Thin Film Construction and Characterization and Gas-Sensing Performances of a Tailored Phenylene−Thienylene Copolymer

Abstract

An alternating copolymer, poly(2,5-dioctyloxy-1,4-phenylene-alt-2,5-thienylene), has been synthesized and used in this research. The behavior of the floating film at the air-water interface has been investigated by measuring surface pressure versus area Langmuir isotherms and contemporaneously by reflection spectroscopy and Brewster angle microscopy. The floating films were transferred by the Langmuir-Schäfer (horizontal lifting) method onto various substrates. It is apparent from these analyses that the effective conjugation length is larger than those in other electroactive polymers and that a strong coplanarity and interchain association takes place above all in the floating film on the water surface and in the transferred multilayers. Such films were used as the active layers in resistive chemical gas sensor devices, thus revealing excellent sensitivity toward NO(2), reversibility, and time stability of the response.

An organic field effect transistor as a selective NOx sensor operated at room temperature

“…Examples of such devices are: amperometric sensors [12,13], semiconducting metal oxide sensors [14][15][16][17][18] and resistive sensors based on Metal-phthalocyanines [19][20][21], conjugated systems [22] as well as carbon nanotubes [23,24].…”

Electrochemical, Photophysical, and Magnetic Properties of Green Emitting bis(2,5-Hexyloxy)-Phenylene-<i>alt</i>-Thiophene Fluorescent Conducting Oligomer Addended Fullerene-Diol Dyad

“…It has been demonstrated both experimentally and theoretically that alkyl substitution in polythiophene gives rise to stronger steric hindrance and increases the torsional angles between aromatic rings (effectively reduces conjugation length) resulting spectral blue shift in absorption [32]. On the other hand, introduction of alkoxy chains at 2-and 5-positions of the phenylene rings induces spectral red shift of the same polymers [33][34][35]. Strong electron-donating property and less steric hindrance of alkoxy groups compared to alkyl substituents are considered responsible for the spectral red shift and by far, hexyloxy substituents at 2,5-position of phenylene rings have the highest effect on spectral red shift [33].…”

Advanced NOx Sensors for Mechatronic Applications

“…To date, several other NO x sensors have been proposed and examples of such devices include: semiconducting metal oxide sensors (GuO et al, 2008;Hwang et al, 2008;Wang et al, 2008;Hoa et al, 2009a;Navale et al, 2009, Qin et al, 2010Firoz et al, 2010) and resistive sensors based on metal-phthalocyanines (Oprea et al, 2007;Shu et al, 2010 ), conjugated systems (Naso et al, 2003;Nomani et al, 2010) as well as carbon nanotubes (Sayago et al, 2008;Ueda et al, 2008) and nanocomposites (Balazsi et al, 2008;Kong et al, 2008;Hoa et al, 2009b;2009c;Leghrib et al, 2010). The scientific research community is currently focusing on the development and investigation of novel materials, which are sensitive toward NO x gases as well as appropriate and well-suited for the solid-state gas sensors.…”