Dielectric and Mechanical Properties of PDMS-La2Ba2XZn2Ti3O14 (X = Mg/Ca/Sr) Nanocomposites

Suryakanta Nayak; Banalata Sahoo; Tapan Kumar Rout; Amar Nath Bhagat

doi:10.1021/acsomega.3c04538

Dielectric and Mechanical Properties of PDMS-La₂Ba₂XZn₂Ti₃O₁₄ (X = Mg/Ca/Sr) Nanocomposites

ACS Omega. 2023 Sep 25;8(40):37090-37097. doi: 10.1021/acsomega.3c04538. eCollection 2023 Oct 10.

Authors

Suryakanta Nayak^{1

2

3

4}, Banalata Sahoo^{5

6}, Tapan Kumar Rout⁴, Amar Nath Bhagat⁴

Affiliations

¹ Rubber Technology Centre, Indian Institute of Technology, Kharagpur, West Bengal 721302, India.
² Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117575, Singapore.
³ Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Singapore.
⁴ R&D, Surface Engineering Research Group, Tata Steel Limited, Jamshedpur 831001, India.
⁵ Department of Chemistry, Indian Institute of Technology, Kharagpur, West Bengal 721302, India.
⁶ Department of Chemistry, Regional Institute of Education, Bhubaneswar, Odisha 751022, India.

Abstract

Flexible polydimethylsiloxane-La₂Ba₂XZn₂Ti₃O₁₄ (X = Mg/Ca/Sr) [PDMS-LBT] nanocomposites with high permittivity (dielectric constant, k) are prepared through a room-temperature mixing process. The LBT nanoparticles used in this study are prepared through a high-temperature solid-state reaction. It is observed that LBT (X = Mg/Ca) nanoparticles are spherical in nature, with particle size ∼20 nm, as observed from the HRTEM images, whereas LBT (X = Sr) nanoparticles are cubical in nature with particle size ≥100 nm. These LBT (X = Mg/Ca/Sr) nanoparticles are crystalline in nature, as apparent from the XRD analysis and SAED patterns. The permittivity of LBT nanoparticles is higher when "Ca" is present in place of "X". These three oxides show a temperature-dependent dielectric behavior, where LBT nanoparticles with "Sr" show a sharp change in permittivity at a temperature of ∼105 °C. These kinds of oxide materials, especially LBT (X = Sr) nanoparticles/oxides, can be used in dielectric/resistive switching devices. The effect of LBT nanoparticle concentration on the dielectric and mechanical properties of PDMS-LBT nanocomposites is widely studied and found that there is a significant increase in dielectric constant with an increase in the concentration of LBT nanoparticles. There is a decrease in the volume resistivity with the increase in the LBT nanoparticle concentration. All the PDMS-LBT nanocomposites have low dielectric loss (ε″) compared to the dielectric constant value. It is found that both permittivity (ε') and AC conductivity (σ_ac) of PDMS-LBT composites are increased with the temperature at a frequency of 1 Hz. The % elongation at break (% EB) and tensile strength (TS) decrease with the LBT nanoparticle concentration in the matrix PDMS, which is due to the non-reinforcing behavior of LBT nanoparticles. The distribution and dispersion of LBT nanoparticles in the matrix PDMS are observed through HRTEM and AFM/SPM.