Annealing for the improvement of the capabilities of parylene C as electret

作者：Kachroudi, A^*; Lagomarsini, C; Mareau, V H; Sylvestre, A

来源：Journal of Applied Polymer Science, 2019, 136(1): 46908.

DOI：10.1002/app.46908

• corona discharge
• electret
• parylene C
• semi-crystalline polymer
• surface potential decay
• thermal stability

Parylene C is a polymer elaborated by chemical vapor deposition and is particularly useful for the coating of deformed structures. New-generation soft energy harvesting electrostatic generators can be of complex shape. These generators need electret material in order for them to function. It could thus be interesting to incorporate parylene C in this device. However, this polymer suffers from bad retention of trapped charges after corona discharge and a poor thermal stability of these charges. In this work, parylene C polymers were subjected to specific annealing before corona charging. This induces strong changes in the crystallinity of the material. Atomic force microscopy and X-ray diffraction quantified the crystalline nature of parylene C following the annealing temperature. Surface potential decay of corona-charged parylene C demonstrated that annealing to about 150 degrees C is beneficial for the trapping of charges for a long time (analysis over 12 days). At the same time, thermal stability of the electret parylene C is achieved up to 100 degrees C. Spherulites with a specific area close to the surface of the polymer could explain such performances due to their influence on the distribution of traps. Dielectric analysis does not confirm that the decay of surface charges is correlated to the dynamics of polymer chains, although the moving of chains probably influences the flowing of these charges. In sum, annealed parylene C appears to be a new interesting candidate for electret-based electrostatic generators.

• 出版日期2019-1-5
• 单位中国地震局