Research Scholars http://localhost:8080/xmlui/handle/123456789/1 2026-04-29T10:06:46Z 2026-04-29T10:06:46Z Arti, Arti http://localhost:8080/xmlui/handle/123456789/6095 2026-04-21T10:08:53Z 2025-07-01T00:00:00Z

Study of Charge Transport Mechanism in Polypyrrole based Nanocomposites for Electrical Applications Arti, Arti The Conductive Polymers (CPs) represent a novel category of materials that combine the remarkable properties of metals and plastics. They exhibit significant conductivity when doped with suitable fillers makes them a viable alternative to metallic conductors and semiconductors. Due to their remarkable properties, such as lightweight, ease of processing, cost-effectiveness, high cyclability, and excellent mechanical, thermal, and environmental stability, as well as high specific capacitance and improved conductivity, CPs have found applications in various fields, including organic light-emitting diodes, energy storage devices, solar cells, chemical and gas sensors and flexible electronics. Among various conducting polymers, Polypyrrole (PPy) has garnered significant attention, which lies in poly-heterocyclic family of conductive polymers. Its electrical and optical properties are comparable to those of inorganic semiconductors and metals. Despite its excellent properties, PPy has certain limitations, such as being weak, fragile, having low mechanical properties, being non-biodegradable, and exhibiting relatively poor thermal stability in air, which restricts its practical applications. A review of the literature indicates various strategies to enhance the properties of PPy, such as doping, developing nanostructures, and creating nanocomposites. Consequently, in the present study, PPy-based nanocomposites with Tin-Oxide (SnO2), reduced Graphene Oxide (rGO), and MoS2/rGO have been synthesized with different concentrations of the fillers in the PPy matrix. Additionally, in the last phase of the present work, surfactant-directed PPy nanoparticles have also been synthesized using different concentrations of Camphor Sulphonic Acid (CSA), which is an anionic surfactant. Structural and morphological properties of all prepared nanocomposites have been analyzed through X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Raman spectroscopic techniques. Further, the DC conductivity and EMI shielding properties of all the samples have been studied, and their results have been interpreted in terms of the change in their structural properties as a result of loading different fillers in the PPy matrix. The present study of hybrid nanocomposites in PPy makes them suitable over metal-based EMI shields. Irrespective of metal-based EMI shields, the absorptiondominated total shielding effectiveness suggests that the PPy-based nanocomposite may be a novel material for the development of efficient EMI shielding devices for industrial applications. Dr. PARVEEN KUMAR

2025-07-01T00:00:00Z Sharma, Anita http://localhost:8080/xmlui/handle/123456789/6094 2026-04-21T10:05:57Z 2024-10-01T00:00:00Z

Synthesis and Characterization of Polyaniline and its Composites for Opto Electrical Sensing Applications Sharma, Anita Ammonia (NH3) is a widely used chemical in various chemical production, industrial, agriculture (fertilizers), and refrigeration. The need for ammonia sensors arises from the toxic, corrosive, and environmentally damaging properties of NH3. Reliable and efficient ammonia sensors are vital for maintaining safe workplaces, protecting the environment, and complying with safety and environmental regulations. Traditionally, pure organic ammonia sensors (e.g., Polyaniline, Polypyrrole) are advantageous for applications requiring room temperature operation, flexibility and low-cost fabrication, but they are limited by lower stability, slower response, and poor selectivity. Pure inorganic ammonia sensors (e.g., Metal Oxides: ZnO, SnO2) offer high sensitivity, fast response times, and stability in harsh conditions but require high temperatures, making them less suitable for portable, low-power applications and limiting their mechanical flexibility. These drawbacks drive the need for organic-inorganic hybrid sensors, which can combine the best properties of both material types-addressing limitations like poor selectivity, slow response, and environmental instability while providing the higher sensitivity and more stable performance. This thesis investigates the synthesis of pure polyaniline and its composites with ZnO, SnO2, and rGO for improvements in structural, optical, electrical, and gas sensing properties. Polyaniline and its composites with ZnO, SnO2, and rGO offer significant improvements in the sensitivity, response time, and stability of ammonia sensors. These materials are highly desirable for developing reliable and efficient ammonia sensors for industrial, environmental, and safety applications. Polyaniline- based composites show great potential for addressing the limitations of traditional sensors, providing a promising solution for real-time ammonia monitoring. Our study demonstrates notable improvements in the sensing capabilities, as well as enhanced selectivity and stability, of polyaniline composite materials, establishing them as effective solutions for ammonia detection and for ensuring environmental safety and protection. Kumar, Parveen

2024-10-01T00:00:00Z Singh, Pooja http://localhost:8080/xmlui/handle/123456789/6093 2026-04-21T10:00:40Z 2024-11-01T00:00:00Z

Mechanical and Tribological Properties of Carbon Reinforced Polymer Nanocomposites Singh, Pooja In the field of material science, various polymers have been reinforced for many years with either inorganic or organic fillers. The production of polymeric composites with different types of fillers as reinforcements has gained significant attention. A broad variety of variations in the characteristics of polymeric composites have been demonstrated by experimental results from various research groups in the literature. Epoxy resin, a thermosetting polymer is a prominent class of polymers due to its high mechnaical strength, high chemical and thermal properties, dimensional integrity, good adhesion, and solvent resistance. It has a wide spread of applications in the aerospace, civil, and automobile industries, but its brittle nature and poor toughness restrict its use in many industries. Its high crosslinked structure is responsible for epoxy resin’s poor toughness and brittleness. To address these issues, a variety of fillers have been incorporated within epoxy resin without losing their ability to perform as intended. Among those fillers, nanomaterials are fascinating yet challenging materials that improve the brittleness and toughness of epoxy polymers. They are exciting fillers due to their outstanding physical and chemical characteristics and large surface area-to-volume ratio. Several investigations have been carried out on adaptable epoxy nanocomposites based on MWCNT, glass fiber, carbon fiber, graphene nanoplatelets, carbon nanofiber, fly ash, ZnO, Al2O3, GO, RGO, TiO2, SiO2, ZrO2, etc. nanomaterials. However, the research studies on carbon nanomaterials and rare earth metal oxides reinforced epoxy nanocomposites are still very limited. In this current doctoral work, carbon nanomaterials (MWCNT & RGO) and rare-earth metal oxide (Y2O3) are used to reinforce with epoxy polymer matrix to investigate its mechanical, thermal and tribological properties of epoxy nanocomposites and their hybrids. With the aim to synthesize the epoxy nanocomposites using carbon nanomaterial and rare earth metal oxide nanomaterial, firstly pure epoxy polymer has been optimized and their basic characterization like FTIR, XRD and Raman spectroscopy are done to investigate their chemical bonds and crystal structure. Also, same characterization is done for all the nanofillers to investigate their functional groups and chemical bonding. Then the experimental synthesis parameters are optimized for ultrasonic dual mixing method to fabricate the epoxy nanocomposites. The effect of different reinforcements in epoxy polymer with MWCNT, RGO and Y2O3 are further analysed to improve the mechanical, tribological and thermal properties of fabricated epoxy nanocomposites. The hybrid nanocomposites by combining these single fillers are fabricated and their exciting and synergetic properties due to the combination of the constituent properties is investigated. For mechanical testing static and dynamic mechanical analysis is investigated and for thermal properties differential scanning calorimetry is used to v investigate the glass transition temperature of nanocomposites. Tribological properties is investigated by wear and friction testing using the Pin-On-Disc instrumentation. The results of the testing showed that used carbon nanomaterial and rare earth metal oxides at optimized compositions are successfully improved the properties of the epoxy polymer. All optimized nanocomposites are then used to fabricate the similar and dissimilar adhesive joints at different weights. Adhesive joints are found the most suited joints for structural applications among all other mechanical joints. Some of the key advantages that adhesive-bonded joints are believed to offer are excellent corrosion resistance, notable weight and noise reduction, significant damping capabilities, and exceptional thermal and insulating properties. The outcomes of this work anticipate that the similar adhesive lap joint of the mechanically polished aluminium was found stronger as compared to the mechanically polished steel and the lap shear test results showed the maximum lap shear strength and % elongation for similar aluminium joints using pure epoxy adhesives as well as for optimized nanocomposite adhesive than the similar steel joints and dissimilar ones. Therefore, the synthesized nanocomposites are useful for the adhesive joints in various structural applications. Thus, the current work has potential for industrial contributions Dr. ARUN KUMAR and Dr. SWATI SHARMA

2024-11-01T00:00:00Z Ankita, Ankita http://localhost:8080/xmlui/handle/123456789/6092 2026-04-21T09:57:29Z 2024-09-01T00:00:00Z

Bandgap Tuning And Magnetism In Cerium Oxide Based Nanocomposites Ankita, Ankita The increasing concern for environmental sustainability has led to enhance interest in developing efficient, sustainable, and cost-effective methods for wastewater treatment. As industrialization and urbanization accelerate, the complexity and diversity of pollutants present in industrial, agricultural, and municipal wastewater have rendered traditional water purification methods insufficient. Conventional methods such as coagulation, filtration, and chemical oxidation are often ineffective against a wide range of contaminants, including Persistent Organic Pollutants (POPs), dyes, heavy metals, and pharmaceutical residues. These pollutants pose significant threats to ecosystems and public health, necessitating the development of advanced water treatment technologies. Among the emerging solutions, photocatalysis has garnered significant attention due to its ability to harness solar or artificial light energy to drive oxidative and reductive reactions, leading to the degradation of harmful substances into non-toxic by-products, primarily water and carbon dioxide. Cerium Oxide (CeO2), a rare earth metal oxide, has been recognized for its outstanding photocatalytic and catalytic properties, which are mainly attributed to its redox behavior, high Oxygen Storage Capacity (OSC), and its ability to generate Reactive Oxygen Species (ROS). In particular, intrinsic ability of CeO2 to absorb UV light and generate electron-hole pairs under irradiation has shown promise in decomposing organic pollutants. However, to achieve higher efficiency under visible light crucial for practical applications given the broad solar spectrum CeO2 needs to be modified through doping or by creating composite materials with enhanced photocatalytic performance. This research work investigates the photocatalytic activity and magnetic properties of pure CeO2 nanoparticles and its doped variants with Europium (Eu), Gadolinium (Gd), Activated Carbon (AC), and nanofiber composites. The goal of this research is to enhance the UV light driven photocatalytic efficiency of CeO2 while simultaneously improving its magnetic properties. Doping with Eu and Gd was chosen based on their electronic configurations and proven ability to shift bandgap of CeO2 toward the UV light region. Europium and gadolinium, both rare earth elements, can introduce intermediate energy states within band structure of CeO2, thereby promoting the utilization of UV light photons for more efficient pollutant degradation. Additionally, their presence enhances charge separation by preventing the rapid recombination of photo-generated electron-hole pairs, a common issue that limits the photocatalytic performance of undoped CeO2. This improved charge separation leads to a higher quantum yield of reactive oxygen species such as hydroxyl radicals, which are highly effective in breaking down organic molecules in wastewater. Our research revealed that both Eu- and Gd-doped CeO2 showed a significant increase in the degradation rate of organic dyes such as Rose Bengal (RB) dye under UV light irradiation, compared to iv pure CeO2. The magnetic properties of doped CeO2 are of particular interest due to their potential application in the magnetic separation techniques. By inducing the ferromagnetism through doping, the photocatalyst can be easily recovered from the treated water via an external magnetic field, reducing operational costs and preventing secondary contamination. Our findings demonstrate that Eu- and Gd-doped CeO2 exhibit enhanced magnetic properties, facilitating their separation from solution post-treatment without compromising their photocatalytic efficiency. The incorporation of Activated Carbon (AC) and nanofiber composites further amplifies the photocatalytic activity and stability of the CeO2 based materials. Activated carbon, known for its large surface area and excellent adsorption capabilities, serves as a support material that enhances the adsorption of pollutants onto the catalyst surface, thus increasing the availability of contaminants for photocatalytic degradation. Moreover, activated carbon helps in trapping the photo-generated electrons, further mitigating electron-hole recombination and boosting photocatalytic efficiency. Nanofiber composites, on the other hand, contribute to structural integrity and mechanical stability, which are critical for the longevity of the photocatalyst. The nanofiber framework not only offers additional surface area but also improves the dispersion of CeO2 particles, thereby facilitating better light absorption and reaction kinetics. The hybridization of CeO2 with nanofibers and activated carbon offers a multifunctional material with superior performance in wastewater treatment applications. In conclusion, the development of CeO2 based materials doped with europium, gadolinium, and integrated with activated carbon and nanofibers represents a significant advancement in the field of photocatalysis. These multifunctional materials not only exhibit superior photocatalytic efficiency under UV light but also offer the practical advantage of magnetic recovery, making them highly suitable for sustainable and scalable wastewater treatment solutions. This research highlights the potential of tailored photocatalytic materials to meet the growing demand for clean water and contribute to global efforts toward environmental protection. Dr. PARMOD KUMAR

2024-09-01T00:00:00Z