Synthesis of poly [2,3,5,6-tetrafluoro-4-(trifluoromethyl) phenylaminophosphazene]/LiNbO3 nanocomposites and characterization of their morphological, mechanical, and piezoelectric behavior for energy harvesting applications

Abstract

The use of polymer nanocomposites for piezoelectric energy harvesting applications has created exciting opportunities in flexible electronics. In this research, we synthesized poly [2,3,5,6-tetrafluoro-4-(trifluoromethyl)phenylaminophosphazene (PTPP)]/LiNbO₃ nanocomposites by incorporating trigonal crystalline lithium niobate nanoparticles (average particle size ∼ 45 nm) into PTPP via solution casting method. Further, we investigated the effects of different concentrations of lithium niobate (LiNbO₃) nanoparticles on the thermal, mechanical, and piezoelectric performance of the PTPP nanocomposites. The synthesized nanocomposites exhibited strong interfacial interactions between the organic and inorganic phases, resulting in a uniform morphology across all compositions, except for the 8 % loading, which showed some agglomeration. Additionally, both PTPP and its nanocomposites demonstrated high thermal stability, with the highest char yield of 64.1 % observed at 8 % LiNbO₃ loading. Mechanical testing revealed a significant improvement in tensile strength (224 %) and a reduction in elongation at break (34.4 %) with 8 % LiNbO₃ loading. These enhancements in thermal and mechanical properties were attributed to the presence of strong C-F bonds and LiNbO₃ content in the nanocomposites. Besides this, dynamic mechanical analysis indicated that 8 % LiNbO₃-loaded PTPP nanocomposite also exhibited the lowest tan δ value of 0.68 and the highest energy storage capacity with minimal loss over a high-temperature range due to the restricted mobility of polymer chain with the addition of nanoparticles. PTPP also exhibited a piezoelectric effect with a coefficient of 26.4 pC/N, which was further enhanced by the incorporation of LiNbO₃, reaching a maximum increase of 6.4 %. These novel nanocomposites show great potential for energy-harvesting applications in electronic devices.