Effect of Ultraviolet Activation on Sub-ppm NO Sensing Dynamics of Poly(3-hexylthiophene)-Bearing Graft Copolymers.

Nitrogen dioxide (NO) sensors utilising graft copolymers bearing poly(3-hexylthiophene) chains have been developed and investigated in terms of their operation parameters using different carrier gases (N or air) and in either dark conditions or with ultraviolet (UV) irradiation. Interestingly, sensor performance improved upon transition from N to air, with the inverse being true for most NO sensors. UV irradiation both improved sensor dynamics and stabilised the sensor electrical baseline, allowing sensors based on SilPEG to fulfil the requirements of sensing solutions used in industry (below 10% baseline drift after sensors reach saturation) and making them promising candidates for further development and applications.

Investigation of the Effects of Non-Conjugated Co-Grafts on the Spectroelectrochemical and Photovoltaic Properties of Novel Conjugated Graft Copolymers Based on Poly(3-hexylthiophene).

A new type of polysiloxane copolymers, with conjugated⁻regioregular poly(3-hexylthiophene) (P3HT) and non-conjugated-poly(ethylene glycol) (PEG)-grafts have been synthesised, and their properties have been studied alongside those of the parent conjugated polymer (P3HT). Spectroelectrochemical and conductometric analyses revealed an early rise of the conductance of the polymers. Once spectral changes begin taking place, the conductance is stable, implying a loss of mobility of charge carriers, even though standard doping/dedoping patterns are observed.

Poly(3-hexylthiophene) Grafting and Molecular Dilution: Study of a Class of Conjugated Graft Copolymers.

A type of graft copolymer based on polysiloxane and regioregular poly(3-hexylthiophene) (P3HT) has been synthesised and its properties have been studied alongside those of its parent conjugated polymer-regioregular P3HT. Electrochemical analysis has revealed more significant changes in conformation of the copolymer film than was observed for P3HT. UV-Vis-NIR spectroelectrochemical investigation provided evidence of improved doping reversibility of the copolymer, despite its marginally increased band gap, as also confirmed by electroconductometric analysis.

A Study on the Impact of Poly(3-hexylthiophene) Chain Length and Other Applied Side-Chains on the NO₂ Sensing Properties of Conducting Graft Copolymers.

The detection and concentration measurements of low concentrations of nitrogen dioxide (NO₂) are important because of its negative effects on human health and its application in many fields of industry and safety systems. In our approach, conducting graft copolymers based on the poly(3-hexylthiophene) (P3HT) conducting polymer and other side-chains, polyethylene glycol (PEG) and dodec-1-en, grafted on a poly(methylhydrosiloxane) backbone, were investigated. The grafts containing PEG (PEGSil) and dodec-1-en (DodecSil) in two variants, namely, fractions with shorter (hexane fraction -H) and longer (chloroform fraction -CH) side-chains of P3HT, were tested as receptor structures in NO₂ gas sensors.

Spectroelectrochemistry of poly(3-hexylthiophenes) in solution.

Abstract: The first comprehensive spectroelectrochemical account of the behaviour of regioregular (RR-P3HT) and statistical (ST-P3HT) poly(3-hexylthiophenes) in solution is presented, in contrast to the many reports dealing with P3HT films merely deposited from solution. The conducted experiments revealed that the two types of P3HTs behave in sharply different ways upon the application of electrochemical stimuli: ST-P3HT readily precipitates at mildly oxidative potentials, while the precipitation of the RR-P3HT takes place to a much lesser extent, even at higher potentials. The two polymers, studied via UV-Vis-NIR-EPR spectroelectrochemistry, exhibited properties mostly in line with earlier reports.