Department of Chemistry
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Item BIOINSPIRED MULTIFUNCTIONAL SILVER NANOPARTICLES FOR OPTICAL SENSING APPLICATIONS: A SUSTAINABLE APPROACH(ACS Publications, 2023-10-18) Kshitij RB, Singh; Arunadevi, Natarajan; Shyam S, PandeySilver nanoparticles developed via biosynthesis are the most fascinating nanosized particles and encompassed with excellent physicochemical properties. The bioinspired nanoparticles with different shapes and sizes have attracted huge attention due to their stability, low cost, environmental friendliness, and use of less hazardous chemicals. This is an ideal method for synthesizing a range of nanosized metal particles from plants and biomolecules. Optical biosensors are progressively being fabricated for the attainment of sustainability by using opportunities offered by nanotechnology. This review focuses mainly on tuning the optical properties of the metal nanoparticles for optical sensing to explore the importance and applications of bioinspired silver nanoparticles. Further, this review deliberates the role of bioinspired silver nanoparticles (Ag NPs) in biomedical, agricultural, environmental, and energy applications. Profound insight into the antimicrobial properties of these nanoparticles is also appreciated. Tailor-made bioinspired nanoparticles with effectuating characteristics can unsurprisingly target tumor cells and distribute enwrapped payloads intensively. Existing challenges and prospects of bioinspired Ag NPs are also summarized. This review is expected to deliver perceptions about the progress of the next generation of bioinspired Ag NPs and their outstanding performances in various fields by promoting sustainable practices for fabricating optical sensing devices.Item MOLECULARLY IMPRINTED POLYMER-BASED OPTICAL IMMUNOSENSORS(John Wiley & Sons, 2023-04-11) Kshitij R. B., Singh; Arunadevi, NatarajanMolecularly imprinted polymers (MIPs) are artificial antibodies for a target molecule. The review focuses mainly on mechanistic steps involved in forming MIPs and the role of co-monomers and porogen. In addition, the electronic transition between different energy levels is explained with the help of the Jablonski diagram. Diverse receptor and target molecules for anchoring artificial MIPs are discussed, accentuating the synergetic effects obtained. The binding efficiency, selectivity, and sensitivity of various optical sensors are discussed intensively. In addition to this, we focused on synthesis, physical forms, characterization techniques, and microorganism detection of imprinted polymers. A brief investigation on the use of MIPs in cancer diagnosis is also included, and attention is extended to the important challenges faced in using imprinted polymers.Item GREEN NANOBIOPOLYMERS FOR ECOLOGICAL APPLICATIONS: A STEP TOWARDS A SUSTAINABLE ENVIRONMENT(Royal Society of Chemistry, 2023-04-20) Preeti, Chincholikar; Kshitij RB, Singh; Arunadevi, Natarajan; Rout George, Kerry; Jay, Singh; Jitendra, Malviya; Ravindra, Pratap SinghTo minimize the usage of non-renewable resources and to maintain a sustainable environment, the exploitation of green nanobiopolymers should be enhanced. Biopolymers are generally developed from various microorganisms and plants in the specified condition. This review article discusses the current advances and trends of biopolymers, particularly in the arena of nanotechnology. In addition, discussion on various synthesis steps and structural characterization of green polymer materials like cellulose, chitin, and lignin is also encompassed. This article aims to coordinate the most recent outputs and possible future utilization of nanobiopolymers to the ecosystem with negligible effects by promoting the utilities of polymeric materials like polycaprolactones, starch, and nanocellulose. Additionally, strategic modification of cellulose into nanocellulose via rearrangement of the polymeric compound to serve various industrial and medical purposes has also been highlighted in the review. Specifically, the process of nanoencapsulation and its advancements in terms of nutritional aspects was also presented. The potential utility of green nanobiopolymers is one of the best cost-effective alternatives concerning circular economy and thereby helps to maintain sustainability.Item MANNOSE: A POTENTIAL SACCHARIDE CANDIDATE IN DISEASE MANAGEMENT(Springer Link, 2023-01-20) Dhanalakshmi, M; Sruthi, D; Jinuraj, K. R; Kajari, Das; Sushma, Dave; Muthulakshmi Andal, N; Jayashankar, DasThere are a plethora of antibiotic resistance cases and humans are marching towards another big survival test of evolution along with drastic climate change and infectious diseases. Ever since the first antibiotic [penicillin], and the myriad of vaccines, we were privileged to escape many infectious disease threats. The survival technique of pathogens seems rapidly changing and sometimes mimicking our own systems in such a perfect manner that we are left unarmed against them. Apart from searching for natural alternatives, repurposing existing drugs more effectively is becoming a familiar approach to new therapeutic opportunities. The ingenious use of revolutionary artificial intelligence-enabled drug discovery techniques is coping with the speed of such alterations. D-Mannose is a great hope as a nutraceutical in drug discovery, against CDG, diabetes, obesity, lung disease, and autoimmune diseases and recent findings of anti-tumor activity make it interesting along with its role in drug delivery enhancing techniques. A very unique work done in the present investigation is the collection of data from the ChEMBL database and presenting the targetable proteins on pathogens as well as on humans. It shows Mannose has 50 targets and the majority of them are on human beings. The structure and conformation of certain monosaccharides have a decisive role in receptor pathogen interactions and here we attempt to review the multifaceted roles of Mannose sugar, its targets associated with different diseases, as a natural molecule having many success stories as a drug and future hope for disease management.Item GRAPHENE OXIDE INTEGRATED INTO PROTECTIVE COATINGS AGAINST CORROSION FOR METALS AND ITS ALLOYS: A REVIEW(International Journal of Corrosion and Scale Inhibition, 2022-04-02) Priyanka, D; Vinuchakravarthi, S; Nalini, D; Quraishi, M.A; Chauhan, D.S.This review aims to discuss the effect of graphene oxide (GO) derivatives incorporated protective coatings on various metals against corrosion process in alkaline environments. These coatings increased hydrophobic character and adhesion strength between the coating and metal surface. Electrochemical measurements were used more often among all other techniques to investigate the effect of inhibitor in the polymer matrix (epoxy/silane sol). In some cases, the highest inhibition efficiency was achieved by electrochemically coating GO derivatives on the metal surface. GO derivatives prepared via the adsorption of Pr3+, Ce3+ ,and Zn2+ ions have revealed a good inhibition tendency for metals in acidic solution because of the exchange of Pr3+, Ce3+, and Zn2+ with those ions (Na+ ,Cl–) in the corrosion electrolyte. Further, because of the adsorption of polar groups on GO onto the surface of metals, the hydrophobicity achieved by modified GO coating limits the infiltration of corrosive ions and enhances inhibitory efficiency. And, scratches were foreseen during the manufacturing of coatings on metallic substrates, and this harms the organic coatings. The defect created by impurities developed coatings deterioration that was prone to the diffusion of corrosive substances, severely reducing the coatings’ lifespan. Grafting graphene oxide with various functional groups was used to achieve self-healing behavior in organic coatings. At the defective site of the metallic substrates, self-healing by functionalized graphene oxide created dense protective coatings.Item ACTIVE-POLYPHENOLIC-COMPOUNDS-RICH GREEN INHIBITOR FOR THE SURFACE PROTECTION OF LOW CARBON STEEL IN ACIDIC MEDIUM(World Scientific Publishing Co Pte Ltd, 2019) ILL-MIN, CHUNG; VENKATESAN, HEMAPRIYA; PONNUSAMY, KANCHANA; NATARAJAN, ARUNADEVI; SUBRAMANIAN, CHITRA; SEUNG-HYUN, KIM; MAYAKRISHNAN, PRABAKARANEco-friendly biodegradable Rhododendron schlippenbachii (R. schlippenbachii) green inhibitors, R. schlippenbachii methanolic (RSMeOH) extract, which can effectively reduce low carbon steel corrosion rate, were investigated using weight-loss and electrochemical (electrochemical impedance spectroscopy) techniques. The inhibitors exhibited higher efficiency by retarding the corrosion process in 1M H2SO4 and the inhibition efficiency is found to be concentration dependent. The reactivity of the predominant phytochemical components of the extract are analyzed. The adsorption of inhibitors on low carbon steel is followed the Langmuir adsorption. The protective inhibitor film formed on the metal surface was confirmed by SEM and AFM techniques.Item ISOLATION, SPECTROSCOPIC AND THERMAL PROPERTIES OF HYDRAZINIUM TRIS(OXYDIACETATO)LANTHANATE(III) HEMI(PENTAHYDRATE)(Springer Nature, 2017-02-21) Kanchana, P; Packiaraj, S; Pushpaveni, A; Govindarajan, SOil-bath reaction of respective metal nitrate with an aqueous mixture of oxydiacetic acid (H2oda) and hydrazine hydrate led to the formation of crystalline compounds with formula (N2H5)3[Ln(oda)3]·2.5H2O (where Ln = La, Ce, Pr, Nd and Sm), which are stable for a week and undergo efflorescence. The resulting complexes were characterized by infrared spectral, thermal (air and nitrogen atmosphere), UV–visible and PXRD studies. From the thermal studies, both in air and nitrogen atmosphere, these compounds show endothermic dehydration below 100 °C to give anhydrous compounds. Next, the anhydrous compounds (in air) undergo endothermic decomposition between 190 and 225 °C to form Ln(Hoda)3 intermediate, which further show exothermic decomposition to yield respective metal oxide as the end residue. But, in nitrogen atmosphere, the same anhydrous compounds exhibit endo-followed by exothermic decompositions to give respective metal as end product. This is observed as a continuous single step of decomposition in TG. The structure of (N2H5)3[Nd(oda)3]·2.5H2O has been determined by single-crystal X-ray analysis. The neodymium atom is coordinated by nine oxygen atoms from three tridentate (O, O, O) oxydiacetate ions with tricapped trigonal prismatic geometry. In addition, both the parent acid and its compounds display strong fluorescent emission due to the ligand, which renders them as fluorescent materials at room temperature.Item SODIUM ION BATTERIES: A NEWER ELECTROCHEMICAL STORAGE(John Wiley & Sons, Inc, 2014-07-24) Nithya, C; Gopukumar, SVehicle electrification is one of the most significant solutions that address the challenges of fossil fuel depletion, global warming, CO2 pollution, and so on. To mitigate these issues, recent research mainly focuses on finding clean energy storage devices such as batteries, supercapacitors, fuel cells, and so forth. Owing to the outstanding energy and power density, lithium-ion batteries (LIB) have captured the market for portable electronics, hybrid electric vehicles, plug-in hybrid electric vehicles, and so on. During 1970–1980s, electrode materials for both LIBs and sodium-ion batteries (NIBs) were investigated but higher energy and power density of LIBs have made it a popular candidate for portable electronics. Issues arise on the availability of lithium reserves, so it is high time we take a look at finding alternative energy storage system without compromising on the energy and power density of the state-of-the-art LIBs. Therefore, researchers have revisited NIBs and recent developments have contributed towards discovering new electrode materials to match the energy and power density of LIBs at low cost. While a variety of positive and negative electrode materials have been investigated for NIBs so far, the influence of voltage, capacity, cycle life, and volume expansion of negative electrodes on Na+ ion extraction and insertion are more as compared with LIBs. This affects the energy and power density of NIBs but cost-effective partial replacement of LIBs is viable and is widely pursuedItem DESIGNING A CORROSION RESISTANCE SYSTEM USING MODIFIED GRAPHENE OXIDE-EPOXY MICROCAPSULES FOR ENHANCING THE ADHESION STRENGTH OF THE EPOXY COATINGS(Elsevier B.V, 2022-06-20) Priyanka D; Nalini DNew microencapsulated material with advanced corrosion resistance activity and superior adhesion strength on the steel sample was synthesized by in-situ polymerization. In this process, urea-formaldehyde was used as capsule shell material for encapsulating modified graphene oxide. The formation of microcapsules was effectively evidenced by FT-IR, SEM, and TGA-DSC analyses. Initially, graphene oxide was modified by the adsorption of Catharanthus roseus L. (C.R) leaves extract and characterized by FT-IR, SEM, EDX, and DFT studies. GO-C.R and UF-GO-C.R (microcapsules) were separately impregnated into epoxy resin and fabricated on the steel substrates. The anti-corrosion performance of UF-GO-C.R/Epoxy in comparison with neat GO-C.R/Epoxy coated sample was evaluated by electrochemical impedance spectroscopy (EIS) and salt spray test. Results reveal that UF-GO-C.R microcapsules in epoxy matrix showed the protection efficiency of 83.6 % after the immersion period of 7 days in 3.5 % NaCl solution which was relatively higher than those with neat GO-C.R. In addition, the coating loaded with UF-GO-C.R microcapsules showed improvement in the adhesion of epoxy coatings on the steel surface which was evident from the increase in peel strength (290 N) through peel-off adhesion test.Item AN AMINO ACID GRAFTED GRAPHENE OXIDE AS PROMISING MATERIAL IN POLY(UREA-FORMALDEHYDE)-EPOXY MICROCAPSULES FOR ENHANCING THE INTERFACIAL ADHESION OF EPOXY COATINGS(Asian Journal of Chemistry, 2023-02-27) Priyanka D; Nalini DNovel microencapsulated materials with superior anti-corrosion properties and improved adhesive strength on the metal substrate wereproduced by emulsion polymerization and characterized successfully. Initially, serine grafted graphene oxide was prepared and characterizedthrough various sophisticated techniques. Then, MC-GO/epoxy and MC-GO-Ser were individually impregnated into th epoxy systemand applied on the mild steel substrates. Corrosion tests were performed to evaluate the non-corrosive nature of MC-GO/epoxy and MC-GO-Ser/epoxy samples. After 7 days of exposure in saline media, MC-GO-Ser microcapsules demonstrated 80.6 % protective efficiency.Furthermore, the peel strength of 2.90 N revealed that the coating loaded with MC-GO-Ser microcapsules had improved adherence to themild steel surface. Results of urea-formaldehyde GO-Ser microcapsules showed better corrosion protection and greater adhesive strength,which is probably because of the exceptional barrier action of microcapsules against the incursion of corrosion solution onto the mild steelsurface