Summary: A series of polyimide/ZnO nanohybrid films with different ZnO content were prepared from a rigid pyromellitic dianhydride‐4,4′‐diaminodiphenyl ether (PMDA‐ODA) polyimide (PI) and a flexible 3,3′,4,4′‐benzophenonetetracarboxylic acid dianhydride‐4,4′‐diaminodiphenyl ether (BTDA‐ODA) PI with ZnO nanoparticles (3–4 nm). Fourier‐transform infrared (FT‐IR) and X‐ray photoelectron spectroscopy (XPS) depict that the ZnO nanoparticles function as a physical cross‐linking agent with PI through hydrogen bonding between the OH on the ZnO nanoparticles and the CO of the imide groups. ZnO nanoparticles in the rigid PMDA‐ODA matrix cause a larger percentage decrease in the coefficient of linear thermal expansion (CTE) than in the flexible BTDA‐ODA matrix. The BTDA‐ODA/ZnO hybrid films have two transition peaks in dynamic mechanical tan δ curves, but PMDA‐ODA/ZnO hybrid films only have one transition peak. Thermogravimetric analysis reveals that ZnO decreases the thermal degradation temperature (Td) in both hybrid films, but less so in PMDA‐ODA/ZnO films. Transmission electron microscopy (TEM) images reveal that the rigid matrix induces larger particle size (30–40 nm) compared to the flexible matrix (10–15 nm).Illustration of the interaction between ZnO nanoparticles and PI.magnified imageIllustration of the interaction between ZnO nanoparticles and PI.

No abstract

A simple and efficient method for the in situ fabrication at ambient temperature of nanocables consisting of a silver core and an insulating organic shell from a self-assembling silver precursor is presented. The precursor assembles into tubular aggregates several microns in length, which template the formation of silver wires, under defined reaction conditions. Proper control of the reaction conditions, such as reagent concentrations and the method of reduction, is important in order to obtain well-defined nanocables as individual dispersed entities. These consist of 30-45 nm silver cores, 60-70 nm walls, and an aspect ratio of .200. IR spectroscopy revealed the organic sheath to be cross-linked via a bridging-type coordination to the silver ions, which helps in the formation of the tubular aggregation and provides structural rigidity.

No abstract

No abstract