ABSTRACT

This investigation was focused on the influence of polymer hydrophilicity on the morphological structure and mechanical properties of copper-in-polymer gradient composite films (CPGCFs). The ion motion and reduction in swelling cathode films under an electric field were the core of the gradient morphology formation of a metal region in the polymer matrix. The morphological study of CPGCFs revealed that the hydrophilicity of poly(vinyl alcohol) was helpful in forming a continuously deposited layer. The nanoclusters (40 nm) aligned into a branchlike form in the copper-rich region in the poly(vinyl alcohol) matrix. On the basis of the fuzzy interface between the poly(vinyl alcohol) matrix and copper nanoclusters, a complex interaction between them was inferred. The reduced copper affected the mechanical properties of CPGCFs. The maximum load of CPGCFs could be enhanced by 25% to 167.0 N with optimal electrochemical reduction, but the elongation was depressed. An excess of reduced copper in the polymer matrix reduced both the strength and elongation of CPGCFs. The moduli of related samples showed trends similar to those of the strength. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 539–545, 2005

In this paper, the influences of composition of copolymers and acidity of electrolyte in an electrochemical reactor on morphological structure of copper-in-polymer gradient composite film were investigated. For binary copolymers, poly(acrylonitrile-co-methyl acrylate) [P(AN-co-MA)] and poly(acrylonitrile-co-sodium allyl sulfonate) [P(AN-co-SAS)], the charged group SO in P(AN-co-SAS) improves the swelling of the copolymer phase and copper reduction to form gradient morphology; the carboxylic ester group in P(AN-co-MA) is not effective because of its poor hydrophilicity, but it is a cooperating component with P(AN-co-SAS) to avoid excess of counterion (i.e., Na⁺) in SCF, which might severely interrupt Cu²⁺ coexistence. The swelling of the polymer phase is helpful to decrease the energy of the transfer ions in SCF and to enhance copper deposition and gradient formation. The increase of surface energy because of cluster growth raises the surface energy level of deposited Cu⁰ clusters. The conteraction between these two energy factors allows the size of clusters to be 50–100 nm. The appropriate H⁺ concentration improves active Cu²⁺ reduction and thus deposited gradient copper phase in the copolymer matrix. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 373–380, 2004

The effects of processing methods—free casting and spinning—on dispersion of nano-ZnO in a polyacrylonitrile (PAN) matrix were studied for this article. From observation with an transmission electron microscope, it was found that monoaxial drawing in spinning processing formed a fiberlike image of the nano-ZnO phase in the PAN matrix. The geometric parameters—the diameter and ratio of the nanoparticle phase—were about 20 and 15 nm, respectively, when the concentration of nano-ZnO was 1 wt % in the PAN matrix, whereas spherelike morphology was obtained by free casting, for which, naturally, the ratio of its length to its diameter was unity. This indicates that evidently the morphology of the nanoparticle phase is affected by processing methods. However, when the concentration of nano-ZnO went up to 2 wt % in the PAN matrix spinning process, the linear ratio of length to diameter of the nanoparticle phase decreased to 2.9 because drawing energy adsorption, through deformation of the nanoparticle phase, became a marked effect. The degree of anisotropy, including crystallization and orientation of polymer, was also affected by the concentration of nano-ZnO for the same reason. When the concentration of nano-ZnO reached 2 wt %, the anisotropy of PAN was obviously depressed according to the results of wide-angle X-ray measurement. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1053–1057, 2003