Surface Functionalization of Micrometer Silver Flakes for Fabricating High-Performance Electrically Conductive Adhesives

Abstract

Silver (Ag) flakes are widely used as conductive fillers in the electrically conductive adhesives (ECAs). However, there are organic lubricants on the Ag surface such as oleic acid and stearic acid, a kind of surfactant commonly used in the production of Ag flakes, which will deteriorate the conductivity and mechanical properties of the ECAs. In this study, glutaric acid was used to remove the organic lubricants, which can increase the electrical conductivity and mechanical properties of the ECAs. FTIR, Raman, and XPS tests revealed that the glutaric acid was chemically adsorbed on the Ag surface by single-dentate coordination and then reacted with organic lubricants, explaining the action mechanism by which the glutaric acid enhanced the electrical and mechanical properties of the ECAs. In addition, the effects of glutaric acid on the thermal stability, bulk resistivity, shear strength, and viscosity of the ECAs were investigated. When the glutaric acid reached 0.12 wt %, the minimum bulk resistivity of the ECAs was 1.52 × 10–4 Ω·cm, the shear strength was 24.57 MPa, and the viscosity was 149 Pa·s. This provides a method for fabricating high-performance ECAs.

Superstable, High-Conductivity Cu Conductive Adhesive

“…When the temperature increased to 250 °C, the resistivity decreased significantly and reached a minimum of 65.12 μΩ·cm –1 at 30 min. This result is much better than previously published papers, ,,,− ,,,− , and the details are shown in Table . Nevertheless, abnormal phenomena materialized at 300 °C.…”

“…Owing to the high-temperature environment, the diffusion of oxygen atoms and reactivity enhanced, resulting in the oxidation of internal Cu-FA/DT, which leads to the deterioration of the conductivity of the device. Overall, the device still maintains a low resistivity, even lower than the original resistivity in the literature. ,,,− ,,,− , …”

“…Overall, the device still maintains a low resistivity, even lower than the original resistivity in the literature. 4,5,7,[11][12][13]16,22,[29][30][31]36 ■ CONCLUSIONS In this article, we demonstrate an effective method for preparing Cu ECAs with high stability and high conductivity under environmental conditions. The modification of a formic acid anion and organic mercaptan made Cu ECAs possess excellent oxidation resistance and higher electrical conductivity.…”

“…The polymer matrix, e.g., epoxy, − polyurethane, or poly­(dimethylsiloxane) (PDMS), usually governs their thermal and mechanical properties. The conductive fillers, e.g., metallic microflakes, − nanoparticles, − and nanowires, − mainly determine their electrical conductive performance. Gold and silver are limited by their expensive price, while carbon or MXene materials possess low filling density owing to their large specific surface area and poor dispersion. − In addition, liquid metals are also used for conductive adhesives, but their phase transition at high temperatures can cause reliability issues .…”

Size Optimization of Spherical Silver Nanoparticles Synthesized with Baicalin and Sodium Dodecyl Sulfate Using Response Surface Methodology

“…Nanoscience is the study of very small things and is essentially interdisciplinary, for example in the fields of chemistry, biology and materials. Nanomaterials are materials with dimensions of 1 nm-100 nm, and silver powders are available in shapes such as flakes [1], spheres [2], rings [3], triangles [4], and lines [5]. As a nano-powder material due to its unique electrical, optical, catalytic, thermodynamic, and antibacterial properties, nano-silver powder has been widely used in the direction of conductive pastes [6], solar cells [7], antibacterial materials [8], catalytic industry [9], and food encapsulation [10].…”