Rida Farhan

Polylactic acid (PLA) is a biodegradable biopolymer with favorable environmental properties, but its inherent electrical insulation restricts its use in electronics and energy storage applications. To overcome this drawback, polypyrrole (PPy), an intrinsically conductive polymer, has been incorporated into PLA to produce conductive and potentially fully biodegradable composite films via a straightforward solution‐casting process. Structural and morphological analyses by Fourier‐transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) confirmed the successful integration of PPy into the PLA matrix. FTIR revealed interfacial interactions consistent with hydrogen bonding, evidenced by shifts in the PLA carbonyl band and the appearance of characteristic pyrrole vibrations, while SEM showed relatively uniform PPy distribution at low PPy loadings. Thermal characterization, performed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), showed an increase in char residue and modified thermal transitions upon PPy incorporation, indicating enhanced high‐temperature stability and changes in the crystallization behavior of PLA. Electrical measurements demonstrated a percolation‐type increase in surface conductivity from the insulating neat PLA to ~10 ⁻¹ S/m at 20 wt% PPy. Mechanical testing revealed a trade‐off between electrical functionality and structural integrity, with tensile strength decreasing from 2.35 MPa for neat PLA to 0.73 MPa at 15 wt% PPy, attributed to progressive particle aggregation at higher loadings. Electrochemical characterization, using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), identified the 5 wt% PPy composition as optimal, combining markedly enhanced conductivity with low polarization resistance, high capacitance, good rate capability, and moderate mechanical properties. These results demonstrate that PLA/PPy films provide tunable electrical, thermal, and mechanical properties while preserving their biodegradability, making them promising candidates for flexible green supercapacitor electrodes, disposable sensors, and other sustainable electronic devices aligned with circular‐economy principles.

The field of power harvesting has experienced significant growth over the past few years due to the ever-increasing desire to produce portable and wireless electronics with extended lifespans. The present work aims to introduce an approach to harvesting electrical energy from a mechanically excited piezoelectric element and investigates a power analytical model generated by a smart structure of type polyvinylidene fluoride(PVDF) that can be stuck onto fabrics and flexible substrates, although we report the effects of various substrates and investigates the sticking of these substrates on the characterization of the piezoelectric material.

A prototype of rail turnout motor measurement device was designed based on motor torque inspection, using a load cell sensor. A rail turnout is a branched railroad construction to control the railroad track that controlled by turnout motor, therefore it is one of important railways elements for guiding and directing the train to not derailment or collide with another train. The device was made in order to check the reliability of turnout machine in railway systems. In Indonesia, currently the inspection of turnout machine was done manually and still not so efficient in term of the process. Here, we built a portable system device consisted of load sensor, processed with a microcontroller and the data were recorded and displayed in a Liquid Crystal Display (LCD). The device was tested directly to a turnout machine on the railroad at Kiara Condong Station, Bandung, Indonesia. The measured results showed that the device working properly and the average pulling strength of turnout machine at the station was 256.6 ± 2.88 kg.

This study proposes a new model that couples the piezoelectric and electrostrictive behavior to minimize the polarization power of composite polymer. The development of this model is capable to predict the energy harvesting abilities of an electrostrictive composite. To improve the dielectric permittivity of electrostrictive polymer, the particles of PZT have been incorporated in order to increase the conversion efficiency of the composite. Dielectric characterization tests showed an increase in dielectric permittivity by a factor of 4.5 compared to pure polymer. Experimental measurements of harvested power validate the analytical model and demonstrate a good correlation between the two data. An equivalent of an electrical scheme has been developed, which allows modeling the two behaviors. The harvested power density under low frequency at 2% of strain can reach 0.30 μW/cm³ for 33% of PZT without the polarization field, including the conversion efficiency becomes higher. The energy harvester property of this material composite has excellent potential for several self‐powered applications such as wireless sensor networks and the internet of things.

The field of power harvesting has experienced significant growth over the past few years due to the ever-increasing desire to produce portable and wireless electronics with extended lifespans. The present work aims to introduce an approach to harvesting electrical energy from a mechanically excited piezoelectric element and investigates a power analytical model generated by a smart structure of type polyvinylidene fluoride(PVDF) that can be stuck onto fabrics and flexible substrates. Moreover, we report the effects of various substrates and investigates the sticking of these substrates on the characterization of the piezoelectric material.