Gopiraman Mayakrishnan

National University Corporation Shinshu University · Interdisciplinary Cluster for Cutting Edge Research (ICCER)

In recent years, biopolymer coatings have emerged as an effective approach for extending the shelf life of edible fruits. The invention of biopolymer coverings has emerged as an innovation for extending fruit shelf life. Natural polymers, like chitosan, alginate, and pectin, are used to create these surfaces, which have several uses, including crea...

Surface area, pore properties, synergistic behavior, homogenous dispersion, and interactions between carbon matrix and metal‐nanostructures are the key factors for achieving the better performance of carbon‐metal based (electro)catalysts. However, the traditional hydro‐ or solvothermal preparation of (electro)catalysts, particularly, bi‐ or tri‐met...

The research project focuses on conducting an in vitro comparison between sodium alginate and chitosan electrospun nanofibers for moist wound management. These fabricated nanofibers were incorporated with levofloxacin (Lev) as a model drug to investigate their release behavior. The study included a comprehensive examination of the physicochemical,...

Owing to the robust scalability, ease of control and substantial industrial applications, the utilization of electrospinning technology to produce piezoelectric nanofiber materials demonstrates a significant potential in the development of wearable products including flexible wearable sensors. However, it is unfortunate that the attainment of high-...

Herein, for the very first time, we report a paper-like biomass, eggshell membrane (ESM), as a suitable platform for the fabrication of a colorimetric sensor (E-Cot). Green ethanolic extract, curcumin (CUR), was used as a sensing material to coat with the ESM. The present E-Cot effectively changed its color (yellow to red) in the real-time monitori...

Smart colorimetric sensor for the naked-eye detection of food freshness is considered the most attractive tool in food safety. Herein, we prepared curcumin (CUR) coated electrospun regenerated cellulose nanofiber (RCA) composites (CUR-Cot), to monitor the real-time spoilage of raw chicken. The physicochemical properties of the CUR-Cot sensor were c...

This study was undertaken to synthesize and characterize PVDF/CB (polyvinylidene fluoride/carbon block) nanofiber composites for flexible, wearable electronic applications. Nanofibers were produced by electrospinning method and used to produce thin films. Fiber surface morphologies were investigated by FE-SEM and HR-TEM, crystalline structures by F...

The present review article discusses the elementary concepts of the sensor mechanism and various types of materials used for sensor applications. The electrospinning method is the most comfortable method to prepare the device-like structure by means of forming from the fiber structure. Though there are various materials available for sensors, the i...

Recent energy research focuses on the efficiency enhancement of supercapacitor devices for multipurpose applications. Several materials have been used as electrode materials to achieve the maximum specific capacitance. The present review article concludes with three different types of materials recently used to enhance the efficiency of supercapaci...

The present review article concludes with three different types of materials recently used to enhance the efficiency of supercapacitors. The first type involves carbon-based materials for storage and supercapacitor applications. The carbon materials could be obtained naturally and synthesized manually based on the needs. The second type discusses t...

Designing freestanding electrodes for supercapacitors has attracted tremendous attention since avoiding the use of inactive additives is cost-effective and process-efficient for the industrialization and commercialization of supercapacitors. To accommodate the vigorous electrochemical process and facilitate charge transfer, robust and conductive ba...

This study reports the effects of a robust bilayer nonwoven/nanofiber fabric comprising layers of a polyethylene terephthalate (PET) microfiber with a poly(vinylidene fluoride) (PVDF) nanofiber, fabricated by an electrospinning method, as a substrate for solid polymer electrolytes (SPEs). The substrate reinforces mechanical/thermal stability and ph...

We fabricated Zein/polycaprolactone (PCL) electrospun nanofiber sheets incorporated with different concentrations of β-caryophyllene loaded into halloysite (HNT) nanotubes as an eco-friendly, bioactive food packaging material. We obtained heterogeneous fibers with ribbon-like morphology. The loading of β-caryophyllene/HNT increased the fiber diamet...

The use of artificial biomaterial with enhanced bioactivity for osteostimulation is a major research concern at present days. In this research, antibacterial and osteostimulative core-shell lignin nanoparticles (LgNP) were synthesized from alkali lignin using tetrahydrofuran (THF) as solvent via a simultaneous pH and solvent shifting technology. La...

Electrospun nanofiber composites derived from polyurethane (PU) or polyethylene oxide (PEO) have demonstrated astonishing usability in various domestic and industrial sectors. Indeed, compositing the PU and PEO could find a...

Wound healing is a complicated process with overlapping stages, and a suitable supporting environment is required to accelerate the healing process. The fabrication of wound dressings with antibiotic, antibacterial, and sustained drug release properties is necessary in wound care. Herein, we report the fabrication of soy protein isolate/hydroxyethy...

Functional and structural nanomaterials are emerging materials that display interesting physical and chemical properties because of their size and surface area to volume ratio. Applications for these materials include uses in removing pollutants from the environment. Looking at the current state-of-the-art as well as future trends in the use of nan...

Synthesis of a series of half-sandwich Ru(II) complexes (1-5) containing acylthiourea ligand is reported herein. All the Ru(II) complexes were well characterized by analytical and spectroscopic (UV-Vis, FT-IR, NMR and mass spectrometry) methods. Molecular structures of two (2 and 3) of the complexes were confirmed by single crystal X-ray diffractio...

Herein, we demonstrate a covalent modification of hydrazine functionalized graphene oxide (FGO-H) using a protected tert-butyl carbazate (t-boc) as an intercalating agent over the GO surface and investigated as electrode candidates for electrochemical supercapacitor applications. The resulting functionalized materials were examined by different phy...

This chapter deals with the fundamental concept of the design, synthesis, functionalization, and characterization of photosensitive carbon nanotubes (CNTs) and polymeric hybrid π-conjugated materials for commercial light-emitting diode (LED) applications. The composite materials are synthesized by the functionalization of CNTs with highly conjugate...

Advancement in the understanding of a material type is often the forerunner to the stepwise progression of a technology. Multiferroic oxides are one of the most recent classes of materials having the unique property of exhibiting mutually ferromagnetism and ferroelectricity in a single phase. These include bismuth ferrite (BiFeO3), bismuth manganit...

This study details the synthesis of gold (Au) nanoparticle-supported copper ferrite (CF) over reduced graphene oxide ([email protected]) through ultrasonication–dry synthesis techniques. The vigorous stormy mixing and acoustic cavitation acquired from the intense shock waves produced during ultrasonication can effectively irradiate the reaction con...

There is a continuous finding of suitable metal complexes for biomedical and biological applications since the discovery of cisplatin. Two biologically active complexes (2 and 3) are synthesized by using 2-chloro-benzoic acid (3,5-dichloro-2-hydroxy-benzylidene)-hydrazide (1) ligand. The ligand (1) and complexes (2 & 3) are characterized by various...

Heterogenization of homogenous catalysts on solid support has attracted tremendous attention in organic synthesis due to the key benefits of heterogenized catalysts such as easy recovery and reusability. Although a considerable number of heterogenized catalysts are available, to the best of our knowledge, there is no efficient and reusable heteroge...

Aryl nitriles are versatile compounds that can be synthesized via transition-metal-mediated cyanation of aryl halides. Most of the supported-heterogeneous catalysts are noble-metals based and there are very limited numbers of efficient non-noble metal based catalysts demonstrated for the cyanation of aryl halides. Herein, bimetallic CuNi-oxide nano...

This research work aims to identify a non-toxic, cheap, and effective greener inhibitor from Hemerocallis fulva (H. fulva) for corrosion of aluminum in a 1 M H2SO4 medium at different concentrations and temperatures. We investigated the inhibitive effect of H. fulva extract in a 1 M H2SO4 solution on aluminum using weight loss measurements with var...

Herein we report a very simple ‘mix and heat’ synthesis of very fine Rh-nanoparticles loaded carbon fullerene-C60 nanocatalyst (Rh(0)NPs/Fullerene-C60) for the very first time. The preparation method used no reducing agent and capping agent to control the morphology of nanocatalyst. Transmission electron microscopy (TEM) result confirmed the unifor...

The phytochemical components of the methanol extract of Liriope platyphylla (L. platyphylla) leaves were identified using UHPLC, and their antioxidant activities were studied. The impact of the L. platyphylla extract on the corrosion of mild steel by 1 M H2SO4 was assessed using electrochemical and gravimetric techniques. L. platyphylla exhibited c...

The rational design of highly efficient bifunctional electrocatalysts for the oxygen and hydrogen evolution reactions is still an ongoing challenge. Herein, bimetallic transition metal oxide incorporated three-dimensional (3D) nitrogen-doped graphene/carbon nanotube (CNT) conductive matrix has been developed via dry synthesis and applied as a poten...

Rhodium nanoclusters were uniformly dispersed on nano-scaled graphene platelets by a simple ‘mix and heat’ method without using any toxic reagents. Distilled water was used to obtain the homogenous dispersion of Rh-nanoclusters on graphene platelets. The morphology of the resultant catalyst (Rh(0)NCs/GNPs) was studied by means of transmission elect...

Rhodium nanoclusters were uniformly dispersed on nano-scaled graphene platelets by a simple ‘mix and heat’ method without using any toxic reagents. Distilled water was used to obtain the homogenous dispersion of Rh-nanoclusters on graphene platelets. The morphology of the resultant catalyst (Rh(0)NCs/GNPs) was studied by means of transmission elect...

Green synthesis of nanocomposites is attracted huge consideration in recent years due to its positive environmental-friendly impact. The present study reports the first bimetallic Ag-Au cellulose nanofibers composite (Ag@Au/CNCs) prepared via very simple green preparation method. Aqueous leaves extract of Moringa Oleifera was used to obtain the bim...

In this study, a very simple and highly effective mechanochemical preparation method was developed for the preparation of Ni nanoparticles supported graphene oxide (GO) nanocomposites (Ni/GO, where Ni is a composition of Ni(OH)2, NiOOH, NiO, Ni2O3 and NiO2), 3 wt% NiO/GO (Ni/GO-1) and 8 wt% NiO/GO(Ni/GO-2). The developed method is not only very sim...

Cu-containing activated carbon (eco-catalyst, Cu/HMPC, where ‘C’ defines ‘carbon’) was derived from a metal-hyperaccumulating mustard plant (HMP) by a simple chemical activation method. Transmission electron microscopy/selected area diffraction (HRTEM/SAED) results revealed that the Cu/HMPC has mainly three types of morphology [sheet-like morpholog...

Highly active metal nanoparticle (MNP) supported cellulose nanofiber (CNF) composites (Au/CNF, Ni/CNF and Ag/CNF) were prepared for the reduction of 4- and 2-nitrophenols (4-NP and 2-NP) in water. Transmission electron microscopy (TEM) images showed that the ultrafine nanoparticles (Au, Ni and Ag NPs) were uniformly deposited on CNFs surface. The c...

Highly efficient nanocomposites (Ag/HHP and Ru/HHP) of Ag and Ru nanoparticles (NPs) supported on human hair powder (HHP) were prepared for reduction of 4-nitrophenol (4-NP) to 4-aminophenol. Ag/HHP and Ru/HHP worked well for reduction of 4-NP with faster reaction rate, exhibiting best rate constant (kapp) of 5.94 × 10−2 s−1 and 6.12 × 10−2 s−1, re...

Highly efficient and cost-effective NiO-based carbon nanocomposite (NiO/CNP) was prepared for the transfer hydrogenation of aromatic aldehydes and reduction of nitrophenols. Uniform dispersion of NiO nanoparticles, surface area of NiO/CNP (67m² g⁻¹), chemical state and content of Ni in NiO/CNP (+2, 5.1wt%) were confirmed. High rate constant (kapp)...

Herein, we report a highly efficient and cost-effective copper-oxide/carbon-nanoparticles catalyst (CuO/CNP) prepared by a simple 'mix and heating' method for the self-coupling of amines. Homogenous dispersion of CuO nanoparticles on the surface of CNP, +2 chemical state of Cu in CuO/CNP, 6.1 wt% of Cu in CuO/CNP, and specific surface area of CuO/C...

Interconnected meso/microporous activated carbons were prepared from pumpkin seeds using a simple chemical activation method. The porous carbon materials were prepared at different temperatures (PS-600, PS-700, PS-800, and PS-900) and demonstrated huge surface areas (645–2029 m² g–1) with excellent pore volumes (0.27–1.30 cm³ g–1). The well-condens...

Hierarchically porous carbon nanosheets (HPCN-700) were derived from human hair by a simple chemical activation method. Two-dimensional (2D) sheet-like morphology of HPCN-700 with good porosity was depicted by transmission electron microscopy. Raman and X-ray diffraction studies show that the HPCN-700 has more defect sites. The presence of heteroat...

Novel nanocatalysts (Ni/HHP and Ru/HHP) were prepared by a very simple chemical reduction method. Fine human hair powder (HHp) was obtained from raw human hair (HH) by ball milling method. Readily leachable constituents were removed from HHp to obtain HHP. The HHP was employed as support for the decoration Ni and Ru nanoparticles (NPs). Strong inte...

Human hair powder (HHP) after chemical treatment (e-HHP) has been successfully utilized as unique catalyst support for immobilization of metal nanoparticles (MNPs). Ag, Au, Cu, Ni and Ru NPs were preferred to prepare five different nanocatalysts (MNPs/e-HHP). HRTEM results confirmed the excellent attachment of ultrafine MNPs on the surface of e-HHP...

Highly porous carbon nanoarchitectures (HPCNs) were derived from biomass materials, namely, corn fibers (CF), corn leafs (CL), and corn cobs (CC). We surprisingly found that by a very simple activation process the CF, CL, and CC materials can be transformed into exciting two-dimensional (2D) and three-dimensional (3D) carbon nanoarchitectures with...

Metal- and solvent-free industrial-quality graphene oxide (IQGO) based highly efficient carbocatalytic system has been developed for the synthesis of β-ketoenamines. Initially, physicochemical properties of IQGO are briefly discussed by means of various microscopic and spectroscopic techniques. The present system accessed a wide range of substrates...

The novel method, handspinning (HS), was invented by mimicking commonly observed methods in our daily lives. The use of HS allows us to fabricate carbon nanotube-reinforced nanofibers (CNT-reinforced nanofibers) by addressing three significant challenges: (i) the difficulty of forming nanofibers at high concentrations of CNTs, (ii) aggregation of t...

Herein, we report cyclodextrins (CDs)-modified regenerated cellulose nanofibers (CDs/RCNFs) as green adsorbents for the removal of toluene from wastewater. Two different methods, namely, physical mixing and chemical grafting, were opted to combine the CDs with RCNFs. The CDs with three different kinds such as α-, β-, and γ were employed. Initially,...

Interconnected ruthenium dioxide nanoparticles (RuO2NPs) anchored graphite oxide nanocatalyst (RuO2/GO) with good BET surface-area (285 m²/g) was prepared. Under feasible reaction conditions, the RuO2/GO was worked well for oxidative synthesis of imines. The RuO2/GO catalyzed a broad range of amines including less reactive aliphatic amines in good...

Correction for ‘Rhus verniciflua as a green corrosion inhibitor for mild steel in 1 M H2SO4’ by Mayakrishnan Prabakaran et al., RSC Adv., 2016, 6, 57144–57153.

Human hair (HH) has been utilized as a support for Au and Ag nanoparticles (NPs) for the very first time. Initially, a very fine human hair powder (HHP) was obtained from HH by simple ball milling method. The HHP after chemical treatment (e-HHP) was used to prepare two different nanocatalysts, Ag NPs immobilized e-HHP (Ag/HHP) and Au NPs decorated...

For the first time, the homogeneous adsorption of ethanolic extract of Jacaranda mimosifolia green inhibitor is evaluated for inhibition of steel corrosion in acid environment. The inhibitive properties are evaluated by means of weight loss measurements, polarization studies, and electrochemical impedance spectroscopy. A maximum of 96% of inhibitio...

Herein we report successful synthesis of silk fibroin (SF) three dimensional scaffolds (SF 3D-scaffold) from SF sponge and SF nanofibers. Both the nanofibers and sponge were prepared from Bombyx mori fibroin. The SF 3D-scaffold was prepared by electrospinning the fibroin nanofibers over the sponge. Surface morphology was determined by scanning elec...

Gold nanorods (AuNRs) and silver nanoparticles (AgNPs) were fastened over single layer graphene (SLG) and successfully designated using microscopic (TEM and SEM–EDX) and spectroscopic (Raman, XRD, XPS and ICP) techniques. Salmon milt DNA stabilized the AgNPs and was also obliging in producing AuNRs. Bimetallic nanocatalyst (Au–Ag/SLG) was tremendou...

Herein, we report a comparative study of silver coated anionic cellulose nanocomposite before (CMC-Ag) and after (AgNPs/CMC) chemical reduction for antibacterial activity. Cellulose nanofibers were prepared by deacetylation of electrospun cellulose acetate nanofibers, which were then treated with sodium chloroacetate to prepare anionic cellulose na...

Herein, we report a new and simple method for the preparation of metallic copper nanospheres-decorated cellulose nanofiber composite (CuNSs/CNFs). Initially, the cellulose acetate nanofibers (CANFs) were electrospun followed by deacetylation and anionization to produce functional anionic cellulose nanofibers (f-CNFs). The CuCl2 precursor was deposi...

Herein, we report a simple and effective preparation of ultrafine CNFs (u-CNFs) with high surface area via electrospinning of two immiscible polymers [polyacrylonitrile (PAN) and poly(methyl methacrylate) (PMMA)] followed by calcination at high temperature in an inert atmosphere. Various electrospinning conditions were optimized in detail. Four dif...

The development of biocompatible nanocomposites for biomedical applications such as drug release has attracted increasing attention in recent years. We report porous silica nanoparticles (PSNs) immobilized polycaprolactone (PCL) nanofiber composites (PCL/PSNs) for drug delivery applications. The allantoin (model drug)-loaded PSNs were mixed well wi...

The methanolic extract of the plant Rhus verniciflua was examined as a corrosion inhibitor for mild steel in 1 M H2SO4 through weight loss measurements, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, electrochemical impedance spectroscopy, and potentiodynamic polarization measurements. The sample surface morphology was a...

Although polyacrylonitrile (PAN) has excellent properties as a precursor of carbon fibre, octa-amic polyhedral oligomeric silsesquioxane (POSS) nanoparticles which are hybrid organic–inorganic materials can be incorporated into PAN to tune up the properties such as the mechanical strength, thermal conductivity, and electronic conductivity for a bro...

Bio-waste material, human hair, was used as a source to prepare activated carbon (ACs) by a simple NaOH activation method. MnO2 with a needle like structure was successfully decorated on ACs by a wet impregnation method. TEM images confirmed the needle-like morphology of MnO2 on ACs. The chemical state of Mn in MnO2/ACs was found to be +4, as confi...