Characterization of open-cellular polymeric foams using micro-computed tomography

Utilization of Polyvinylidene fluoride (PVDF) open-cellular foam allows for the creation of high-efficiency Triboelectric nanogenerators (TENG). The micro-structure of TENG devices can be problematic to characterize accurately using conventional methods like scanning electron microscope (SEM). This work aims to provide a methodology in which representative 3D measurements can be made on open-cellular PVDF foams. Open-cell PVDF foams were produced through a salt-leeching procedure. Analysis of the PVDF foams was done by imaging the sample through a desktop micro-computed tomography (μ-CT) machine to allow for a full 3D dataset to be obtained. Foams were produced with salt sizes of 250–500 μm, 106–250 μm, 53–106 μm, and <53 μm to explore the capabilities of the segmentation procedure at identifying the microstructure of the foam. Images were segmented and analyzed to calculate the porosity, sample volume, pore volume and surface area. Results from μ-CT analysis were compared to that from a SEM, which is currently the most widely used method for assessing open foam PVDF structures. Results from the μ-CT when quantifying pore dimensions proved to be much more representative than SEM due to its ability to capture the entire volume of the foam rather than a single plane. These techniques can be used as the baseline for further verification and improvement the manufacturing of PVDF foam structures.