RESUMO
The values of the surface potentials of two sides of films of polyvinylidene fluoride, and its copolymers with tetrafluoroethylene and hexafluoropropylene, were measured by the Kelvin probe method. The microstructures of the chains in the surfaces on these sides were evaluated by ATR IR spectroscopy. It was found that the observed surface potentials differed in the studied films. Simultaneously, it was observed from the IR spectroscopy data that the microstructures of the chains on both sides of the films also differed. It is concluded that the formation of the surface potential in (self-polarized) ferroelectric polymers is controlled by the microstructure of the surface layer. The reasons for the formation of a different microstructure on both sides of the films are suggested on the basis of the general regularities of structure formation in flexible-chain crystallizing polymers.
RESUMO
Embedded copper mesh coatings with low sheet resistance and high transparency were formed using a low-cost Cu seed mesh obtained with a magnetron sputtering on a cracked template, and subsequent operations electroplating and embedding in a photocurable resin layer. The influence of the mesh size on the optoelectric characteristics and the electromagnetic shielding efficiency in a wide frequency range is considered. In optimizing the coating properties, a shielding efficiency of 49.38 dB at a frequency of 1 GHz, with integral optical transparency in the visible range of 84.3%, was obtained. Embedded Cu meshes have been shown to be highly bending stable and have excellent adhesion strength. The combination of properties and economic costs for the formation of coatings indicates their high prospects for practical use in shielding transparent objects, such as windows and computer monitors.
