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A new, low-cost, and direct green synthesis strategy was developed for the preparation of polymer composites composed of silver nanoparticles (AgNPs) decorated on a shape memory polymer blend using Rubus caesius L. leaves. X-ray powder diffraction, ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy, and energy dispersive X-ray spectroscopy (EDS) elemental composition were applied to characterize the crystal size, morphology, and elemental composition of Ag-NPs. UV-vis spectra detected the characteristic absorbance signal of AgNPs at about 430 nm, and the average crystal size of nanoparticles was calculated as about 12.60 nm. When nanocomposite films were characterized by attenuated total reflectance infrared spectroscopy, characteristic polylactic acid, and poly ethylene glycol (PEG) signals were determined. From the thermogravimetric analysis curves, it was determined that the amount of residue of nanocomposites increased as the amount of AgNP increased. It was seen that AgNPs did not affect the [T.sub.g] temperature of the nanocomposite films, while it was also a proof that the polymer blend was immiscible. It was observed that the shape recovery properties of nanocomposite films were better with increasing AgNPs content. Finally, both green synthesized AgNPs and nanocomposites prepared with shape memory polymers showed very good antibacterial activity against Gram-positive and Gram- negative bacteria. Highlights * Green synthesis of silver nanoparticles (AgNPs) was carried out with Rubus caesius L. leaves. * The synthesized AgNPs were characterized by ultraviolet visible spectroscopy and x-ray powder diffraction. * Composite films were prepared with poly lactic acid/poly [epsilon]- caprolactone blend by solvent casting method. * The amount of residue of nanocomposites increased with increasing AgNPs percentage. * The nanocomposite film containing 10% AgNPs has good activity. KEYWORDS antibacterial, green synthesis silver nanoparticles, nanocomposite, poly [epsilon]-caprolactone, poly lactic acid, shape memory effect, 1 | INTRODUCTION Nanoscale materials ranging from 1 to 100 nm are thought to provide solutions to environmental and technological challenges in medicine and water treatment. (1,2) This increasing demand [...]

Tunable hydrogel that contained well-defined poly(vinyl alcohol) (PVA), labile lactate groups, and hydrophilic poly(ethylene glycol) (PEG) segments was prepared through a combination of reversible addition-fragmentation chain transfer (RAFT) polymerization and esterification reaction. A diol was prepared via the esterification between lactic acid (LA) and PEG. Then the diol was allowed to react with maleic anhydride to produce a diacid. Meanwhile, well-defined PVA was synthesized by the alcoholysis of poly(vinyl acetate) (PVAc) obtained by RAFT polymerization of vinyl acetate. The hydrogels with tailor-made structure were generated by crosslinking PVA with LA-based diacid. The structures and properties of LA-based intermediates and the hydrogels were characterized with Fourier transform infrared spectroscopy, gel permeation chromatography, differential scanning calorimetry, and thermogravimetric analysis. Both LA-based diol and diacid were semicrystalline and water-soluble, their melting temperature and glass transition temperature were 52 and -51, 54 and -41°C, respectively. The polydispersity indexes of the precursor of PVA samples were within the range of 1.03-1.10. It was found that the thermal stability of hydrogel was higher than that of LA-based diacid. Both the swelling and release properties of the hydrogels depend on the feeding ratio of PVA/LEM and the chain length of PVA, which reflected that the structure and properties of the hydrogels were controllable., INTRODUCTION Owing to the advantages such as nontoxic, biocompatible, excellent mechanical and physicochemical properties, biodegradable hydrogels are regarded as suitable materials for biomedical, pharmaceutical, environmental, and other applications [1-3]. The [...]

As a typical smart material, ionic polymer metal composite (IPMC) has a sandwich structure, which consists of a base membrane and two thin metallic electrodes on both sides of the [...]

Boron is widely used in various areas of people activity; it belongs to elements playing an important role in biosphere. Its excessive accumulation in the environment and insufficiency are equally [...], The conditions for the thermal lens quantification of boron in aqueous solutions with a detection limit of 0.3 ng/mL are found (λ = 532 nm, laser power 40 mW); this value of the detection limit is an order of magnitude lower than that attainable in conventional spectrophotometry. A 1 : 1 composition of an aqueous ethylene glycol mixture is proposed, using which as a medium the detection limit for boron was reduced to 0.1 ng/mL. Using spectrophotometry and thermal lens spectrometry, boron was quantified in mineral water; the results agree with the data acquired by the reference method of inductively coupled plasma atomic emission spectrometry. Keywords: thermal lens spectrometry, boron, mixed media, water analysis.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.solener.2008.12.009 Byline: Todd P. Otanicar (a), Patrick E. Phelan (a), Jay S. Golden (b)(c) Keywords: Optical properties; Fluids; Solar thermal energy Abstract: A method for experimentally determining the extinction index of four liquids (water, ethylene glycol, propylene glycol, and Therminol VP-1) commonly used in solar thermal energy applications was developed. In addition to the extinction index, we report the refractive indices available within the literature for these four fluids. The final value reported is the solar-weighted absorption coefficient for the fluids demonstrating each fluid's baseline capacity for absorbing solar energy. Water is shown to be the best absorber of solar energy of the four fluids, but it is still a weak absorber, only absorbing 13% of the energy. These values represent the baseline potential for a fluid to be utilized in a direct absorption solar thermal collector. Author Affiliation: (a) Department of Mechanical and Aerospace Engineering, National Center of Excellence on SMART Innovations, Arizona State University, P.O. Box 876106, Tempe, AZ 85287-6106, USA (b) Department of Civil and Environmental Engineering, National Center of Excellence on SMART Innovations, Arizona State University, P.O. Box 876106, Tempe, AZ 85287-6106, USA (c) School of Sustainability, National Center of Excellence on SMART Innovations, Arizona State University, P.O. Box 876106, Tempe, AZ 85287-6106, USA Article History: Received 2 June 2008; Revised 25 November 2008; Accepted 21 December 2008 Article Note: (miscellaneous) Communicated by: Associate Editor Darren Bagnall

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2005.08.015 Byline: Cheikh Fall, Felipe M. Cuenca, Khalidou M. BAcents, Carlos M. Solis Abstract: This paper focuses on environmental concerns regarding used antifreeze. It shows the results of laboratory respirometric tests conducted to evaluate the potential impact of antifreeze on activated sludge. In this first step of the study, only the components of virgin antifreeze were addressed, i.e. ethylene glycol, and antifoaming and corrosion inhibitory substances. The plateau resulting from oxygen uptake rate measurements of mixed liquor taken at the end of an aeration tank is used as a reference to evaluate the response of biomass to pulse injection of increasing dosages of new antifreeze, compared to that of formaldehyde, a known toxic compound. While 200mg/L of formaldehyde steadily decreased the biomass activity (7mg O.sub.2/Lh), there were no toxicity effects for doses up to 5000mg/L of ethylene glycol from new antifreeze coolant (23mg O.sub.2/Lh, compared to the initial 15mg O.sub.2/Lh for the mixed liquor). It is estimated that ethylene glycol concentration in municipal wastewaters should be several order of magnitude lower then the 1000mg/L shown to be tolerated by the biomass in this work, but at the present stage, the research does not provide enough information to recommend a definitive management scheme for antifreeze discharge. Many other management issues for used antifreeze must be addressed in future studies before any decision on tolerating sewer discharge in Mexico, as a transitory management option that will conciliate the actual practices with legality, can be made. Author Affiliation: Universidad Autonoma del Estado de Mexico, Centro Interamericano de Recursos del Agua, Apartado Postal 367, Toluca, C.P. 50091 Estado de Mexico, Mexico Article History: Received 19 July 2004; Revised 23 August 2005; Accepted 26 August 2005

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.solener.2005.04.013 Byline: A.V. Kokate, U.B. Suryavanshi, C.H. Bhosale Keywords: Electrodeposition; CdSe thin films; PEC characterization; Optical absorption Abstract: In the recent years, cadmium chalcogenide compounds have been extensively investigated because of their potential applications in solar energy conversion. Thin films of CdSe have been deposited onto the stainless steel and fluorine doped tin oxide (FTO) coated glass substrates using simple and inexpensive electrodeposition technique. The non-aqueous solvent ethylene glycol (CH.sub.2OHCH.sub.2OH) containing precursors of Cd and Se with ethylenediaminetetraacetic acid (EDTA) tetra sodium salt as a complexing agent is used to obtain stoichiometric deposits. Deposition potential was estimated from polarization curves and other preparative parameters such as bath temperature and concentration of solution were optimized. X-ray diffraction (XRD) analysis reveals that the films are polycrystalline with cubic structure. PEC study shows the CdSe films are photoactive. Optical absorption study shows the presence of direct transition with band gap energy 1.72eV. The energy dispersive analysis by X-rays (EDAX) reveals that the substrate is well covered with large number of grains indicating compact structure. The average ratio of the atomic percentage of Cd:Se is 50.31:49.69, showing that the deposited films are almost stoichiometric. Author Affiliation: Electrochemical Materials Research Laboratory, Department of Physics, Shivaji University, Kolhapur 416 004, India Article History: Received 1 November 2004; Revised 20 April 2005; Accepted 25 April 2005 Article Note: (miscellaneous) Communicated by: Associate Editor Xavier Matthew

The thermal conductivity and viscosity of various shapes of alumina nanoparticles in a fluid consisting of equal volumes of ethylene glycol and water are examined. The efficiency of nanofluids for real-life cooling applications is analyzed in both the laminar and tubular flow regimes by using the experimental values of thermal conductivity and viscosity.

Homogenous ice nucleation temperatures (TH) of aqueous solutions of methanol, ethylene glycol, glycerol, xylitol, poly(ethylene glycol)s, glucose, and fructose are measured as a function of solute concentration. Through experimental data, it is shown that the magnitude of TH depends strongly on the nature of the solute.