Polymer‐BaTiO₃ composites: Dielectric constant and vapor sensing properties in chemocapacitor applications

Abstract

In this work, composite materials, prepared by inclusion of various amounts of BaTiO 3 nanoparticles in PBMA and PHEMA polymer matrices, were characterized in respect to their dielectric properties and then used as the sensing layer of capacitive-type sensors. BaTiO 3 was found to be less effective in enhancing the permittivity of PHEMA, as compared to PBMA, in the range of 1 kHz-1 MHz, possibly due to the observed lower quality of dispersion in the polymer matrix and the higher polarity of the polymer in the former case. The response of the composite-based chemocapacitors to four vapor analytes, covering a wide range of dielectric constants, was studied in relation to the BaTiO 3 load. In all cases, with increasing amount of BaTiO 3 load, the absolute value of capacitance response was increased, due to the corresponding increase of the initial capacitance of the sensing composite layer. However, the corresponding normalized (to the initial capacitance of the sensing composite layer) capacitance values were reduced, due to the decreased volume fraction of the sorbing polymer material in the composite matrix. An exception to this trend, observed upon exposure of the PBMA/BaTiO 3 chemocapacitors to low humidity levels, is also presented and discussed.

Simultaneously harvesting mechanical and chemical energies by a hybrid cell for self-powered biosensors and personal electronics

“…where 3 r(PDMS) is the relative permittivity of the PDMS, 3 r(BTO) is the relative permittivity of the BaTiO 3 nanoparticles, and f f is the volume ratio of BaTiO 3 nanoparticles in the composite material. 19 According to eqn (2), we can obtain the relative permittivity 3 r(composite) of the BaTiO 3 -PDMS composite lm, as shown in Fig. 2d.…”

Manufacture of electrical and magnetic graded and anisotropic materials for novel manipulations of microwaves

“…On the other hand, while ceramics such as BaTiO 3 are brittle and much less versatile with respect to processing, they have bulk permittivities at microwave frequencies that can be orders of magnitude larger than those of polymers [12,13]. Consequently, by dispersing micro-scale particles of BaTiO 3 in a polymer matrix, processable materials with ε up to 20 in the frequency range 12-18 GHz can be obtained [14][15][16][17][18].…”

Controlling dielectric permittivity and dielectric loss by starch‐coated silver nanoparticles in ethylene–propylene rubber

“…Polymer composites with high dielectric permittivity ( ) are of interest for their easy processing, light weight, good mechanical flexibility, and different applications in electronic and electrical industries such as embedded capacitors, sensors and actuators, gate dielectrics, and electromagnetic interference (EMI) shielding . In spite of these unique properties, most of the neat polymers suffer from low dielectric permittivity (about 2–5); therefore, many efforts have been devoted to improve their dielectric permittivity.…”