Preparation of silvered polyimide films with reflective and electrically conductive surfaces using single‐stage self‐metallization techniques and factors affecting silver particles migration

Abstract

Reflective and surface conductive flexible polyimide (PI) films were prepared by the incorporation of silver(I) acetate and 1,1,1-trifluoro-2,4-pentanedione into a dimethylacetamide solution of several poly(amic acid)s which were prepared from dianhydrides and diamines. Thermal curing of the silver(I)-containing poly(amino acid)s precursor led to cycloimidization of the PI with silver(I) reduction and formation of a reflective and conductive silvered surface at about 13 wt % silver. Effects on silver particles migration and aggregation were discussed in this article. The results indicated that the PI structures with flexible chains and groups easily fabricate the silvered films, with both reflective and conductive characteristics. With the forced air condition, the evaporation rate of the solvent and water increases, which facilitates the migration of silver particles to give reflective and conductive silvered surfaces. Films were characterized by transmission electron microscopy, scanning electron microscopy, and tapping-mode atomic force microscopy. Electrical conductivity, reflectivity, and dynamic mechanical thermal analysis were performed on the metallized films.

Resistive Switching in Polymer Nanocomposites by Matrix-Controlled in Situ Nanoparticles Generation

“…However, for longer exposure times the film turns first to yellow (10 min UV), then to brown (30 min UV), and finally to dark brown (90 min UV). We note that after 60 min of UV irradiation, BEMA Ag film shows the characteristic brightness of a metallic surface, which is consistent with the enrichment of the Ag NPs at the surface of the film 22,31,32 (Figure 1c). UV− visible spectra at different irradiation times were also collected.…”

“…Silver surface enrichment of polymer NCs was already observed related to both heat treatments ,, and under light irradiation; , nevertheless, a complete explanation is still under debate. As previously mentioned, under light irradiation NPs undergo a mechanism of formation–growth–destruction and rebuilding.…”

“…This is in good agreement with the macroscopic and microscopic observation performed on the samples; in fact, the NCs formed with rubbery matrices showed a silver-mirror aspect, while BEDA Ag showed a brown transparent color. Silver surface enrichment of polymer NCs was already observed related to both heat treatments 31,32,44 and under light irradiation; 40,45 nevertheless, a complete explanation is still under debate. As previously mentioned, under light irradiation NPs undergo a mechanism of formation−growth−destruction and rebuilding.…”

Dual step irradiation process for in situ generation and patterning of silver nanoparticles in a photocured film

“…This is in good agreement with other works in which thermally generated Ag NPs showed similar surface accumulation. 13,15 In the present case we measured the temperature increase in the polymeric lm during the UV irradiation (see ESI †) by using a thermocouple placed in the polymeric lm but not under direct UV light, to avoid heat transfer through irradiation. A temperature increase of 16 C was measured in one hour.…”

Blue Laser Projection Printing of Conductive Complex 2D and 3D Metallic Structures from Photosensitive Precursors

“…After sintering, plenty of Ag NPs appeared on the surface of the conductive object, while only a few were in the bulk (Figure D). This difference was due to the migration of near-surface silver particles to the surface and their coalescence during the sintering process. , The large silver aggregates formed on the surface led to the metal silver appearance and introduced conductivity. However, the printed 3D object showed high bulk resistivity (1.15 ± 0.62 × 10 5 Ω cm) due to the insulating polymeric matrix and dispersed Ag NPs in it .…”