Piezoelectric poly-g-benzyl- L -glutamate polymethyl methacrylate composite disks fabricated using molds

Poly-g-benzyl-L-glutamety Polymethyl methacrylate (PBLG-PMMA) composite polymer, a new piezoelectric transduction material, was invented by Yu et al. In this study a method is developed to fabricate a disk using detachable molding. Unlike film-type piezoelectric polymers such as the polyvinylidenefluoride (PVDF), this new material can be used to form a body of various shapes and sizes such as conventional piezoelectric ceramics. The piezoelectric characteristics mainly come from the state of alignment of polygamma-benzyl alpha, L-glutamate molecules (PBLG), which have large electric dipole moment. The PBLG can be melted with methyl methacrylate by heating, and mixture with applying electric field can be polymerized as a piezoelectric PBLG-PMMA composite in the mold. The fabricated specimens have the dimensions of 20 mm in diameter and 3 mm in height. The piezoelectric coefficient (d33) depends on the concentration of PBLG. Measured values were 0.45 and 1.9 pC/N with concentrations of 10 and 30 wt %, respectively. Even though these values are lower than PVDF, PBLG-PMMA could be applied as a transduction material in various shapes of acoustic transducers because the results suggest that increasing the intensity of electric field and the PBLG concentration may improve the piezoelectricity. Moreover, it is also a great potential to consider new matrix materials instead of PMMA. [Work supported by Grant No. ADD-UD080004DD.]