Effect of end group of amorphous perfluoro-polymer electrets on electron trapping

Figures & data

Figure 1. Schematic chemical structure of CYTOP polymers.

Figure 2. Infrared absorption spectra of CTL-S, CTL-A and CTL-M.

Figure 3. TSD spectra of CYTOP polymers.

Table 1. Surface charge density of negatively charged, 15 μm-thick amorphous fluropolymers [11,12].

	End group	Surface charge density after 200 h (mC/m^2)
CTL-M	Amidosyl	−1.3
CTL-A	COOH	−0.87
PTFE	–	−0.84
CTL-S	CF3	−0.37

Figure 4. (a) Principle of the inverse photoelectron spectroscopy (LEIPS), (b) Schematic of the LEIPS measurement setup.

Figure 5. LEIPS results: (a) Intensity of emitted light from CTL-S with 0.15 μA of sample current, (b) Intensity of emitted light from CTL-S with 0.70 μA of sample current, (c) Thickness dependence of LEIPS onset energy for CTL-S, (d) Intensity of emitted light from CTL-A with 0.15 μA of sample current, (e) Intensity of emitted light from CTL-A with 0.70 μA of sample current, (f) Thickness dependence of LEIPS onset energy for CTL-A.

Figure 6. Influence of the external electrostatic field on electron affinity.

Figure 7. Ground-state structures of (a) PE, (b) PTFE, (c) PTFE, (d) CTL-S, (e) CTL-A, (f) CTL-M.

Note: Red and blue meshes represents distribution of the trapped electron.

Figure 8. Strong electron-attracting characteristics of CTL-M end group.

Note: The trapped electron stays near amide bond of CTL-M, even structural conformation is transformed.

Figure 9. Calculated orbital energy level of PTFE with different number of carbons.

Figure 10. Visualized distribution of the trapped electron in CYTOP monomers.

Figure 11. Calculated orbital energy level of polymer electrets.

Note: The bars with arrows represent energy of orbital where the electron is trapped.

Table 2. TSD peak temperature of polymer electrets.

	PE	ETFE	PTFE	CTL-S	CTL-A	CTL-M
	[42,43]	[44]	[12,43,45]	[11,12]	[11,12]	[11]
Sample thickness (μm)	1, 10, 160	50	15, 25	15	15	15
TSD peak temperature (°C)	35–70	120–160	138–230	135	148	170

Shen L , Xia Z , Ji Z . 2005. Charge storage and its dynamic characteristic of ETFE film electrets. IEEE 12th International Symposium on Electrets (ISE12). p. 224–226.10.1109/ISE.2005.1612361

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Sakane Y , Suzuki Y , Kasagi N . The development of a high-performance perfluorinated polymer electret and its application to micro power generation. J Micromech Microeng. 2008;18:104011.10.1088/0960-1317/18/10/104011

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