Preparation and Perfomance of an Aging-Resistant Nanocomposite Film of Binary Natural Polymer–Graphene Oxide

As one of the materials having a bionic structure, nacrelike layered composites, inspired by their natural hybrid structures, have been studied via a variety of approaches. Graphene oxide (GO), which differed from inert graphene, was used as a new building block because it could be readily chemically functionalized. Rather than natural polymers, synthetic polymers were most commonly used to fabricate nacrelike GO–polymer materials. However, naturally occurring polymers complied more easily with the requirements of biocompatibility, biodegradability, and nontoxicity. Here, a simple solution-casting method was used to mimic natural nacre and fabricate a self-assembled and aging-resistant binary natural polymer, (κ-carrageenan (κ-CAR)–Konjac glucomannan (KGM))–GO nanocomposites, with varying GO concentrations. The investigation results revealed that κ-CAR–KGM and GO mostly self-assemble via the formation of intermolecular hydrogen bonds to form a well-defined layered structure. The mechanical properties of the natural polymer–GO films were improved significantly compared to those of pure natural polymer films. With the addition of 7.5 wt % GO, the tensile strength (TS) and Young’s modulus were found to increase by 129.5 and 491.5%, respectively. In addition, the composite films demonstrated high reliability and aging resistance as well as a definite TS after cold and hot shock and ozone aging tests, especially showing a superior ozone resistance. The composite films can potentially be used as biomaterials or packing materials

Plasmonic Coupling Effect in Silver Spongelike Networks Nanoantenna for Large Increases of Surface Enhanced Raman Scattering

The electric field enhancement of the silver spongelike networks has been described to be a systematic investigation by using three-dimensional finite-difference time-domain (3D-FDTD) simulation. Surface enhanced Raman scattering (SERS) measurements have indicated that the junction regions, the hollow nanostructured, and the sharp nanotips of the broken ligaments in the silver spongelike networks act as electromagnetic “hot-spots”. The 3D-FDTD calculations have indicated that the silver spongelike networks may exhibit a high quality SERS characteristic because of the Ag chain length, chain diameters, chains gap, chains angle, and sharp nanotips. A maximum enhancement factor of 3.5 × 10¹² can be obtained with the silver spongelike networks. As potential nanoantennas, silver spongelike networks can offer an effective method to optimize plasmon coupling for synthesizing devices