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The current work focuses on the incorporation of excess amount of gallium (Ga) in zinc oxide (ZnO) nanowires to generate oxygen interstitials for developing p-type conductivity. Ga has been used as an n-type dopant in ZnO lattice by reducing its inherent vacancies up to 3% molar ratio of Ga and Zn employing chemical bath deposition technique. However, the addition of more than 4% of gallium nitrate in the bath solution creates oxygen interstitials which are confirmed from the presence of X-ray photoelectron spectroscopy (XPS) peak at 532.6 eV and the relevant cathodoluminescence (CL) peak at 626 nm of the grown Ga-doped ZnO nanowires. The p-type conductivity of such ZnO nanowires has been confirmed from current–voltage, capacitance–voltage and Hall voltage measurements. The reproducibility of the results indicates the incorporation of excess Ga to be a promising technique for growing p-type ZnO nanowires.

Ag-Ag2S core-shell nano-structured particles, prepared by soft chemical route, were found to be luminescent in the near-infrared (NIR) range. The silver nanoparticles were pre-synthesized with size control by poly-vinyl-pyrrolidone (PVP) polymer capping from silver nitrate solution, by reduction using sodium borohydride in solution, which were further subjected to reaction with sulfur ions in the later stage by mixing controlled amount of Na2S in the solution. With increasing concentration of sulfur ions, the plasmonic peak of Ag showed progressive blue shift and damping, leading to final diminishment. Enhanced NIR luminescence obtained from Ag@Ag2S core-shell nanoparticles were found to be asymmetric and blue shifting with reduced intensity and increasing sulfur ion concentration. The mechanism behind such a behavior is predicted due to formation of composite layer of Ag2S-Ag both at the surface and the volume, with Ag core at the center, diminishing in size with increasing sulfur concentration. The structure, chemical composition, morphology and final core-shell structure formation were further established by combination of X-ray diffractometry (XRD), X-ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM) analysis.

Bacteria endogenously residing within the plant tissues have attracted significant attention for production of biopolyester, polyhydroxyalkanoates (PHAs). Bacillus cereus RCL 02 (MCC 3436), a leaf endophyte of oleaginous plant Ricinus communis L. accumulates 81% poly(3-hydroxybutyrate) [P(3HB)] of its cell dry biomass when grown in mineral salts (MS) medium. The copolymer production efficiency of B. cereus RCL 02 was evaluated in valeric acid supplemented MS medium under biphasic cultivation condition. The copolymer so produced has been compared with the P(3HB) isolated from RCL 02 in terms of thermal, mechanical and chemical properties. Valeric acid supplementation as co-substrate in the medium has led to the production of copolymer of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) [P(3HB-co-3HV)] with 14.6 mol% 3HV. The identity of the polymers has been confirmed by X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopic studies. Thermogravimetric analysis (TGA) revealed that P(3HB) and P(3HB-co-3HV) films degraded at 278.66°C and 273.49°C, respectively. The P(3HB-co-3HV) showed lower melting temperature (165.03°C) compared to P (3HB) (170.74°C) according to differential scanning calorimetry (DSC). Incorporation of 3HV monomers decreased the tensile strength (21.52 MPa), tensile modulus (0.93 GPa), storage modulus (E′) (0.99 GPa) and increased % elongation at break (12.2%) of the copolyester. However, P(3HB) showed better barrier properties with lower water vapor transmission rate (WVTR) of 0.55 g-mil/100 in2/24 h. These findings emphasized exploration of endophytic bacterial strain (RCL 02) to produce biodegradable polyesters which might have significant potential for industrial application.

Non-toxic nanocomposites based bio-films obtained from methylcellulose (MC) can reduce environmental problems associated with synthetic polymers. A new facile route for the isolation of cellulose nano-crystals (CNC) from jute waste is successfully utilized here. The fabrication of CNC reinforced MC nanocomposites by film casting technique and the studies of the effect of CNC on the properties of the MC based nanocomposites have been reported. The synthesized nanocomposites have shown improved UV resistance, mechanical, barrier, and thermal properties. FTIR results established the physicochemical compatibility between the drug, MC and CNC in nanocomposites. In vitro permeation studies performed by using Franz diffusion cell revealed diffusion mediated sustained drug release from the devices due to the presence of interaction between MC and CNC through H-bonding, electrostatic interaction between the hydrophilic polymer/CNC chains with the drug and the formation of tortuous path. The nanocomposites can be used for edible packaging and transdermal drug delivery.

There is a need for reuse of waste cotton lint (WCL) from the blow room of yarn spinning mills. The drive to use this material for the synthesis of nanocellulose is difficult because of the several purification/pretreatment processes. Here, we developed a combined single bath purification process of WCL and utilized it for the synthesis of nano-crystalline cellulose crystals (NCs) which are valuable nanomaterials with novel properties along with acid recovery for reuse. The micrograph of the synthesized NCs confirmed a network of nano-sized crystalline cellulose crystals having nano ranged diameter of NCs isolated by two processes. The FTIR result established the removal of impurities and hemicelluloses from WCL. The crystallinity index of WCL (∼89.97%) is improved to ∼96% and ∼94% for sulphuric acid and nitric acid synthesized NCs (NC1 and NC2). The crystallite size of WCL, CTWCL, NC1, and NC2 was calculated using XRD and found to be 101.56, 103.54, 98.81, and 95.6nm respectively. The hydrodynamic size (Z-average) (dnm), polydispersity index and zeta potential of NCs was also studied using dynamic light scattering (DLS). The thermal stability of the NC1 is better than that of NC2. These NCs can be used as reinforcing filler/barrier material.

ZnO nanowires/p-Si heterojunction diodes are fabricated by employing low temperature double-step chemical bath deposition technique. The grown samples are initially annealed at different temperatures in the range of 300 °C to 600 °C at 10 psi argon atmosphere for 30 min. Field emission scanning electron microscope images confirmed the growth of vertically oriented ZnO nanowires with average nanowire diameter and height of 183–190 nm and ~1.4 μm, respectively. The x-ray diffraction study shows that the samples are poly-crystalline with hexagonal wurtzite structure and ZnO nanowires are vertically c-axis oriented. The photoluminescence study indicates the presence of oxygen vacancy in as-grown and 300 °C annealed sample, whereas, the 500 °C annealed ZnO nanowires show the existence of oxygen interstitials. Heterojunction diodes are fabricated on the as-grown, 300 °C, 400 °C, 450 °C, 460 °C, 475 °C, 490 °C, 500 °C, 550 °C and 600 °C annealed nanowires for the measurements of current-voltage and capacitance-voltage characteristics. Both the results indicate an electron dominated transport for the as-grown to 490 °C samples and hole transport for ≥500 °C annealed sample. The acceptor or p-type dopant formation temperature is observed to be 500 °C, which shows an effective acceptor concentration of 1.15 × 1015 cm−3 (at 10 kHz) and 1.74 × 1015 cm−3 (at 1 MHz). Thus the work indicates a possible route for converting the n-type ZnO nanowires to p-type of nature.

Nowadays, bio-derived cellulose nano-fibrils based nanocomposites is gaining utmost interest in the area of barrier films for food packaging, as reinforcing filler to make biodegradable nanocomposites with different biopolymers for various applications such as transdermal drug delivery, edible packaging and tissue scaffolding. Ultrasound-assisted preparation of hydroxypropylmethylcellulose based nanocomposites with cellulose nano-fibrils were carried out following solution mixing technique. The crystalline nature of cellulose nano-fibrils has been scrutinized by X-ray diffraction study. The field emission-scanning electron micrographs of cellulose nano-fibrils revealed a network of nano-fibrillar morphology. The Fourier transform infrared spectroscopy results of cellulose nano-fibrils confirmed the removal of lignin and hemicellulose from raw jute (Corchorus olitorius L.) fibres. The storage modulus and tensile properties of hydroxypropyl methylcellulose films increased up to the addition of 1.00 wt% cellulose nano-fibrils. The moisture affinity of hydrophilic hydroxypropylmethylcellulose has also been reduced at 1.00 wt% cellulose nano-fibrils loading. The impact of cellulose nano-fibrils loading on the cumulative percentage of drug release from prepared nanocomposites films has been explored accordingly. By utilizing these versatilities of cellulose nano-fibrils, the fabricated nanocomposites are expected to be highly promising in the area of packaging and transdermal drug delivery system.

Proflavine, a nitrogen-containing dye is used for DNA staining and as an efficient marker, however, it is harmful to body cells, and its efficient removal is essential. In this work, graphene oxide (GO) has been used as an adsorbent for the removal of the dye through the process of adsorption. Though GO is now being used as an adsorbent for the removal of industrial dyes, very few experiments have been done on biologically useful dyes. GO is synthesized from graphite powder by the modified Hummer's method and is characterized by X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), Raman and ultra-violet spectroscopies, etc. These characterization techniques indicate the presence of oxygen containing functional groups, e.g., carbonyl, carboxyl and hydroxyl groups on the graphene sheets. These sheets are held well apart by these groups. Parameters like concentration of the adsorbent, pH and temperature have been varied to find the optimum conditions for the most efficient removal of the dye molecules from the solution. Then, for the optimum external conditions, the time dependence of the adsorption was analyzed using pseudo-first and pseudo-second orders kinetics. The adsorption isotherms were also obtaining throws light on the mechanism of the adsorption process which we investigated further by using FTIR characterization.

A nanocomposite of activated carbon (AC) and graphene oxide (GO) has been used as adsorbent of methylene blue (MB) dye from solution. FTIR spectroscopy, XRD, SEM imaging, size and zeta potential analysis of the nanocomposite material indicate retention of the essential features of both the components responsible for adsorption. Parameters like pH, temperature, adsorbent and salt concentrations, etc. were varied to optimize the adsorption. A very significant increase in adsorption by this nanocomposite, compared to those arising from the individual components, could be observed, resulting in an adsorption capacity of up to 1000 mg/gm. Fit of the data to kinetic equations gave rate constants for the process. Good fits to both Langmuir and Freundlisch isotherms indicated that the contribution of electrostatic attraction between the charged groups present in the composite and dye molecules, as well as the adsorption through AC surface pores both play significant roles. The synergy of these two different mechanisms yields the extraordinarily large adsorption capacity. This factor, together with the cheapness of the material, and its selectivity towards cationic dyes suggest its practical importance for water decontamination.

Cellulose nanofibrils (CNFs) have attracted attention as a promising material in the biomedical field because of their outstanding properties such as hydrophilicity, biocompatibility, biodegradability, and high surface area. In this work, we have prepared cellulose nanofibrils from jute fibres (JF), to develop a CNF/chitosan transdermal film for the delivery of ketorolec tromethamine (KT) where the CNFs act as an elegant nanometric carrier. The KT-loaded CNF/chitosan transdermal film matrices have been characterized by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. Fourier transform infrared spectroscopy (FTIR) reveals the successful KT loading into the CNF/chitosan transdermal film. Scanning electron microscopy (SEM) study shows the different morphological features of the CNF/chitosan transdermal films. The crystalline nature of the CNF/chitosan transdermal films has been analyzed by X-ray diffraction study. Release profiles from the CNF/chitosan matrices indicate that the drug release rate is sustained with the incorporation of CNFs. We believe that this new nanocarrier may be a potential choice for transdermal drug delivery systems.

This work develops a rationale for effective sensitization of trivalent lanthanide cation (Ln3+) luminescence in a semiconductor nanoparticle by examining the luminescence characteristics of Ln3+ dopants in titanium dioxide nanoparticles [Ti(Ln)O2] [Ln = praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), or ytterbium (Yb)], as a representative model system. For excitation of the TiO2 host at 350 nm the intraconfigurational 4f–4f sharp luminescence bands are observed for the Nd, Sm, Eu, Ho, Er, Tm, and Yb incorporated (doped) nanoparticles, and no such luminescence is observed for the Pr, Gd, Tb, and Dy containing nanoparticles. While host sensitized luminescence of lanthanide ions dominate the emission in the Nd and Sm incorporated nanoparticles, the host sensitization effect is less pronounced for the Eu and Yb containing systems, and for the Ho, Er, and Tm doped nanocrystals only a subset of the dopant...

In this work, the CuO nano-powder has been synthesized by employing chemical bath deposition technique for its subsequent use to grow ultrathin film (20 nm) of p-CuO on n-Si substrate for the fabrication of p-CuO/n-Si hetero-junction diodes. The thin CuO film has been grown by employing vapour-liquid-solid method. The crystalline structure and chemical phase of the film are characterized by employing field-emission scanning electron microscopy and X-ray diffraction studies. Chemical stoichiometry of the film has been confirmed by using energy dispersive X-ray spectroscopy. The potential for photovoltaic applications of such films is investigated by measuring the junction current-voltage characteristics and by extracting the relevant parameters such as open circuit photo-generated voltage, short circuit current density, fill-factor and energy conversion efficiency.

Triblock poloxamer copolymer (PM) has been extensively utilized to deliver various ophthalmic pharmaceutical compounds. The aim of efficient ophthalmic drug delivery strategy is to attain the longer precorneal resident time and good bioavailability of drugs. In this pursuit, the influence of cellulose nanocrystals (CNC) on the in situ gelation behavior of PM and in vitro release of pilocarpine hydrochloride from the nanocomposites formulations was studied. The critical concentration of gelation of PM being 18% (wt/v) was dropped to 16.6% (wt/v) by the addition of a very low percentage of CNC. The reinforcing nature of CNC via H-bonding in the in situ nanocomposite gel also led to an increase in gel strength along with the sustained release of loaded drugs when compared with the pure PM gel. All formulations revealed that the drug release mechanism is controlled by the Fickian diffusion. Thus, the CNC has a significant effect on the gelation behavior, gel strength, and drug release kinetics of PM-CNC formulations.

In this work, we report the development of a cross-linked bio-composite consisting of graphene oxide, potato starch, cross-linker glutaraldehyde and its application to adsorption of the industrial dye, methylene blue, from aqueous solution. The inexpensiveness, non-hazardous nature and easy bio-degradability are the major reasons for the selection of starch material as one of the components of the bio-composite. The bio-composite has been characterized by FTIR, SEM, XRD, particle size and zeta potential analysis. The FTIR analysis reveals the nature of the binding sites and surface morphology of the bio-composite can be understood through SEM. The auto-phase separability of the adsorbent i.e., the precipitation of the adsorbent without any mechanical means is another factor which makes this particular material very attractive as an adsorbent. Parameters like adsorbent dosage, pH, temperature, rotation speed and salt concentration have been varied to find out the suitable dye adsorption conditions. Furthermore, the time dependence of adsorption process has been analyzed using pseudo-first and pseudo-second order kinetics. The adsorption isotherms have been constructed to suggest convincing mechanistic pathway for this adsorption process. Finally, desorption studies have been successfully performed in 3 cycles, establishing the reusability of the material, which should allow the adsorbent to be economically promising for practical application in wastewater treatment.

Packaging film that possess antimicrobial activity is one of the ground-breaking concepts in food packaging. The main object of this work was to develop nontoxic nanocomposite films with good antimicrobial properties. Cellulose acetate (CA), polyethylene glycol (PEG) and cetyltrimethylammonium bromide (CTAB) modified montmorillonite (OMMT) were used to prepare the nanocomposite films. OMMT is characterized using X-ray diffraction (XRD) and Fourier transform infrared analysis. The films composed of 20 wt% PEG in a CA matrix (CP20) gave optimum results in terms of mechanical properties. OMMT (1, 3 and 5 wt%) was incorporated into the CP20 matrix to prepare the nanocomposites. XRD and transmission electron microscopy analysis showed that the nanocomposites are intercalated in nature. 3 wt% OMMT loaded nanocomposite gave the best results in terms of mechanical and barrier properties. The storage modulus and thermal stability of the nanocomposites increase with the increasing concentration of OMMT from 1–5 wt%. Optical clarity of the nanocomposites is not much affected in the visible region with different loadings of OMMT. These nanocomposites possess good antimicrobial activity as well as showing no toxicity towards human blood, so can be used as active packaging material.

Films based on methylcellulose (MC) and pectin (PEC) of different ratios were prepared. MC/PEC (90:10) (MP10) gave the best results in terms of mechanical properties. Sodium montmorillonite (MMT) (1, 3 and 5 wt%) was incorporated in the MP10 matrix. The resulting films were characterized by X-ray diffraction and transmission electron microscopy, and it was found that nanocomposites were intercalated in nature. Mechanical studies established that addition of 3 wt% MMT gave best results in terms of mechanical properties. However, thermo-gravimetric and dynamic mechanical analysis proved that decomposition and glass transition temperature increased with increasing MMT concentration from 1 to 5 wt%. It was also observed that moisture absorption and water vapor permeability studies gave best result in the case of 3 wt% MMT. Optical clarity of the nanocomposite films was not much affected with loading of MMT. In vitro drug release studies showed that MC/PEC/MMT based films can be used for controlled transdermal drug delivery applications.

This study demonstrates the electronic applications of graphene synthesized from the graphite electrode of waste dry cell zinc–carbon batteries. Graphite powder [G (R)] is successfully recovered from the graphite electrode of waste batteries by acid treatment and used as starting material for synthesis of graphene oxide (GO) following Hummers method. Finally, reduced graphene oxide (RGO) was obtained from the chemical reduction of GO by hydrazine hydrate. RGO thus obtained was characterized by X-ray diffraction, Raman spectroscopy, Fourier-transform infrared spectroscopy, UV-vis absorption spectroscopy, dynamic light scattering, energy dispersive X-ray spectra and transmission electron microscopy to get detailed information about the structure and morphology of the RGO. All the above characterization results confirmed the restoration of sp2 conjugation and removal of functional groups after the reduction of GO and also the sheet like morphology of RGO. The surface charge and stability of RGO in an aqueous medium are examined by measuring zeta potential. An electrochemical study demonstrated that, at different sweep rates, the current is the highest for RGO and lowest for GO and the current increases with an increasing sweep rate for all materials. The loop area of all the samples at the 100 mV s−1 sweep rate is the highest. The galvanostatic charging/discharging measurements have also been performed for both the GO and RGO samples at a current density of 1 mA g−1. Electro-conductivity measurement shows that RGO has higher conductivity than GO due to the restoration of the sp2 structure. The current voltage (I–V) characteristics show a non-linear behavior of GO and the ohmic nature of RGO.

Permeability characteristics of the anti-hypertensive drug, diltiazem hydrochloride, from uncross-linked and cross-linked methylcellulose (MC)/graphene oxide (GO) rate controlling membranes (RCMs) were investigated. The MC/GO membranes were cross-linked with different concentrations of glutaraldehyde (GLA) to examine the effect of cross-linking on the permeability characteristics. The ATR-FTIR spectra, along with solubility resistance, swelling studies, the molar mass between cross-links, and moisture absorption of cross-linked RCMs over the uncross-linked RCM confirmed the cross-linking between MC and GO. The cross sectional view of cross-linked and uncross-linked RCMs, as observed by SEM, showed that the porous and fibrillose structure of the uncross-linked RCM was disrupted after cross-linking. The cross-linked RCMs showed improved mechanical and thermal properties compared to the uncross-linked RCMs. In vitro and ex vivo drug release was found to depend on the concentration of the cross-linker, which suggests that drug delivery is controlled by the cross-link density of RCM.

Our research is devoted to developing a methylcellulose (MC) based in situ gelling ophthalmic formulation using pilocarpine hydrochloride as a model drug, containing different proportions of i (iota)-carrageenan and potassium chloride. This study will evaluate the utility of the proposed formulation to be a substitute for traditional eye drops. Use of both i-carrageenan and potassium chloride of definite wt% effectively reduces the gel temperature of the virgin MC solution from 60 °C to 33.5 °C which is below physiological temperature. The conventional methods like test tube tilting, and viscosity measurements are used to determine the gelation temperature while the gels are subjected to swelling as well as a gel dissolution study. Subsequently, the outcome from in vitro and in vivo studies confirms that the present system may be a better alternative compared to conventional eye drops.

This study demonstrates the physical and electrochemical characterization of nanocomposites based on reduced graphene oxide (RGO) and silver nanoparticles (Ag NPs) synthesized by adopting a green and low cost approach using lactulose as a reducing and stabilizing agent. The RGO/Ag nanocomposites were characterized by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, UV-vis absorption spectroscopy and transmission electron microscopy (TEM) to obtain clear information about the removal of functional groups and morphology of nanocomposites. XRD results confirmed the formation of a high purity crystal of Ag on RGO. FTIR results established partial reduction of GO to RGO by lactulose. TEM images show that spherical Ag NPs of an average size of 4 nm are uniformly deposited onto RGO sheets and also prevent the restacking of RGO layers. The energy dispersive X-ray spectra (EDX) of RGO/Ag nanocomposites indicate the presence of Ag and graphene. Also, EDX spectra of FESEM show that Ag content increases with the increasing concentration of AgNO3 in RGO/Ag nanocomposites. The surface charge as well as stability of the nanocomposites is examined by measuring the zeta potential while electro-conductivity is measured by potentiostat–galvanostat. The zeta potential and conductivity of RGO/Ag nanocomposites is greatly improved compared to GO and RGO. The electro-conductivity of RGO/Ag nanocomposites indicates that conductivity of RGO/Ag nanocomposite increases with increasing concentration of Ag. The electrochemical result also indicates the presence of a higher amount of ionic functional groups in GO than those in RGO and RGO/Ag nanocomposites. GO indicates the lowest current which gradually increased for RGO and RGO/Ag nanocomposites, respectively.

Active packaging is one of the interesting concepts in food industry which extend the shelf-life of the food products. The purpose of this work was to develop nontoxic antimicrobial nanocomposite films. Benzyltrimethylammonium chloride modified montmorillonite (BMMT) were used as nano-filler and the prepared BMMT was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis. Polyethylene glycol (PEG) plasticized cellulose acetate butyrate (CAB) films with different ratios of PEG and CAB was prepared and it was found that the 20 wt% PEG in CAB matrix (CBP20) gave optimal results in terms of mechanical properties. BMMT was mixed with CBP20 in different proportions to prepare nanocomposites. 3 wt% BMMT loaded nanocomposite gave best in terms of the barrier and mechanical properties. The storage modulus, thermal stability, glass transition, and melting temperature of the nanocomposites increased with the loading of 1, 3, and 5 wt% of BMMT. Furthermore, these nanocomposites showed nontoxic and antimicrobial behavior.

The present work focuses on the design of a CO2 scavenger, capable of adsorbing a low concentration of CO2 from a mixed gas composition. Typically, vinyl imidazole and an ionic liquid brancher were copolymerized by “Strathclyde methodology” and grafted from graphene oxide; GO-g-(HB) PVIm-co-PIL (Cl). The chain transfer agent maintained short chains and developed hyperbranched architecture in GO-g-(HB) PVIm-co-PIL (Cl). The structure and the properties of GO-g-(HB) PVIm-co-PIL (Cl) was established from FTIR, 1HNMR, Raman, XRD and rheology. A metathesis reaction was carried out to exchange chloride anions with hexafluorophosphate anions; GO-g-(HB) PVIm-co-PIL (PF6). GO-g-(HB) PVIm-co-PIL (PF6) selectively captured a low concentration of CO2 from a mixed gas. The surface functionalities/ properties of GO, hyperbranched architecture, porosity, nitrogen content and surface charge distribution together played a significant role in efficient and selective CO2 capture.

A reduced graphene oxide/cuprous oxide (RGO/Cu2O) nanocomposite has been successfully synthesized applying a simple in situ reduction method using an aqueous solution of lactulose which is used simultaneously as a reducing and stabilizing agent. Lactulose, a disaccharide, has the ability to reduce both GO and CuSO4 in situ under alkaline conditions. The GO and RGO/Cu2O nanocomposites are characterized using transmission electron microscopy, energy dispersive X-ray spectroscopy, field emission scanning electron spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy and UV-vis absorption spectroscopy. The surface charge as well as stability is established by analyzing the zeta potential value. The results confirm the synthesis of the RGO/Cu2O nanocomposite and the existence of interactions between Cu2O and RGO. It is also observed that Cu2O nanoparticles with an average size of 5 nm are uniformly dispersed throughout the RGO sheets. The catalytic activity of the RGO/Cu2O nanocomposite is excellent for the ‘click’ reaction and remains the same for six cycles.

A facile one-pot approach for rapid synthesis of silver and gold nanoparticles (Ag NPs and Au NPs) with narrow size distribution and good stability was described by reducing silver nitrate and chloroauric acid with polysaccharide dextrin. Here, dextrin was used as both a reducing and stabilizing agent for synthesis of NPs. The as-synthesized Ag NPs and Au NPs were characterized by UV–visible absorption spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD). The Ag NPs and Au NPs exhibited an absorption maxima at 404 and 547 nm respectively. TEM images showed NPs in the range of 8–28 nm. The crystallinity of the NPs was measured by XRD analysis. Furthermore, the as-prepared Ag NPs revealed colorimetric sensor property for detection of Cu2+ ions based on changes in absorbance resulting from metal ion-induced aggregation of NPs or direct deposition of metal ions onto NPs. The as-prepared Au NPs exhibited a notable catalytic activity toward the reduction of 4-nitrophenol to 4-aminophenol in the presence of NaBH4.

The aim of this work is to examine the effectiveness of mucilage/hydroxypropylmethylcellulose (HPMC) based transdermal patch (matrix type) as a drug delivery device. We have successfully extracted mucilage from Colocasia esculenta (Taro) corms and prepared diltiazem hydrochloride incorporated mucilage/HPMC based transdermal patches using various wt% of mucilage by the solvent evaporation technique. Characterization of both mucilage and transdermal patches has been done by several techniques such as Molisch's test, organoleptic evaluation of mucilage, mechanical, morphological and thermal analysis of transdermal patches. Skin irritation test is studied on hairless Albino rat skin showing that transdermal patches are apparently free of potentially hazardous skin irritation. Fourier transform infrared analysis shows that there is no interaction between drug, mucilage and HPMC while scanning electron microscopy shows the surface morphology of transdermal patches. In vitro drug release time of mucilage-HPMC based transdermal patches is prolonged with increasing mucilage concentration in the formulation.

Poly(butylene adipate-co-terephthalate) (PBAT) nanocomposites films are prepared by a solution intercalation process using natural montmorillonite (MMT) and cetyltrimethylammonium bromide (CTAB)-modified montmorillonite (CMMT). Cation exchange technique has been used for modification of MMT by CTAB and characterized by Fourier transform infrared analysis, thermo-gravimetric analysis, and X-ray diffraction (XRD) studies. CMMT gives better dispersion in the PBAT matrix than MMT and is confirmed by XRD and transmission electron microscopy. Because of better compatibility of CMMT, water vapor transmission rate of PBAT decreases more in the presence of CMMT than MMT. The biodegradability of PBAT and its nanocomposite films are studied in compost and from the morphological analysis it is apparent that the PBAT/CMMT shows a lower biodegradation rate in comparison to the PBAT/MMT. The antimicrobial activity of PBAT and its nanocomposite films is tested by an inhibition zone method. Because of the presence of the quaternary ammonium group of CTAB-modified MMT, PBAT/CMMT nanocomposites show adequate antimicrobial activity. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40079.