Brillouin-scattering determination of the acoustic properties of polymers at high pressure

Brillouin scattering is a powerful tool for probing the acoustic properties of materials. Coupled with high pressure environments, such as those accessible using diamond anvil cells, the method can reveal rich materials physics under extreme conditions, in addition to providing fundamental data for the development of equations of state. For the first time, the acoustic properties of two classes of polymers- rubbery elastomers and semi-crystalline fluoropolymers- have been measured from ambient pressure to similar to 12 GPa. From the measured acoustic properties for the elastomers, elastic constants, and moduli were determined as a function of pressure. P-V isotherms were also constructed, and fit to a range of empirical/semi-empirical isothermal equation-of-state (EOS) forms. From this analysis, the isothermal bulk modulus and its pressure derivative are reported.