Thermal conductivity of PMMA-SiO2 phononic crystals measured by AC resistance thermometry

Phononic crystals (PnCs) are a relatively new area of inquiry in both sensing and materials technology. As a future sensing material they could provide high quality factor vibrational isolation for micro-mechanical systems, or thermal mirrors for low-temperature systems. In this paper, the thermal properties of an established Phononic Crystal (PnC) are measured by AC resistance thermometry. A poly(methyl-methacrylate) (M
_w
35 kDa, Sigma) and silicon-dioxide nanoparticle superlattice was fabricated using a sequential spin-coating methodology. AC resistance thermometry was then used in order to measure the thermal conductivity of the PnC. This value was found to be 0.027 ± 0.003 W/mK. This exceptionally low thermal conductivity is believed to be caused by the nanoparticle layers in the superlattice structure rather than the layered structure of the PnC.