Polyaniline remains one of the most extensively investigated conducting polymers. It is characterized by low fabrication costs, easy synthesis process and tunable conductivity. Nonetheless, pristine polymer exhibits a number of deficiencies limiting its further commercialization due to its low mechanical flexibility, conductivity reduction in neutral and alkaline solutions, and degradation during electrochemical cycling. Among many approaches proposed for overcoming these problems, the formation of composite materials with various carbon nanomaterials appears promising. Recent studies have demonstrated that PANI-carbon nanocomposites exhibit significantly enhanced electrochemical, mechanical, and optical properties compared to pristine PANI, with remarkable improvements in specific capacitance, cycling stability, switching speed, and adsorption capacity across diverse applications. For instance, PANI-carbon composites achieve exceptional capacitance (696.75 F g -1 vs. 274.75 for pure PANI) with 93.57% retention over 3,500 cycles vs. 72.3% after 2500 charge/discharge cycles for pure PANI, enhanced electrochromic contrast (0.52 vs. 0.38 for pure PANI), high CO 2 capture and superior pollutant adsorption with rapid kinetics. Despite extensive research, critical gaps remain: limited systematic comparison of synthesis methods, unclear structure-property correlations and narrow application focus. Additionally, some current limitations that need further addressing will be outlined. In this review paper, PANI/carbon nanomaterial composites are critically analyzed. Specifically, the major synthesis techniques applied for these compounds and the resulting structures, electrochemical properties, and applications of such composites will be described.
Diamond-like carbon (DLC) films have emerged as key materials for enhancing the performance, reliability, and durability of microsystems and microdevices. This perspective article presents an analysis of the scientific and technological evolution of DLC from a conventional protective coating to a multifunctional platform material for microsystems and microdevices. Recent advances in tailoring the mechanical, electrical, chemical, and surface properties of DLC have been discussed, highlighting its potential to mitigate friction, adhesion, and wear in microelectromechanical systems (MEMS), while enabling new functionalities in microsensors, biomedical devices, and microelectronic platforms. Despite significant progress, several challenges continue to hinder broader technological adoption, including residual stress management, low-temperature deposition compatible with complementary metal–oxide–semiconductor (CMOS) processes, large-area scalability, and long-term reliability under demanding operating conditions. Future developments are expected to rely on engineered DLC architectures, such as doped, multilayer, and nanostructured films, combined with advanced surface functionalization and intelligent process optimization to meet application-specific requirements. Furthermore, the need for standardized integration strategies that bridge the gap between laboratory-scale research and industrial manufacturing is emphasized.
Jamily L. Santos, Rayanne O. Araujo, Flaviana C. P. Ribeiro, Mariana N. Guimarães, Victoria M. R. Lima, Luiz Kleber C. De Souza
The exponential growth in plastic consumption results in unwanted accumulation on the streets of most cities due to inadequate plastic disposal, landfills overloading, and pollution of the soil, atmosphere, and oceans. This work aims to investigate the use of PET (polyethylene terephthalate) waste to produce solid acid catalysts. The catalysts were synthesized via chemical activation with ZnCl 2 or K 2 CO 3, followed by carbonization in an inert atmosphere and sulfonation. Catalytic tests were carried out on the esterification reaction of oleic acid and methanol. The best result was obtained using zinc chloride as an activating agent, functionalized at 80 °C for 2 h. Carbonaceous materials were obtained with S BET, V t, V mic, and V mes of 272 m 2 g -1, 0.36 cm 3 g -1, 0.14 cm 3 g -1, and 0.22 cm 3 g -1, respectively. An 88% conversion to methyl oleate was observed. The synthesis of a heterogeneous acid catalyst is a sustainable and promising alternative for reusing PET waste.
L. K. Aishwaryaa, S. Chitra, R. Hema, M. Sundararajan
When a common power supply is shared by analog and digital circuits on a high-frequency mixed-signal board, noise generated by high-speed digital circuits propagates through the power delivery network (PDN) and degrades the performance of sensitive analog blocks. This work investigates power integrity enhancement using diamond-based via-loaded square power island (SPI) metamaterial structures over the frequency range of 0–20 GHz. The integration of diamond as a dielectric material, owing to its low loss tangent, high thermal conductivity, and stable permittivity, significantly improves high-frequency noise suppression and thermal performance. The proposed structure achieves a peak suppression of approximately −72 dB at 14 GHz and maintains suppression better than −30 dB across the 8–20 GHz frequency band. The results are validated through full-wave electromagnetic simulations, demonstrating the effectiveness of the proposed design in enhancing power integrity and reliability in high-frequency mixed-signal PDNs.
Controlling nitrogen functionalities in graphene are crucial for high-performance supercapacitors. In this study, we report the scalable synthesis of nitrogen-doped reduced graphene oxide (N-rGO) via a hydrothermal process using readily available inorganic precursors in an aqueous phase, enabling controlled manipulation of nitrogen functionalities. The optimized N-rGO (GO:aqueous NH 3 = 1:6) exhibits a areal capacitance of 0.4 F cm −2 at a scan rate of 5 mV s −1. In a symmetric two-electrode system, N-rGO delivers a high specific capacitance of 532 F g −1, along with an energy density of 41 Wh kg −1 and a power density of 375 W kg −1 at 0.5 A g −1, with a capacitance retention of ∼78% after 10,000 cycles at 1.96 V. These performance metrics are attributed to an optimal defect concentration combined with a high proportion of amino and pyrrolic nitrogen functionalities. Quantum capacitance calculations reveal an enhanced electronic density of states near the Fermi level, thereby improving charge storage performance.
