Gas and humidity response of iron oxide—Polypyrrole nanocomposites

Tandon, R. P.; Tripathy, Malay Ranjan; Arora, Aman; Hotchandani, Surat

doi:10.1016/j.snb.2005.07.022

Cited by 116 publications

(46 citation statements)

References 20 publications

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“…[8][9][10] There are also some literatures reporting the great improvement achieved in sensitivity of ammonia gas vapors using PPy/oxide-iron composite films. [11][12][13] Titanium dioxide (TiO 2 ) is an n-type semiconductor, which has been extensively used for detecting H 2 , NH 3 , and SO 2 gases. 14,15 However, the sensors based on TiO 2 require an elevated operation temperature, which may cause long-term instability.…”

Section: Introductionmentioning

confidence: 99%

Examining the use of TiO₂ to enhance the NH₃ sensitivity of polypyrrole films

Yan

Xing

2010

J of Applied Polymer Sci

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Polypyrrole/Titanium dioxide (PPy/TiO 2 ) composite thin films were prepared by polymerizing the monomer pyrrole in aqueous solution containing a certain amount of TiO 2 particles at room temperature, and their response to ammonia (NH 3 ) gas was examined systematically. Compared with the pristine PPy film, which reached the saturation at the concentration of NH 3 beyond 200 ppm, the composite films showed more stable response and higher sensitivity. Furthermore, the PPy/TiO 2 composite thin films exhibited a low detection limit of 2 ppm. The film thickness, which had a strong influence on the film sensitivity to NH 3 , could be controlled by varying the polymerization time. The sensitivity to NH 3 gas of the samples with different content of TiO 2 and different molar ratio of PPy/TiO 2 /oxidant was studied.

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Section: Introductionmentioning

confidence: 99%

Examining the use of TiO₂ to enhance the NH₃ sensitivity of polypyrrole films

Yan

Xing

2010

J of Applied Polymer Sci

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“…To enhance the operating of these sensors, composites of CP and metal oxides [46,[128][129][130][131][132][133] and nanoparticles and carbon nanotubes [134][135][136] have been proposed and tested.…”

Section: Affinity To Gases and Vaporsmentioning

confidence: 99%

Conducting Polymers as Artificial Receptors in Chemical Sensors

Lange

Roznyatovskaya

Hao

et al. 2010

Artificial Receptors for Chemical Sensors

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Conducting polymers are commonly used materials in chemical and biological sensors. These materials possess receptor as well as transducer functions [1]. Typical examples of conducting polymers (CPs) include polythiophenes, polypyrroles, polyanilines, and polyphenylenes. Such polymers show some intrinsic receptor properties towards analytes that can react/interact with the polymer, like, for example, redox active or acidic/basic gases. Oxidation/reduction and in some cases protonation/ deprotonation introduces/removes charge carriers in the conjugated backbone, whereas conformational changes alter the planarity of the conjugated backbone, which leads to changes in the mobility of the charge carriers. Figure 12.1 demonstrates the example of PANI (polyaniline), showing the influence of redox potential and pH on the interconversion between the different forms of PANI.These changes can be detected by in situ resistance, UV-vis, IR, or fluorescence measurements. Direct interactions with the p-system often produce very large signal changes; however, they are quite non-specific. A possible way to introduce some selectivity in these polymers is to modify their conjugated backbone with receptors.Usually, receptors can be introduced into a polymer backbone either after polymerization or directly to monomer, which is polymerized or copolymerized. The synthetic availability and the ability to polymerize the monomer under certain conditions are the most common limitations in the choice of a derivative with receptor group. Some classes of these receptors are discussed in Section 12.4. Doping of CPs by counter ions bearing the required receptor [2-8], the inclusion of ionophores into the polymer matrix [9], and the chemical linkage of ligands or receptor units to the polymer backbone [10] are also applied to enhance the selectivity and sensitivity of CPs. Receptors attached to the p-system via some short side chain can communicate with the p-system of the polymer by, for example, electron donating/withdrawing, electrostatic interactions or by inducing conformational changes upon analyte binding. As there is no direct interaction with the polymer backbone, the signal change may be smaller, but also much more specific. Artificial Receptors for Chemical Sensors. Edited

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“…Nonetheless, iron oxide nanoparticles have been utilized in a diverse array of sensors, primarily as humidity sensors [186][187][188]. Although these are slightly beyond the scope of traditional electroanalytical sensors, they deserve a mention.…”

Section: Iron Nanoparticlesmentioning

confidence: 99%