ORGS1-0421
Effect of Adherent Surface Chemistry on Interfacial Conformation and Adhesion Property of Epoxy Resins
Topic
GS1. Graduate Student Oral Session I: Colloidal and Interfacial Polymer Science
When and Where
Sep 28, 2026
15:36 - 15:48
Room 101
Session Chairs
Yoon-Ho HWANG
Jang-Hwan KIM
Hyosung AN
Presenter(s)
Koyu Eto (Kyushu University)
Co-Author(s)
Abstract
The aggregation states of polymer chains at buried solid interfaces play crucial roles in the adhesion properties. Thus, it is necessary to gain a deeper understanding of the molecular structure at adhesion interfaces. For example, the surface chemistry of the adherent is one of the key factors to control the aggregation states at the adhesion interfaces, thereby affecting adhesion properties. In this study, the effect of adherent surface chemistry on the local conformation of cured epoxy resin (ER) and its relationship with adhesion properties was investigated by applying sum-frequency generation (SFG) vibrational spectroscopy and molecular dynamics (MD) simulations in conjunction with surface and interfacial cutting analysis system measurements. Quartz substrates with different surface chemistries were prepared by piranha treatment and subsequent thermal annealing. SFG spectroscopy revealed that thermal annealing reduced the surface density of silanol groups of quartz substrates, and water contact angle measurements further showed that this change altered the surface wettability. Bisphenol A diglycidyl ether and 4,4′-diaminodiphenylmethane were mixed at a stoichiometric ratio, and the mixture was cured on these substrates. SFG spectra in the OH stretching region for the ER/quartz interfaces indicated that more hydrogen-bonded OH groups were present at the ER/piranha-treated quartz interface. This result was also supported by MD simulations, which further revealed that hydrogen bonding between ER and the quartz surface was significantly enhanced at the piranha-treated quartz interface. Furthermore, the peeling strength was larger for the ER/piranha-treated quartz interface than for the ER/thermally-annealed quartz interface. These results indicate that the surface chemistry of the adherends, particularly the surface density of silanol groups, enhances interfacial hydrogen bonding between ER and the adherends, resulting in increased adhesion strength.
