Gas sensing properties of a composite composed of electrospun poly(methyl methacrylate) nanofibers and in situ polymerized polyaniline
Introduction
Electrospinning (ES) was a technology developed more than a century ago [1]. It is featured with ease of fabrication of continuous nanofibers, and has received much attention worldwide because of great concerns for nanostructured materials in recent years. A large number of papers have been published on preparation of nanofibres with different morphology, such as porous nanofibers [2], [3], nanotubes [4], [5] and beaded nanofibers [6], by virtue of this simple and versatile technique. In addition, great efforts have been paid to explore the potential applications of the as-prepared nanomaterials in the fields of medicine [7], photonics [6], catalysts [8], sensors [9], etc.
Until now, much progress has been achieved in using nanomaterials prepared by ES in the biomedical field. Many biopolymers and biodegradable polymers were electrospun as non-woven membranes and used in tissue engineering biomaterials, mainly because of their interconnected, three-dimensional porous structure and relatively large surface areas, similar to the morphology of natural extra-cellular matrix [7], [10]. However, the researches on chemical and biosensors based on electrospun nanomaterials are not often reported. Wang et al. [11] used nanofibers electrospun from poly(acrylic acid)-poly(pyrene methanol) and thermally cross-linkable polyurethane latex mixture solutions as fluorescence quenching-based optical sensors, and found that they were highly responsive to metal ions (Fe3+ and Hg2+) and 2,4-dinitrotoluene due to high surface-to-volume ratios of the nanofibres. Patel et al. constructed a potential biosensor by using electrospun silica nanofibres to encapsulate horseradish peroxide enzymes [12]. Yoon et al. found that polymerization of electrospun diacetylene monomers under UV irradiation led to colorimetric sensors for volatile organic compounds [13]. Even less work is done on applying the ES technique in the development of popular and attractive gas sensors whose electrical properties change upon interaction with the analytes. Only Liu et al. [9] prepared a single polyaniline nanowire chemical sensor with a rapid response and reversible resistance change upon exposure to ammonia vapor of even very low concentration. Pinto et al. investigated the electrical responses of isolated electrospun polyaniline nanofibres to the vapors of saturated alcohols [14].
Polyaniline (PANI) is one of the most important intrinsically conducting polymers [15]. Due to the advantages of simple preparation, good chemical stability, high conductivity, etc., PANI and its composites were widely investigated as gas sensing materials for the detection of a number of chemicals, including ammonia, NO2, CO, HCl, CHCl3, N2H4, organic amine, methanol vapor, etc. [9], [14], [16], [17], [18], [19], [20], [21], [22], [23], [24]. It has been known that the morphology and structures of the sensitive materials have great effect on their sensing properties. And PANI nanofibers were reported to exhibit better sensing properties than PANI thin film in terms of sensitivity, response time, etc., which was generally proposed to relate to the high surface-to-volume ratio brought about by the nanostructure [9], [20], [21], [22], [23]. However, the researches on gas sensors based on nanostructured PANI are still quite limited.
In this paper, poly(methyl methacrylate) (PMMA) nanofibers were prepared by electrospinning technique. On the surface of PMMA fibers, polyaniline was grown by in situ polymerization to obtain a composite of coaxial PANI/PMMA nanofibers. The nanostructured composite was successfully transferred to an interdigitated gold electrode to construct a gas sensor. Its electrical responses towards TEA vapor, a typical organic amine existing in food processing and industry production, were measured at room temperature. The effects of diameters of the fibers, electrospinning time, the nature and concentration of doping acids, etc. on the gas sensitive properties of the composite have been investigated.
Section snippets
Chemicals
All the chemicals used were of analytical grade. Aniline was distilled under reduced pressure before use. PMMA (MW: 105) was purified by reprecipitation in methanol from its acetone solution. Other reagents were used as received.
Preparation of coaxial nanofibers composed of PMMA and PANI
The nanofibers of PMMA were first prepared by using electrospinning technique with a device similar to that described in Ref. [25]. Typically, a solution of PMMA in dimethylformamide (DMF) (0.18 g/mL or 0.32 g/mL) was filled in a syringe bearing a hyperdermic needle,
Characterization of PANI/PMMA coaxial nanofibers
In this paper, PANI/PMMA coaxial nanofibers were prepared by a combination of electrospining technique and in situ polymerization method. The UV–vis spectra of PMMA and the composite nanofibers are shown in Fig. 2. It can be seen clearly that no absorption peaks were observed in the spectrum of PMMA nanofibers in the studied wavelength region (350–900 nm). In contrast, two obvious absorption peaks at approximately 400 and 760 nm, were clearly observed in the spectra of the composite nanofibers.
Conclusions
Coaxial PANI/PMMA composite nanofibers were prepared by using electrospinning technique and an in situ polymerization method. The composite fibers exhibited a high sensing magnitude towards TEA vapor in the range of 20–500 ppm. In addition, the responses were linear, reversible and reproducible, suggesting their potential as a sensitive material for the detection of low concentration amine vapor. Both the diameters of nanofibers and doping acids have great effect on the sensing characteristics
Acknowledgements
The work is financially supported by the National Nature Science Foundation of China (Contract no. 50403020) and Zhejiang Province Natural Science Foundation (Grant no. M203093).
Shan-zuo Ji is a postgraduate student in the Department of Polymer Science and Engineering, Zhejiang University, China. His research interests are polymer and composite materials for gas sensors.
References (29)
- et al.
A biodegradable nanofiber scaffold by electrospinning and its potential for bone tissue engineering
Biomaterials
(2003) - et al.
Electric response of isolated electrospun polyaniline nanofibers to vapors of aliphatic alcohols
Sens. Actuators B: Chem.
(2008) - et al.
Effects of dopants on percolation behaviors and gas sensing characteristics of polyaniline film
Electrochim. Acta
(2006) - et al.
A peculiar cyclic voltammetric behavior of polyaniline in acetonitrile and its application in ammonia vapor sensor
J. Electroanal. Chem.
(2007) - et al.
Effect of NH3 gas on the electrical conductivity of polyaniline blend films
Synth. Met.
(2002) - et al.
Electrosynthesis of polypyrrole/sulfonated polyaniline composite films and their applications for ammonia gas sensing
Polymer
(2007) - et al.
Polyaniline as a new sensitive layer for gas sensors
Anal. Chim. Acta
(2003) - et al.
Electrospun poly(vinyl alcohol)/glucose oxidase biocomposite membranes for biosensor applications
React. Funct. Polym.
(2006) - et al.
Synthesis and characterization of new azobenzenesulfonic acids doped conducting polyaniline
Eur. Polym. J.
(2006) - et al.
Sensing behaviors of polypyrrole sensor under humidity condition
Sens. Actuators B: Chem.
(2005)
A review on electrospinning design and nanofibre assemblies
Nanotechnology
Nanostructured fibers via electrospinning
Adv. Mater.
Highly porous fibers by electrospinning into a cryogenic liquid
J. Am. Chem. Soc.
Direct fabrication of composite and ceramic hollow nanofibers by electrospinning
Nano Lett.
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Shan-zuo Ji is a postgraduate student in the Department of Polymer Science and Engineering, Zhejiang University, China. His research interests are polymer and composite materials for gas sensors.
Yang Li received his Ph.D. degree in polymer chemistry and physics from Zhejiang University in 2000. He has been working in Department of Polymer Science and Engineering, Zhejiang University, since 2000 and was appointed associate professor in polymer science in 2002. His research interests include polymer materials and organic/inorganic composites for chemical sensors.
Mu-jie Yang graduated from Zhongshan University, China, in 1963. She has been working in Zhejiang University since 1963. She was promoted to full professor in polymer science in 1992. Her research interests are functional polymers with optical and electrical characteristics.