi n Heat Sinks

The limitation of hot spot cooling in microchips represents an important hurdle for the electronics industry to overcome with coolers yet to exceed the effi ciencies required. Nanotechnology-enabled heat sinks that can be magnetophoretically formed onto the hot spots within a microfl uidic environment are presented. CrO 2 nanoparticles, which are dynamically chained and docked onto the hot spots, establish tuneable high-aspect-ratio nanofi ns for the heat exchange between these hot spots and the liquid coolant. These nanofi ns can also be grown and released on demand, absorbing and releasing the heat from the hot spots into the microfl uidic system. It is shown that both high aspect ratio and fl exibility of the fi ns have a dramatic effect on increasing the heat sinking effi ciency. The system has the potential to offer a practical cooling solution for future electronics.