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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 [...]