Penentuan parameter optimum bagi rawatan pengutuban elektrik ke atas seramik-piezo (BaTiO3) menggunakan sistem buatan sendiri

Kajian ini dijalankan bertujuan untuk menentukan nilai optimum bagi parameter rawatan pengutuban BaTiO3 sebagai bahan seramik-piezo dengan menggunakan sistem pengutuban DC buatan sendiri. Tiga parameter pengutuban utama yang telah dikaji adalah medan elektrik (Ep), suhu (Tp) dan masa (tp) rawatan. Fasa tunggal seramik-piezo BaTiO3 yang stabil dalam struktur hablur tetragon berjaya disediakan melalui persinteran keadaan pepejal konvensional. Pemilihan julat Ep dan Tp untuk rawatan pengutuban masing-masing adalah berdasarkan ujian awal pengukuran histeresis feroelektrik dan penentuan suhu Curie, Tc. Keputusan kajian mendapati BaTiO3 mempunyai nilai medan paksaan, Ec yang kecil (~2.42 kV/cm), pengutuban baki, Pr ~4.90 μC/cm2 dan pengutuban maksimum, Pm yang besar (~17.59 μC/cm2) dengan Tc pada 139°C. Berdasarkan julat parameter kajian, nilai pemalar piezoelektrik, d33 tertinggi ~190 pC/N diperoleh dengan magnitud medan elektrik pengutuban iaitu 1.5Ec pada suhu 60°C selama 10 min. Struktur dan morfologi BaTiO3 selepas rawatan pengutuban juga dikaji. Sistem pengutuban yang dibangunkan menyusun semula penjajaran domain secara efektif dan parameter rawatan optimum didapati setanding dengan kajian BaTiO3 lain

New hybridization approach of titanium organometallic: PANi thin films as room temperature gas sensors

The aim of this research was to investigate the ability of organometallic titanium-PANi hybrid materials as gas sensor at room temperature. To form the hybrid materials, commercially available polyaniline (PANi) powder were directly added into organometallic titanium sols which was synthesized using the sol gel method. The composite films were prepared via spin coating technique followed by electrode deposition for sensors fabrication. Five different organometallic titanium:PANi ratios namely 1 wt% to 5 wt% of PANi were prepared for this experiment. For gas sensing test, all samples were exposed to ethanol vapour. The sensing mode is based on the variation in the electrical conductivity due to the interaction between the gas molecules and the film. It was observed that the composite sensors required appropriate ratio to exhibit optimum sensing properties. This finding proved that the hybridization process is successful and offered much cheaper and easier method for fabrication of room temperature gas senso

Influence of PANi Additions on methanol sensing properties of ZnO thin films

The influence of PANI additions on methanol sensing properties of ZnO thin films at room temperature had been investigated. Commercial polyaniline powder (PANI) was mixed into 3 mL ZnO solution in five different weight percentages namely 1.25, 2.50, 3.75, 5.00 and 6.25% to obtain ZnO/PANI composite solutions. These solutions were spin coated onto glass substrate to form thin films. Microstructural studies by FESEM indicated that ZnO/PANI films showed porous structures with nanosize grains. The thickness of the film increased from 55 to 256 nm, proportionate to increment of PANI. The presence of 2 adsorption peaks at ~310 and ~610 nm in UV-Vis spectrum proved that addition of PANI has modified the adsorption peak of ZnO film. Methanol vapour detection showed that addition of PANI into ZnO dramatically improved the sensing properties of the sensor. The sensors also exhibited good repeatability and reversibility. Sensor with the amount of PANI of 3.75 wt% exhibited the highest sensitivity with response and recovery time was about 10 and 80 s, respectively. The possible sensing mechanism of the sensor was also discussed in this article

Effect of ZnO addition on structural properties of ZnO-PANi/carbon black thin films

The aim of this project was to investigate the effect of ZnO addition on the structural properties of ZnO-PANi/carbon black thin films. The sol gel method was employed for the preparation of ZnO sol. The sol was dried for 24 h at 100°C and then annealed at 600°C for 5 h. XRD characterization of the ZnO powder showed the formation of wurtzite type ZnO crystals. The ZnO powder were mixed into PANi/carbon black solution which was dissolved into M-Pyrol, N-Methyl-2-Pyrrolidinone (NMP) to produce a composite solution of ZnO-PANi/carbon black. The weight ratio of ZnO were 4 wt%, 6 wt% and 8 wt%. The composite solutions were deposited onto glass substrates using a spin-coating technique to fabricate ZnO-PANi/carbon black thin films. AFM characterization showed the decreasing of average roughness from 7.98 nm to 2.23 nm with the increment of ZnO addition in PANi/carbon black films. The thickness of the films also decreased from 59.5 nm to 28.3 nm. FESEM image revealed that ZnO-PANi/carbon black thin films have changed into agglomerated surface morphology resulting in the increment of porosity of the films