Synthesis of Cu or Cu₂O-polyimide nanocomposites using Cu powders and their optical properties

Abstract

Nanocomposites consisting of Cu or Cu2O nanoparticles in various polyimide (PI) films were successfully prepared using polyamic acid (PAA) and Cu powders. Cu powders were dissolved into PAA solutions, and the solutions were spin-coated onto the substrates. Cu or Cu2O nanoparticles were formed in PI film by curing in a reducing or inert atmosphere, respectively. The Cu nanoparticles were transformed to Cu2O nanoparticles by post-heat treatment in an oxidizing atmosphere after curing in a reducing atmosphere. Transmission electron microscopy showed that uniform, round Cu2O nanoparticles 6.0 nm in diameter were dispersed in the PI film by post-heat treatment. The addition of Cu2O nanoparticles in the 4,4'-(hexafluoroisopropylidene)diphthalic anhydride-4,4'-oxydianiline (6FDA-ODA) PI film enhanced the refractive index of the 6FDA-ODA PI film from 1.60 to 1.72 at 633 nm, and the transparency of the nanocomposite film was about 70-90% in the visible region and remained around 90% beyond 550 nm.

High-Resolution Identification of Chemical States in Individual Metal Clusters in an Insulating Amorphous Polymer

“…Cu + migrates in the polyamic acid matrix via COO – ions from polyamic acid, as shown in Figure d. Recently, Choi et al suggested a similar diffusion mechanism for Cu ions by the formation of Cu 2 O nanoparticles in PI . Second, during the cooling process, the Cu atoms diffusing in PI coalesce to form Cu metal crystalline particles, and subsequent crystal growth occurs (upper left panel in Figure e).…”

“…Here, polyamic acid has two COOH moieties per monomer and COOH may lose H + to become COO − . Cu + migrates in the polyamic acid matrix via COO − ions from polyamic acid, as 18 Second, during the cooling process, the Cu atoms diffusing in PI coalesce to form Cu metal crystalline particles, and subsequent crystal growth occurs (upper left panel in Figure 6e). Cu atoms in the vicinity of the Cu substrate are then absorbed into the substrate (upper left panel in Figure 6e).…”

Optimized Magnetodielectric Coupling on High-Temperature Polymer-Based Nanocomposites

“…The variety of PI nanocomposites reported in the literqture is very wide, due to the high number of potential applications. It is possible to find examples with carbon nanotubes (CNTs), clays, and graphene and with nanoparticles, such as copper (Cu), silver (Ag), barium titanate (BaTiO 3 ),silicon dioxide (SiO 2 ),titanium oxide (TiO 2 ),or calcium carbonate (CaCO 3 ) . Nevertheless, it is difficult to find reports on the use of ferrite nanoparticles in PI for magnetism-based applications. − This type of composite is of particular interest, since ferrites are important magnetic materials with applications in the areas of sensors, electronics, communication, magnetic recording, microwave absorption-based devices, and electrical and automobile industries, as well as an increasing applicability in the biomedical and biotechnology fields. − Interestingly, ferrites can be used as a magnetostrictive phase in magnetoelectric (ME) composites, due to their high magnetostrictive coefficient (up to 200 ppm) and the high Curie temperatures (≈550 °C) among magnetic oxides. − A ME material suffers the variation of the electrical polarization as a response to an applied magnetic field or the variation of the magnetization by the application of an electric field .…”

“…7 The variety of PI nanocomposites reported in the literqture is very wide, due to the high number of potential applications. It is possible to find examples with carbon nanotubes (CNTs), 8 clays, 9 and graphene 10 and with nanoparticles, such as copper (Cu), 11 silver (Ag), 7 barium titanate (BaTiO 3 ), 12 silicon dioxide (SiO 2 ), 13 titanium oxide (TiO 2 ), 14 or calcium carbonate (CaCO 3 ). 15 Nevertheless, it is difficult to find reports on the use of ferrite nanoparticles in PI for magnetism-based applications.…”

Environmental Sensitivity of Fabry-Perot Microcavities Induced By Layered Graphene-Dielectric Hybrid Coatings

“…This can be achieved by endowing the output interface with a reflection phase shift variable with the wavelength (λ), an effect that can be produced by a thin coating which may feature an internal layered structure built at the nanoscale [18]. Different kinds of coatings have been used over the years, including dielectric multilayered structures [19][20][21], porous metal-oxide films [22] and metallic coatings based on thin metal films [23,24], plasmonic nanostructures [25] or embedded nanoparticles [26,27]. More recently, it has been reported [28] that hybrid structures made of dielectrics and very thin (but highly conducting) metallic films can show nontrivial internal interference effects that allow for an effective control over the phase shift introduced upon reflection of light.…”