Gas sensitivity of poly (3, 4-ethylene dioxythiophene) prepared by a modified LB film method

Abstract

An arachidic acid/poly (3, 4-ethylene dioxythiophene) (AA/PEDOT) multilayer Langmuir-Blodgett (LB) film was prepared by a modified LB film method. The theories were utilized to explain the effects between HCl molecule and LB film. The gas sensitivity mechanism of poly (3, 4-ethylene dioxythiophene) (PEDOT) multilayer film can be explained by the charge transfer between p system of PEDOT and oxidization HCl system. The gas sensitivity of PEDOT LB film deposited interdigital electrode to HCl was tested. The results showed that film thickness, treating temperature, deposition speed had different influence on film gas sensitivity. The AA/PEDOT film deposited device exhibited nonlinear behavior to HCl gas at lower concentration (20–60 ppm) and linear response behavior at higher gas concentration was observed. The time of the compound LB film of the AA/PEDOT responding to the 30 ppm HCl gas is about 20 seconds, which is far quicker than the time of the film to the PEDOT-PRESS film(about 80 seconds). It is not higher film press to better film. When the film press attains 45 mNs/m, the sensitivity of the AA/PEDOT film on the contrary descends.

Keywords

poly (3, 4-ethylene dioxythiophene) (PEDOT) / Langmuir-Blodgett (LB) film method / gas sensitivity / measurement

References

[1] Meng X., Hu X., Xing Y., . Research Progress on Conducting Thiophene Polymers[J]. Applied Chemical Industry, 2006, 35(7): 549-553.

[2] Hu Y., Liu Yanjun. Research Progress in Synthesis of Conducting Polythiophene and Polythiophene Derivatives[J]. Materials Review, 2006, 20(1): 64-68.

[3] Groenendaal L., Zotti G., Aubert P. H., . Eletrochemistry of Poly (3, 4-alkylenedioxythiophene) Derivatives[J]. Advanced Materials, 2003, 15(11): 855-879.

[4] Li Y., Xu J., Li Y., . Applications of Conducting Poly (3, 4-ethylenedioxythiophene)[J]. New Chemical Material, 2007, 35(3): 25-27.

[5] Kwon C. W., Campet G., Kale B. B. Structure of Thin Films of Poly (3, 4-ethylenedioxythiophene)[J]. Active and Passive Electronic Components, 2003, 26(4): 81-86.

[6] Aleman C., Armelin E., Iribarren J. I., . Structural and Electronic Properties of 3, 4-Ehtylenedisulfanylfurane and Thiophene Oligomers[J]. A Theoretical Investigation, 2005, 14(9): 151-156.

[7] Jianming O. Langmuir-Blodget Films Materials and Their Applications[M], 1999 Jinan Jinan University Press 25-28.

[8] Ke S., Liu L., Tang B., . Application of Langmuir-Blodgett Technique to Preparation of Advanced Materials[J]. Material Review, 2005, 19(1): 6-8.

[9] Carter F. L., Berg P. C., Barger W. R. Langmuir-Blodgett Test Structures for Molecular Electronics-recent Trends in Japan[ J]. Molecular Electronic Devices, 1998, 18(3): 441-463.

[10] Bi Y., Han E., Zhang Xihui. Applied Research on Langmuir-Blodgett Films Technique[J]. Chemical Industry and Engineering Progress, 2002, 21(12): 894-902.

[11] Gu C., Sun Liangyan. The Development of the LB Film Gas Sensor[J]. Transducer and Microsystem Technologies, 1992, 35(4): 8-11.

[12] Jang J., Chang M., Yoon H. Chemical Sensor Based on Highly Conductive poly (3, 4-ehtylenedioxythiophene) Nan rods[J]. Adv. Mater., 2005, 17(9): 1 616-1 620.

[13] Wang H. Y., Lando J. B. Gas-sensing Mechanism of Phthalocyanine Langmuir-Blodgett Films[J]. Langmuir, 1994, 10: 790-796.

[14] Hamaker H. C. The London-van Der Walls Attraction between Spherical Particles[J]. Physics, 1937, 4(10): 1 058-1 072.