Pimpa Hormnirun

Electrical Conductivity Response of Poly(Phenylene-vinylene)/Zeolite Composites Exposed to Ammonium Nitrate

Poly(p-phenylenevinylene) (PPV) was chemically synthesized via the polymerization of p-xylene-bis(tetrahydrothiophenium chloride) monomer and doped with H2SO4. To improve the electrical conductivity sensitivity of the conductive polymer, Zeolites Y (Si/Al = 5.1, 30, 60, 80) were added into the conductive polymer matrix. All composite samples show definite positive responses towards NH4NO3. The electrical conductivity sensitivities of the composite sensors increase linearly with increasing Si/Al ratio: with values of 0.201, 1.37, 2.80 and 3.18, respectively. The interactions between NH4NO3 molecules and the PPV/zeolite composites with respect to the electrical conductivity sensitivity were investigated through the infrared spectroscopy.

Sensitive and Selective Responses of Poly(Para-Phenylene Vinylene)/Zeolite Y-Based Sensors Toward Ketone Vapors

Poly (p-phenylene vinylene) doped with H2SO4 is mixed into zeolite Y matriced to improve the electrical conductivity responses toward ketone vapors. The effect of cation type, cation concentration, and ketone vapor type on the electrical conductivity response toward ketone vapors of dPPV_zeolite Y composites is investigated. The sensitivities of the composites increase linearly with increasing surface area and decreasing cationic radius of the cation in zeolite Y. The highest sensitivity is obtained with the dPPV_[90] Y when exposed to acetone, whereas in MIBK shows the lowest sensitivity The interactions between the ketone molecules and the composites are investigated though the FTIR.

Ammonia sensing and electrical properties based on composite of poly(3-thiopheneacetic acid) and zeolite Y

Abstract Poly(3-thiopheneacetic acid) (Pth) was synthesised and doped with perchloric acid. The electrical conductivity sensitivity towards ammonia is further improved by introducing Y zeolites into the doped Pth matrix. For the effect of zeolite content, the composite with 10% (v/v) of the Y zeolite gives the highest electrical conductivity sensitivity (Δσ/σN2) values when exposed to NH3. The electrical conductivity sensitivity (Δσ/σN2) monotonically increases with increasing Si/Al ratio. The highest electrical conductivity sensitivity of all composites investigated is obtained with the doped Pth/zeolite Y (Si/Al = 80) at the value of (7·46±3·56)×102. The interaction between NH3 and the doped Pth is shown to be reversible based on the Fourier transform infrared spectra.

Synthesis of Poly (2,5-dimethoxyaniline) and Electrochromic Properties

Poly(2,5-dimethoxyaniline) (PDMA) was synthesized using electrochemical polymerization of DMA in oxalic acid. The PDMA film coated onto ITO glass was studied for its chemical structure, morphology, electro-deposition, and electro-activity by FT-IR, TGA, SEM, cyclic voltammetry, and UV-Vis spectrophotometry. The PDMA film showed reversible color changes from yellow to blue representing the transition between the fully reduced state to the fully oxidized state upon switching the potentials. The response time of the PDMA film in term of color change was investigated under various applied potentials and different types of acid electrolyte (HCl and H2SO4). The fast response time of less than 2 sec was observed at the applied potential of 1.6 V. In comparison with HCl, the use of H2SO4 as an electrolyte resulted in the fastest response time. Thus, the PDMA is a potential candidate in electrochromic devices due to its reversible color change and fast response time.

Induced interaction of NH4NO3 with poly(p-phenlene vinylene) by mean of zeolite Y

Chemical sensor technologies play an important role in development and improvement of public health and environment through applications in many areas. Conducting polymers are unique among the sensing materials known to us at present. They have many advantages over conventional metal sensors. Poly(p-phenylenevinylene) (PPV) can serve as the active material in sensor devices because PPV possesses good optical and electrical properties, and it can be synthesized by a relative simple technique. Zeolite is chosen to be introduced into a polymer matrix in order to increase sensitivity toward ammonium nitrate gas. This work will focus on the effect of Si/Al ratio and cation type on the electrical conductivity sensitivity towards the target gas.