Novel epoxy adhesives based on conductive micron‐sized silver flowers
Yanhong Ji, Peng Miao, Ruonan Zhang, Quan Li, Yifan Zha, Fengying Dai, Xi Du, Benqiao He, Shao‐Yun Fu
Abstract
Abstract Low silver contents are desirable for electrically conductive adhesives (ECAs) due to the high cost of silver. In the present work, micro‐sized flower‐like silver particles (MFSPs) with long and thin petals are prepared by a novel, green, and facile chemical reduction method in an aqueous solution. The effects of reactant mass ratio and reactant concentration are investigated to control the morphology and size of MFSPs. Three kinds of MFSPs with different sizes are filled into an epoxy resin to prepare novel ECA. Due to the easily formed conductive paths by such morphological silver particles, the as‐prepared MFSP/epoxy composite adhesive has a low percolation threshold, a high conductivity, and high adhesion strength at a very low silver content. When considering the optimal combination of low electrical resistance and high adhesion strength, the MFSP obtained at the 1.5:1 ratio of ascorbic acid to silver nitrate is promising for preparing the ECA with a low Ag content of 30 wt% which is the lowest content for ECAs compared with the literature. The synthesis process of MFSPs has the advantages of mild condition, simple process, and environmental friendship. This study provides a new way to prepare highly conductive Ag/epoxy adhesives with low silver contents.