(618a) Metal Organic Framework Materials for Sound Attenuation Applications

Nune, S. K., Pacific Northwest National Laboratory
Miller, Q., Pacific Northwest National Laboratory
Schaef, H. T., Pacific Northwest National Laboratory
Denslow, K., Pacific Northwest National Laboratory
Martin, P., Pacific Northwest National Laboratory
McGrail, B. P., Pacific Northwest National Laboratory
Metal Organic Frameworks (MOFs), a novel class of crystalline materials are most studied materials of 21st century. In MOFs, metal-clusters called secondary building units (SBUs) are connected to organic linkers to form highly connected and non-interpenetrating networks. Variability in metal clusters and judicious choice of organic likers offer MOFs with the possibility of topologically diverse structures with extremely high surface area, tunable pore size and flexibility. Engineered MOFs with flexibility and porosity have been used in many applications including gas storage, catalysis, sensing and energy storage applications. To the best of our knowledge there is no prior work on their use in sound attenuation applications. We recently examined acoustic properties of commonly used MOFs using impedance tube at low frequency (100-1250 Hz). We demonstrated that MOFs are absorptive acoustic metamaterials and has superior sound transmission loss (STL) than predicted by mass-law predictions. Sound dampening by MOFs may be due to sound dissipation and absorption facilitated by multiple internal reflections within the microporous framework structure. The acoustic absorption relies heavily on porous structure with interconnected paths with increased reflections. We will present our recent results on low frequency sound attenuation of MOFs and their potential use in contrast imaging applications.