Photoacoustic Permeability Detection to Both Water Vapor and Artificial Tears of PVDF Transfer Membranes as a Piezoelectric and Ferroelectric Polymer

Photoacoustic configuration studies were performed to measure the water vapor permeability of the polymeric PVDF transfer membranes with a pore size of 0.45 µm and a thickness of 117 and 119 µm, taking advantage of the characteristic that the polyvinylidene difluoride (PVDF), once polarized by the corona poling, creates a piezoelectric polymer. Polymeric membrane measured polarized as a piezoelectric polymer and an unpolarized ferroelectric polymer. Polarized and non-polarized PVDF membranes were developed for the two experimental photoacoustic detection of permeability tests; the first one was used to measure the humidity of bi-distilled water, and the second one was characterized with artificial tears. The obtained results show that PVDF membrane has different permeability coefficient for water and artificial tears, and at the same time, pores in the tested membranes change sizes depending on the liquid used. The results of the permeability and pore size of the PVDF membranes provide insight into vapor transport mechanisms that may inform the future development of humidity sensors.