Dynamic behaviours of epoxy resin thin films during the curing process

Hoshino, Taiki; Okamoto, Yasushi; Yamamoto, Akira; Masunaga, Hiroyasu

doi:10.1039/d2sm01500e

Cited by 4 publications

(1 citation statement)

References 47 publications

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“…Real-space observation, such as electron microscopy, − has revealed the possibility of an interlocking or anchoring effect, , as described by the mechanical theory. Depth profiling techniques such as dynamic secondary ion mass spectroscopy (DSIMS), , X-ray/neutron reflectivity measurements, − and confocal Raman scattering have enabled us to examine the interfacial layer formed by the interdiffusion of polymers, of which the thickness directly affects the adhesion strength. − However, there seems to be very limited exploration of experimental approaches to electronic theory. X-ray photoelectron spectroscopy measurements with Ar gas cluster ion beam sputtering and transmission electron microscopy with electron energy-loss spectroscopy are plausible techniques for this purpose.…”

Section: Introductionmentioning

confidence: 99%

Electronic Interaction of Epoxy Resin with Copper at the Adhered Interface

Saeki,

Kawaguchi,

Tsuji

et al. 2024

Langmuir

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A better understanding of the aggregation states of adhesive molecules in the interfacial region with an adherend is crucial for controlling the adhesion strength and is of great inherent academic interest. The adhesion mechanism has been described through four theories: adsorption, mechanical, diffusion, and electronic. While interfacial characterization techniques have been developed to validate the aforementioned theories, that related to the electronic theory has not yet been thoroughly studied. We here directly detected the electronic interaction between a commonly used thermosetting adhesive, cured epoxy of diglycidyl ether of bisphenol A (DGEBA) and 4,4′-diaminodiphenylmethane (DDM), and copper (Cu). This study used a combination of density functional theory (DFT) calculations and femtosecond transient absorption spectroscopic (TAS) measurements as this epoxy adhesive-Cu pairing is extensively used in electronic device packaging. The DFT calculations predicted that π electrons in a DDM molecule adsorbed onto the Cu surface flowed out onto the Cu surface, resulting in a positive charge on the DDM. TAS measurements for the Cu/epoxy multilayer film, a model sample containing many metal/adhesive interfaces, revealed that the electronic states of excited DDM moieties at the Cu interface were different from those in the bulk region. These results were in good accordance with the prediction by DFT calculations. Thus, it can be concluded that TAS is applicable to characterize the electronic interaction of adhesives with metal adherends in a nondestructive manner.

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