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Table 1. Solving and electrophoresis of dyes in organic solution
No. Dyes
P A +A Alcohol PCE+A Glycol ether
X + A PCE+
PIBI
1 Acid red ¥ୄ— ¥ୄ— ¥ୄ—
2 Acid black 1 ¥ୄ— ¥ୄ—
3 Acid black210 ¥ୄ— ¥ୄ—
4 Acid black234 ¥ୄ— ¥ୄ—
5 Metal complex blue 06 ¥ୄ— ¥ୄ— ¥ ୄ— ¥ୄ— ¥ୄ—
6 Metal complexes 04 ¥ୄ— ¥ୄ— ¥ ୄ— ¥ୄ— ¥ୄ—
7 Metal complex yellow 20 ¥ୄ— ¥ୄ— ¥ ୄ— ¥ୄ—
8 Metal complex black 20 ¥ୄ— ¥ୄ— ¥ ୄ—
9 Metal complex red 06 ¥ୄ— ¥ୄ— ¥ ୄ—
10 Metal complex brone 02 ¥ୄ— ¥ ୄ— ¥ ୄ—
11 GN-20 ¥ୄ— ¥ ୄ— ¥ୄ— ¥ୄ— ¥ ୄ—
12 BL-03 ¥ୄ— ¥ୄ— ¥ୄ+ ¥ୄ— ¥ୄ— ¥ ୄ—
13 Metal complex Purple 08 ¥ୄ— ¥ୄ+ ¥ୄ+ ¥ ୄ—
14 Metal complex brone BN-05 ¥
15 Metal complex orange 09 ¥
(A+A): Aniline+Alcohol; (PCE+A): Tetrachloroethene+Aniline; (X+A): Xylene+Aniline; P: Pyridine;
¥, electrophoresis OK; (-) dye charged negative; (+) dye charged positive;
PIBI: succinimide (trade name: OLOA1200, product of Chevron Corp.)
3.2 Displaying of prototype dye ink E-paper
The results (Fig.2) indicated that the absorption peak at about 370nm, which was attributed to the absorption of azo compounds, decreased gradually with increasing driving voltage. The result shows you that the Red 04 is reducing with the electrochemical reaction during electrophoresis with ordinary ITO electrode [6].
When the electrode was covered by PI, the Abs will not decrease during electrophoresis.
3 0 0 4 0 0 5 0 0 6 0 0 7 0 0 8 0 0
-0 .1 5 -0 .1 0 -0 .0 5 0 .0 0 0 .0 5 0 .1 0
abs
w a v e le n g th M e ta l C o m p le x e d 0 4
V = 0 V = 1 , I= 0 .0 4 V = 2 , I= 0 .3 9 V = 3 , I= 0 .6 5 V = 4 , I= 0 .9 6
Fig.1 Picture of dye ink prototype E-paper Fig.2 UV-Vis curves of dye ink under driving 3.3 The stability of dyes’ structure under voltage driving
Fig.3 shows the cyclic volt-ampere curve (-2V to 2V) of Red 04 in ethanol (2.2×10-3mol/l).
It is considered that the redox voltage of Red 04 metal complex dye is about 1 V, and during the electrophoresis pr ocess of Red 04 in ethanol, the dye was changed into other products.
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Fig.3 Cyclic volt-AM curves of Red 04 Fig. 4 IR spectra of Red04 before and after electrophoresis
NO2
OH
N N C
C N
N C OH
M+
Structure of Red 04
It was found from the Fig.4 that new peaks at 1377.1, 1269.4 and 1456 cm-1 were generated, while peaks at 1369.
9, 1301.9, 1261.1 cm-1 disappeared after electrophoresis. It could be concluded that the main electrochemical prod ucts in this reaction were oxidized azobenzene, which reduced azo benzene when azo dye was involved in electro chemical reaction. It was proved that the decreases of UV-Vis abs in Figure 2 was caused by the decomposition of azo structure and provided the direct evidence that electrochemical reaction took place during the electrophoresis process. As revealed by the data listed in table 1[7], it could be concluded that the main electrochemical products i n this reaction were oxidized azobenzene, not hydrogenised azobenzene which was supposed the main product, i.e ., reduced azo benzene when azo dye was involved in electrochemical reaction [8].
Table 1. IR frequency some groups Wavenumber-1 /cm-1 Groups 1468-1360ୄvs. extend vibration
1494.7ୄvs.Obey extend vibration
Ar-N=N- PV1558.4ୄvs.Sym extend vibration
1332.7(s) Asym extend vibration
Ar-NO2 1417.6(vs.) anti phenyl -C=N extension
1261-1377 extension NĺO
Ar-N=N(ĺO)
3.4 Response time of Red 04 dye ink prototype E-paper display
Figure 5 shows that the higher the concentration of Red 04 ink, the bigger effect of driving on dye degradation rea ction. Figure 6 gives a best concentration of Red 04 dye ink is under 0.002mol/L.
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Fig.5 Response time and concentration of Red 04 Fig.6 Response time and driving of Red 04
4. Summary
4.1 Some dyes such as Red 04 was found can be used in electrophoresis display and the prototype E-paper was produced.
4.2 Dye organic solution electronic ink is worth to investigate deeply in E-paper. For dye ink is much stable than pigment ink, although the responding speed is slower.
4.3 The structure damage of dye during electrophoresis could be avoided by PI protected ITO Driving electrode.
Acknowledgements
The study was supported by Funding of Beijing Municipal Education Committee PHR (IHLB).
5. References 1. Lu-hai LI, Information Recording Materials Vol3p:58(2003) 2. Barrett Comiskey, J, D, Albert, Nature , Vol394(16) p:253 (1998)
3.Lu-hai LI; Shun-fen ZHANG; Jin-zong YANG; Jing ZOU.Journal of Functional Materials, Vol 35(4) p407-409(2004)
4. Zhao-Lin ZHANG, Yu-Zhen ZHANG, Metal Complex Dyes, Press of Chemistry (China), 1986
5. Lu-hai LI, Ming WANG, ICISH’ 2008, Proceeding, p61, Zhanjiang City, Guangdong Province, P. R. China 6. Lu-hai LI, Ming WANG, Shu-nan QIAO, Journal of functional materials, Vol.38P7 (2007)
7. John A. Dean, Analytical Chemistry Handbook, Science Press, Beijing.2003 P6.30 8. Wen-rong HU, Hai-yan PEI, Chinese Science Bulletin, 2001.12:2049-2052
