Estimation of the Interfacial Adhesion Strength in Compositional Libraries of Epoxy Films
Jae Hyun Kim, Martin Y. Chiang, D Kawaguchi, Gareth Royston, Christopher M. Stafford
At the NIST Combinatorial Methods Center (NCMC), we have designed, developed, and demonstrated a combinatorial approach to the edge delamination test to char-acterize the adhesion of thin polymer films. This test is based on fracture of a film/substrate interface possessing an initial interfacial crack at a stress-free edge. To fabricate a specimen for the combinatorial edge delamination test, the film/substrate bi-layer is diced into rectangles approximately (1 to 2) cm2 using a wafer saw or similar technique. The dicing process initiates small defects (cracks) between the film and substrate. Upon cooling the sample, crack extension (debonding) is driven by stresses generated by the CTE mismatch between the two materials at the interface. When the internal stress equals the interfacial fracture energy, the adhesion at the interface fails and the crack propagates from the edge of the sample towards the center.This metrology provides a rapid screen for interfacial adhesion of a wide variety of materials systems, particularly glassy and thermoset polymeric materials. Previous research on the combinatorial edge delamination test focused on applying gradients in thickness of the film, surface energy of the substrate, and temperature. There would be considerable value in incorporating compositional gradients into this measurement platform. Optimization of material properties of a multi-component material requires time-consuming formulation and exhaustive testing. High-throughput screening offers rapid assessment of new candidate materials and can define appropriate operating windows and tolerances, based on new material suppliers, new formulations, and/or changes in processing conditions. Therefore, we are pursuing methods for depositing compositional gradients of viscous formulations in appropriate library geometries for the combinatorial edge delamination test.
, Chiang, M.
, Kawaguchi, D.
, Royston, G.
and Stafford, C.
Estimation of the Interfacial Adhesion Strength in Compositional Libraries of Epoxy Films, 29th Adhesion Society Annual Meeting, Jacksonville, FL, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=852573
(Accessed June 8, 2023)