Polydopamine and Polydopamine-Silane Hybrid Surface Treatments in Structural Adhesive Applications
| Autor: | Joshua A. Orlicki, Joseph L. Lenhart, Ngon T. Tran, Daniel B. Knorr, David Flanagan, Kenneth Proctor |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Diglycidyl ether
Materials science Indoles Polymers Surface Properties 02 engineering and technology 010402 general chemistry 01 natural sciences chemistry.chemical_compound Phenols Electrochemistry General Materials Science Benzhydryl Compounds Spectroscopy chemistry.chemical_classification Aqueous solution Silanes Propylamines Bond strength Photoelectron Spectroscopy Surfaces and Interfaces Epoxy Polymer 021001 nanoscience & nanotechnology Condensed Matter Physics Silane 0104 chemical sciences chemistry Chemical engineering visual_art visual_art.visual_art_medium Epoxy Compounds Adhesive 0210 nano-technology |
| Zdroj: | Langmuir : the ACS journal of surfaces and colloids. 34(4) |
| ISSN: | 1520-5827 |
| Popis: | Numerous studies have focused on the remarkable adhesive properties of polydopamine, which can bind to substrates with a wide range of surface energies, even under aqueous conditions. This behavior suggests that polydopamine may be an attractive option as a surface treatment in structural bonding applications, where good bond durability is required. Here, we assessed polydopamine as a surface treatment for bonding aluminum plates with an epoxy resin. A model epoxy adhesive consisting of diglycidyl ether of bisphenol A (DGEBA) and Jeffamine D230 polyetheramine was employed, and lap shear measurements (ASTM D1002 10) were made (i) under dry conditions to examine initial bond strength and (ii) after exposure to hot/wet (63 °C in water for 14 days) conditions to assess bond durability. Surprisingly, our results showed that polydopamine alone as a surface treatment provided no benefit beyond that obtained by exposing the substrates to an alkaline solution of tris buffer used for the deposition of polydopamine. This implies that polydopamine has a potential Achilles' heel, namely, the formation of a weak boundary layer that was identified using X-ray photoelectron spectroscopy (XPS) of the fractured surfaces. In fact, for longer deposition times (2.5 and 18 h), the tris buffer-treated surface outperformed the polydopamine surface treatments, suggesting that tris buffer plays a unique role in improving adhesive performance even in the absence of polydopamine. We further showed that the use of polydopamine-3-aminopropyltriethoxysilane (APTES) hybrid surface treatments provided significant improvements in bond durability at extended deposition times relative to both polydopamine and an untreated control. |
| Databáze: | OpenAIRE |
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