What could possibly beat it? Many scientists are exploring the use of carbon nanotubes as thermal interface materials. These have been a hot topic for the past couple years, with many graduate students exploring their potential.
Unfortunately, that is all they are today. They are a
Why can't the nanoparticles just be squished together, lowering the thermal resistance, but still capturing the high conductivity of the bulk material? The resistance between the nanoparticles is high enough, even in a silicone suspension, to increase the resistance much higher than a metal TIM.
As far as I am aware, metal thermal interface materials are the highest performing, viable solution available today. If anyone can prove otherwise, please let me know! I look forward to this discussion!
Image courtesy of http://www.epa.gov/epahome/enviroeye/images/nanotubes.jpg