TY  - JOUR
A1  - Rychkov, Dmitry
A1  - Gerhard, Reimund
A1  - Kuznetsov, Alexey
A1  - Rychkov, Andrey
T1  - Influence of charge density on the trap energy spectrum in fluoroethylenepropylene copolymer films with chemically modified surfaces
JF  - IEEE transactions on dielectrics and electrical insulation
N2  - Tetrafluoroethylene-hexafluoropropylene copolymer (FEP) films were treated with titanium-tetrachloride vapor by means of molecular-layer deposition. The treatment leads to considerable improvements of the electret-charge stability on positively charged films. A slight improvement is also observed for negatively charged films. In line with our previous findings, we attribute the improvement in electret properties to the formation of deeper traps on the chemically modified polymer surfaces. Here, we investigate the influence of the charge density on electret stability of FEP films with modified surfaces. Trap-energy spectra obtained from thermally-stimulated-discharge measurements indicate that the charge stability on modified FEP films depends on how the surface traps are populated and on the availability of additional deeper traps.
KW  - Electrets
KW  - chemical modification
KW  - surface treatment
KW  - space-charge stability
KW  - charge-carrier transport
KW  - polytetrafluoroethylene (PTFE)
KW  - fluoroethylenepropylene (FEP) copolymer
Y1  - 2018
U6  - https://doi.org/10.1109/TDEI.2018.007437
SN  - 1070-9878
SN  - 1558-4135
VL  - 25
IS  - 3
SP  - 840
EP  - 844
PB  - Inst. of Electr. and Electronics Engineers
CY  - Piscataway
ER  - 
TY  - JOUR
A1  - Rychkov, Dmitry
A1  - Gerhard, Reimund
A1  - Ivanov, Vadim
A1  - Rychkov, Andrey
T1  - Enhanced electret charge stability on Polyethylene Films treated with Titanium-Tetrachloride vapor
JF  - IEEE transactions on dielectrics and electrical insulation
N2  - Low-density polyethylene (LDPE) films have been treated with titanium-tetrachloride vapor by means of the molecular-layer-deposition method. It is shown that such a treatment leads to a considerable improvement of the electret properties for both positively and negatively charged films. The temperature stability of the electret homo-charge has been increased by approximately 60 degrees C. At the same time, the temporal stability of charge is also considerably improved. Modified low-density polyethylene films show no "cross-over phenomenon" when charged to higher voltages. Thus, it is now possible to produce electrets from polyethylene films with high initial charge densities, but without a strongly reduced charge stability. The influence of a chemical treatment with titanium-tetrachloride vapor on charge injection from aluminum electrodes into polyethylene films was also investigated. It is found that the interface between an aluminum electrode and a modified LDPE surface layer has different injection properties for positive and negative charges. Electrons can be injected across the modified interface, whereas injection of holes is either very limited or non-existent.
KW  - Electrets
KW  - chemical modification
KW  - surface treatment
KW  - space-charge stability
KW  - charge-carrier transport
KW  - polyethylene
KW  - low-density polyethylene
KW  - injection
Y1  - 2012
SN  - 1070-9878
VL  - 19
IS  - 4
SP  - 1305
EP  - 1311
PB  - Inst. of Electr. and Electronics Engineers
CY  - Piscataway
ER  -