Electrical conductive nanocomposite aerogels were synthesized throughin situoxidative polymerization of pyrrole (Py) using ammonium persulfate (APS) as an oxidizing agent in SiO2gels. The effect of Py concentration on the electrical conductivity and physical and morphological properties of aerogels SiO2/PPy was evaluated. B.E.T. analysis indicated that the surface area of the composite SiO2/PPy decreases with increasing concentration of Py. CHN analysis showed an increase in the amount of PPy, from 13 wt.% to 23 wt.%, with increasing concentration of pyrrole synthesis. FTIR-ATR analysis of the composites revealed bands in the region of 1500–1400 cm−1, indicating the presence of the conductive polymer in the silica aerogel as well as the characteristic bands of Si-O-Si and Si-OH covalent bonds. TEM micrographs revealed the presence of particles of PPy with the increased size of the nanoparticles. The composites were successfully applied as passive components, in RC circuits, for low-pass frequency filters. The filters exhibited a cutoff frequency at approximately 435 Hz. The aerogels obtained in this work exhibited suitable electrical conductivity for use in various other applications in electronics.
Inkjet printing presents a high potential for cost reduction of electronic devices manufacturing due to the capacity to deposit materials with high precision, less material waste, and large-scale production through the roll-to-roll printing processes. In this work, a nanostructured TiO2 ink was developed using TiO2 aerogel and an alkaline aqueous solution, which resulted in a very stable suspension. A high-intensity ultrasonic mixer was used to fragment and disperse TiO2 aerogels producing suspensions with particles smaller than 200 nm, which are suitable for the inkjet printing process. For the development of the ink, the viscosity and surface tension were adjusted by using glycerol and a surfactant (Triton X-100). The influence of those components on the properties of the ink was evaluated for different concentrations. After formulation of the inks, the printing parameters were adjusted to optimize the process. Films with high surface area and less than 100 nm grain size were successfully produced. Electrical measurements revealed a resistive-like behavior with the sheet resistance increasing with number of printed layers.
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