Effect of humidity in charge formation and transport in LDPE

Aragoneses, Andrés; Tamayo, I.; Lebrato, A.; Cañadas, J. C.; Diego, J. A. de; Arencón, D.; Belana, J.

doi:10.1016/j.elstat.2013.03.003

Cited by 9 publications

(12 citation statements)

References 27 publications

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“…In the same temperature range of the conductivity change, the loss feature undergoes a non-monotonous frequency shift and a significant decrease in strength (by a factor of three). The observed decrease of σ dc upon desorption of water is reminiscent of the behavior of many insulating and semiconducting porous inorganic materials [2][3][4][5] in which a conductivity enhancement is observed after exposure to humidity. It may be gathered from panel c that the conductivity variation is approximately of four orders of magnitude, a dramatic effect which is in line with reported conductivity enhancements in inorganic systems.…”

Section: B1 Effect Of the Surface Hydrationmentioning

confidence: 90%

“…It may be gathered from panel c that the conductivity variation is approximately of four orders of magnitude, a dramatic effect which is in line with reported conductivity enhancements in inorganic systems. [2][3][4][5] The recovery of the conductivity value of the pristine material at relatively low temperatures and the absence of the other changes visible in the hydrate (Figure 2) together indicate that, in the short exposure to air prior to measurement, the material did not have time to form a stable hydrate phase containing structural water. We thus conclude that air exposure led to condensation of (loosely bound) hydration water onto the surface of pure C 60 (ONa) 24 grains.…”

Section: B1 Effect Of the Surface Hydrationmentioning

confidence: 99%

“…This suggests that only the hydrated forms of the derivatives C 60 (OX) 24 (X = H, Na), and not the pure materials, behave as proton conductors. Moreover, our findings help shed light on two well-known and yet controversial water-induced conductivity effects, namely the surface conductivity enhancement and the worsening of electrical insulation in a humid environment, [2][3][4][5][6] and the conductivity changes associated with structural dehydration. …”

Section: Introductionmentioning

confidence: 99%

“…1 Exposure to humid air and the ensuing condensation of water vapor onto a material's surface introduces new mechanisms for charge generation and transport, which in semiconducting and insulating materials may result in an increase of the overall conductivity by several orders of magnitude. [2][3][4][5][6] This well-known effect is exploited in many kinds of humidity sensors based on inorganic materials such as ceramics or organic materials such as polymers. 7,8 The presence of water can also have an important effect on the dielectric response of materials, e.g.…”

Section: Introductionmentioning

confidence: 99%

“…9 The dc conductivity of organic and inhomogeneous inorganic semiconductors in their pure form is quite low, so that the introduction of new charge carriers or conduction paths upon adsorption of water leads in many instances to an increase in the material's conductivity, for some cases even by several orders of magnitude. [2][3][4][5][6] The exact mechanism underlying such effect both in organic and inorganic systems is a matter of debate, 2 and it may not be unique nor the same for all materials.…”

Section: Introductionmentioning

confidence: 99%

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Water-Triggered Conduction Mediated by Proton Exchange in a Hygroscopic Fulleride and Its Hydrate

et al. 2014

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Impedance spectroscopy is employed to probe the impact of water on the dc conductivity and ac dielectric response of the polycrystalline C 60 (ONa) 24 fulleride, both in its bulk-hydrate form, stable only below 370 K, and in the pure form, obtained by heating to high temperature. Exposure of the pure material to ambient air results in the condensation of water vapor on the crystallites' surface, which in turn leads to an enhancement of the room-temperature conductivity by four orders of magnitude due to charge transport through the hydration layer. Electrical conduction in the hydrate between 320 and 380 K is dominated by a non-equilibrium contribution associated with the structural water, which leads to a value of the dc conductivity that is higher than that of the pure material by almost two decades at 360 K. Both conductivity enhancements are most likely due to a proton exchange mechanism. All impedance spectra exhibit, in the radiofrequency range, a dielectric loss feature related to the accumulation of free charges at grain boundaries, whose strength is strongly affected by the presence of hydration water.

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Section: B1 Effect Of the Surface Hydrationmentioning

confidence: 90%

Section: B1 Effect Of the Surface Hydrationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Water-Triggered Conduction Mediated by Proton Exchange in a Hygroscopic Fulleride and Its Hydrate

et al. 2014

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Degradation of polyimide under exposure to 90 keV electrons

Plis¹,

Engelhart

Barton

et al. 2017

Physica Status Solidi (b)

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Interaction of high energy electrons with spacecraft materials, such as polyimide (PI, Kapton 1 ), is known to cause their physical degradation. In this paper, we investigated chemical and optical changes in Kapton 1 during and after irradiation with high energy (90 keV) electrons. Several complimentary characterization techniques were utilized to qualify and quantify radiation induced property changes in the material, including directional-hemispherical reflectance (DHR) coupled with Fourier transform infrared (FTIR) spectroscopy, electron paramagnetic resonance (EPR), and the surface potential decay method. It was found that the conductivity of radiation-damaged PI is significantly increased compared to that of the pristine material. This change is attributed to the creation of radicals during irradiation, which could play a critical role in the transport of electrons through the bulk of the damaged material. Excessive radicals are likely originating from a radiation-induced breakage of phenyl rings and/or ether bridges forming a metastable carbonyl.

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