@article{RychkovRychkovEfimovetal.2013,
  author    = {Rychkov, Dmitry and Rychkov, A. and Efimov, N. and Malygin, A. and Gerhard, Reimund},
  title     = {Higher stabilities of positive and negative charge on tetrafluoroethylene-hexafluoropropylene copolymer (FEP) electrets treated with titanium-tetrachloride vapor},
  series = {Applied physics : A, Materials science \& processing},
  volume    = {112},
  journal   = {Applied physics : A, Materials science \& processing},
  number    = {2},
  publisher = {Springer},
  address   = {New York},
  issn      = {0947-8396},
  doi       = {10.1007/s00339-013-7821-1},
  pages     = {283 -- 287},
  year      = {2013},
  abstract  = {Tetrafluoroethylene-hexafluoropropylene copolymer (FEP) films were treated with titanium-tetrachloride vapor in a molecular-layer deposition process. As a result of the surface treatment, significant improvements of the thermal and temporal charge stability were observed. Charge-decay measurements revealed enhancements of the half-value temperatures and the relaxation times of positively charged FEP electrets by at least 120 A degrees C and two orders of magnitude, respectively. Beyond previous publications on fluoropolymer electrets with surface modification, we here report enhanced charge stabilities of the FEP films charged in negative as well as in positive corona discharges. Even though the improvement for negatively charged FEP films is moderate (half-value temperature about 20 A degrees C higher), our experiments show that the asymmetry in positive and negative charge stability that is typical for FEP electrets can be overcome by means of chemical surface treatments. The results are discussed in the context of the formation of modified surface layers with enhanced charge-trapping properties.},
  language  = {en}
}