Molecules (Sep 2022)

Temperature Dependence of the Electrical Properties of Na<sub>2</sub>Ti<sub>3</sub>O<sub>7</sub>/Na<sub>2</sub>Ti<sub>6</sub>O<sub>13</sub>/POMA Composites

  • Salomão Dos Santos Costa,
  • Juliana Pereira da Silva,
  • Matheus Moraes Biondo,
  • Edgar Aparecido Sanches,
  • Marcos Marques Da Silva Paula,
  • Francisco Xavier Nobre,
  • José Anglada Rivera,
  • Yohandys Alexis Zulueta,
  • Milton S. Torikachvili,
  • David Vieira Sampaio,
  • Marcos Vinicius Dias Vermelho,
  • Ştefan Ţălu,
  • Lianet Aguilera Dominguez,
  • Yurimiler Leyet

DOI
https://doi.org/10.3390/molecules27185756
Journal volume & issue
Vol. 27, no. 18
p. 5756

Abstract

Read online

The temperature dependence of the electrical properties of composites formed by biphasic sodium titanate and poly(o-methoxyaniline) (Na2Ti3O7/Na2Ti6O13/POMA) with different concentrations of POMA (0%, 1%, 10%, 15%, 35% and 50%) in the ceramic matrix was determined from measurements of complex impedance. The structural details were studied by means of X-ray diffraction, confirming the formation of the Na2Ti3O7/Na2Ti6O13/POMA composites. The displacement of the (200) reflection from 2θ = 10.45° to 11.15° in the composites with 10 and 15% of POMA suggested the partial replacement of H+ for Na+ in the Na2Ti3O7 structure. The thermal properties were investigated by Thermogravimetry and Differential Thermal Analysis. The Thermogravimetry curves of the composites with POMA content of 1, 10 and 15% presented profiles similar to that of pure sodium titanate sample. The composites with 35 and 50% of POMA showed a process at temperatures around 60–70 °C, which was associated with water absorbed by the polymer. The analysis of the complex impedance spectroscopy measurements revealed that the electrical resistivity of the composites in the range from 0 to 35% increased by two orders of magnitude, with different values for each concentration. This positive temperature coefficient of resistivity was less noticeable in the composite with highest POMA mass content (50%). The rapid increase in resistivity caused an increase in the relaxation time calculated from the time domain. The electrical response of the 50% of POMA compound changes in relation to what was observed in the other compounds, which suggests that there is a saturation limit in the increase in resistivity with POMA content.

Keywords