Peel Adhesion Strength between Epoxy Resin and Hydrated Silica Surfaces: A Density Functional Theory Study

Abstract

Adhesive strength is known to change significantly depending on the direction of the force applied. In this study, the peel and tensile adhesive forces between the hydroxylated silica (001) surface and epoxy resin are estimated based on quantum chemical calculations. Here, density functional theory (DFT) with dispersion correction is used. In the peel process, the epoxy resin is pulled off from the terminal part, while in the tensile process, the entire epoxy resin is pulled off vertically. As a result of these calculations, the maximum adhesive force in the peel process is decreased to be about 40% of that in the tensile process. The adhesion force–displacement curve for the peeling process shows two characteristic peaks corresponding to the process where the adhesive molecule horizontally oriented to the surface shifts to a vertical orientation to the surface and the process where the vertical adhesive molecule is dissociated from the surface. Force decomposition analysis is performed to further understand the peel adhesion force; the contribution of the dispersion force is found to be slightly larger than that of the DFT force. This feature is common to the tensile process as well. Each force in the peel process is about 40% smaller than the corresponding force in the tensile process.

Shear adhesive strength between epoxy resin and copper surfaces: a density functional theory study

“…Although theoretical studies on adhesive strength have also been conducted, most of them are related to tensile adhesive strength. [7][8][9][10][11][12][13][14][15]19,21,23,24,27,28 Theoretical studies on adhesion forces for different directions have recently been conducted, 18,20,30 but further theoretical analysis of adhesion forces in various directions and its molecular understanding are required.…”

“…6 The adhesion mechanism of epoxy resins has been extensively studied both theoretically and experimentally. 7–33 At the adhesive interface, the ether group, hydroxy group, and benzene ring of DGEBA play important roles, and their interaction with the adherend surface generates adhesive strength. The structure of the adherend surface also has a significant influence on the interaction.…”

Molecular Understanding of Adhesion of Epoxy Resin to Graphene and Graphene Oxide Surfaces in Terms of Orbital Interactions

“…1−5 CFRP composites are composed of high-strength carbon fiber and a polymer matrix. 6 Usually, epoxy resin (ER), regarded as a highly functional polymer, 7,8 is used as a matrix for CFRP because of its good mechanical properties. 9−11 The mostly used carbon fibers in CFRP composites are polyacrylonitrile (PAN)-based because of their high carbon yield.…”

“…Carbon fiber-reinforced polymer (CFRP) composites are widely used in various applications such as aerospace, automobile, military, sports sector, and civil engineering structures due to the diverse physical and mechanical properties such as lightweight, high strength, and chemical stability. − CFRP composites are composed of high-strength carbon fiber and a polymer matrix . Usually, epoxy resin (ER), regarded as a highly functional polymer, , is used as a matrix for CFRP because of its good mechanical properties. − The mostly used carbon fibers in CFRP composites are polyacrylonitrile (PAN)-based because of their high carbon yield . The incorporation of nanomaterials, such as graphene, carbon nanotubes (CNTs), etc., into the ER is also promising. , In the practical application of CFRP composites, the adhesive interaction between these carbon materials and ER must be enhanced to realize the optimum potential of CFRP composites. , …”

Effects of Moisture Diffusion on a System-in-Package Module by Moisture–Thermal–Mechanical-Coupled Finite Element Modeling

“…In the literature, various methodologies were reported to characterize the effects of moisture absorption on the mechanical performance of bulk EMC and EMC/substrate interfaces, such as piezoresistive stress sensor chips for strain measurements [ 4 ], and micro-digital image speckle correlation (μ-DiSC) for interfacial fracture toughness [ 5 ]. Finite element modeling and molecular dynamics were also frequently used to study the influences of moisture absorption on the device reliability [ 6 , 7 , 8 , 9 , 10 , 11 ]. It was found that the interactions between water molecules and the chain structure of epoxy polymer during moisture diffusion can alter the mechanical and thermal performance of EMCs [ 7 , 12 , 13 ].…”