Chemistry, diffusion and cluster formation at metal-polymer interfaces

Abstract

This paper shows how structure and formation of metal‐polymer interfaces depend strongly on the preparation process and the interfacial chemistry. Emphasis is placed on results obtained from transmission electron microscopy (TEM), X‐ray photo electron spectroscopy (XPS), radiotracer measurements and computer simulations on the early stages of interface formation during noble‐metal deposition onto fully cured polymers. Noble metal atoms deposited onto polymers diffuse on and inside the polymer and tend to agglomerate to clusters. XPS results show that no significant diffusion occurs from larger clusters and is therefore also not expected from a continuous metal film. Thus the extent of diffusion into the polymer appears to be determined only by the initial stage of the deposition process and increases strongly at low deposition rates and elevated temperatures, where a large fraction of isolated metal atoms is able to diffuse into the polymer before being trapped by other atoms at or near the surface. Our results point to a strong interplay between chemical interaction, diffusion and agglomeration.

Composition dependence on dispersion of Au/Cu bimetallic nanoparticles in nylon 11 thin films

“…In order for the penetration of the particles into the nylon 11 film to be energetically favorable, the Gibbs free energy of a metal particle must be lower than that of the isolated particle at the nylon 11 surface. If the surface tension of the particle γ particle exceeds the sum of the interfacial tension γ particle−nylon and the surface tension of the nylon 11 γ nylon , embedding of the metal particle is energetically favorable [22,23], γ particle > γ particle−nylon + γ nylon (1) i.e., nylon 11 matrix can wet completely the surface of the particles. In the previous work, we have shown that the inequality (1) is obeyed for the Au/nylon 11 system [19].…”

Surface and mechanical analysis of metallized poly(dimethylsiloxane) gel for varifocal micromirrors

“…20 Higher energy values are reported to improve metal deposition and stability on PDMS surfaces, but no accurate values have been published. 15 Instead, for other polymers, such as poly(acrylonitrile butadiene styrene), the surface energy is increased after Ar-plasma treatment from σ s = 40 to 75 mN/m, which doubled the adhesion strength of a sputtered Cu-layer. 29 With σ s = 40 mN/m, the adhesive strength of 8 MPa is already quite high for nonactivated polymer surfaces and could be a surface energy value for sufficient PDMS metallization.…”

“…This process is enhanced by the highly mobile macromolecular chains of the PDMS gel and increased temperatures due to the deposition process. 14,15 To avoid the undesired diffusion, many different activation processes like O 2 -plasma, [16][17][18] photochemically produced ozone (UV/ozone), [19][20][21] corona discharges 22 or the plasma polymerization of tetraethyl orthosilicate 23 and hexamethyldisiloxane 24 monomers are already known. These methods increase the surface energy and functionality of the PDMS surface and form a hard organoceramic layer as interface between the polymer and the metal layers.…”

“…Especially noble metals with high cohesive energy such as gold and silver tend to diffuse deep into the pure polymer and further agglomerate into metal nanoparticles. This process is enhanced by the highly mobile macromolecular chains of the PDMS gel and increased temperatures due to the deposition process 14,15 . To avoid the undesired diffusion, many different activation processes like O 2 ‐plasma, 16–18 photochemically produced ozone (UV/ozone), 19–21 corona discharges 22 or the plasma polymerization of tetraethyl orthosilicate 23 and hexamethyldisiloxane 24 monomers are already known.…”

Two-Dimensional Dynamics of Metal Nanoparticles on the Surface of Thin Polymer Films Studied with Coherent X Rays

“…To extract residual toluene, the film is annealed at about 10 ÿ6 mbar for 12 h at 30 K above the glass transition temperature of the bulk polymer (T G ) and then cooled down to 300 K at a slow rate of about 20 K=h. The gold clusters are produced in a high vacuum chamber by thermal evaporation of gold from a molybdenum crucible onto the polymer surface with a deposition rate of about 0:5 A= min, while the polymer surface is held at room temperature, leading to the confinement of the clusters in a narrow surface region [9]. The metal-metal interaction being much stronger than the metal-polymer one, the gold atoms diffuse on the polymer surface during the evaporation until they nucleate or eventually desorb again [10].…”