A.B. Baumann, P.A. Beaucage, R. Vallery, D. Gidley, R.C. Nieuwendaal, C.R. Snyder, J. Ilavsky, C.M. Stafford, C.L. Soles
National Institute of Standards and Technology,
United States
Keywords: polymer, MOF, composites, PEO, characterization
Summary:
Metal-organic frameworks (MOFs) are gaining popularity in a variety of applications in industrial separations, biomedical devices, and chemical or energy storage technologies. However, the powdery characteristics of MOFs limit their practical implementation in device-scale architectures, necessitating their inclusion in polymer matrices for widespread utilization. Traditional methods for characterization of MOF/polymer composites tend to be qualitative in nature. Herein, we describe techniques designed to quantitatively measure the interactions between MOF and polymer components and their resulting effects on composite structure. Specifically, we use a combination of NMR, DSC, X-ray scattering, and PALS to provide a holistic picture of MOF/polymer proximity, amorphous polymer content, degree of polymer infiltration, and residual porosity in MOF/PEO composite films as a function of MOF loading. Our measurement strategy provides a foundation as we seek to develop additional analytical tools capable of describing the complex chemical and physical attributes of MOF-polymer composites across a multitude of length scales and compositions. In addition to guiding characterization efforts in the field, we envision these results will be useful in designing high-throughput classification schemes that will enable more efficient design of composites with targeted properties.