A Study on the sensitivity and selectivity properties of Polymer based gas-vapor sensors

Authors : Hüsnü CANKURTARAN, Özlem Yazıcı, Ferdane Karaman

Pages : 59-74

Doi:10.18596/jotcsa.71819

View : 12 | Download : 5

Publication Date : 2017-01-08

Article Type : Research Paper

Abstract :In this study, the water soluble poly insert ignore into journalissuearticles values(diphenylamine sulfonic acid); insert ignore into journalissuearticles values(PSDA); and the diblock copolymer of PSDA with polyinsert ignore into journalissuearticles values(ethylene glycol); insert ignore into journalissuearticles values(PEG); were used to construct the interdigitated film electrodes insert ignore into journalissuearticles values(IDEs);. Their responses against humidity and various solvent vapors were investigated by impedance measurements. Sorption and desorption behaviors of the solvents were determined by simultaneous registration of the impedance insert ignore into journalissuearticles values(Z); and the resistive insert ignore into journalissuearticles values(R, resistance); and capacitive insert ignore into journalissuearticles values(X, reactance); components of the Z under different potential bias and alternating current insert ignore into journalissuearticles values(ac); frequencies. The sensor responses were discussed considering the polar/non-polar and polarizability properties of the polymers and solvents. The effect of ac frequency and potential bias on the sensitivity and selectivity of the sensors were discussed.  It was found that the solvent polarity is the primary effect on the electrical conductance and capacitance of both PSDA homo polymer and PSDA-b-PEG block copolymer. The results supported that the dipolarity-polarizability properties of solvents have also a critical role on sensor response at low ac frequencies. The more polarizable solvents gave higher sensor responses at lower ac frequencies. The equilibrium response of the PSDA based sensor was correlated with the dielectric constant of the solvents. The values of Z and R of PSDA film under saturated solvent vapors at 1 kHz ac frequency were linearly correlated insert ignore into journalissuearticles values(R 2 was 0.955, 0.993 and 0.957 for Z, R and X, respectively, in semi-logarithmic scale); with the values of the dielectric constants of the solvents, except water. A similar correlation insert ignore into journalissuearticles values(R 2 = 0.996); was obtained by using the R values of the PSDA film at 100 kHz ac frequency. In the case of PSDA-b-PEG polymer film, it was also possible to establish an almost linear correlation insert ignore into journalissuearticles values(R 2 =0.943); between the R at 100 kHz ac frequency and the values of the dielectric constants of the solvents, except acetone and water. Consequently, it was found that the applied ac frequency was distinctive on both the sensitivity and selectivity of the studied sensor. 
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