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Molecular Investigation of the Self-Assembly Mechanism Underlying Polydopamine Coatings: The Synergistic Effect of Typical Building Blocks Acting on Interfacial Adhesion.
- Source :
-
ACS applied materials & interfaces [ACS Appl Mater Interfaces] 2024 Sep 10. Date of Electronic Publication: 2024 Sep 10. - Publication Year :
- 2024
- Publisher :
- Ahead of Print
-
Abstract
- Polydopamine (PDA) is well known as a mussel-inspired adhesive material composed of oligomeric heteropolymers. However, the conventional eumelanin-like structural assumption of PDA seems deficient in explaining its interfacial adhesion. To determine the decisive mechanism of PDA coating formation, experiments and simulations were performed in this study. 5,6-Dihydroxyindole (DHI), the signature building block of eumelanin, was introduced as the control group. Various typical building blocks in PDA were quantified by physicochemical characterizations, and the polar-group-dominated interfacial interaction was evaluated by classic molecular dynamics and metadynamics methods. Aminoethyl has been proven to be the key functional group inducing the adsorption of PDA on the hydroxylated silica substrates, while DHI shows limited adhesion to the substrate due to the absence of aminoethyl as the catechol-indole structure of DHI exhibits poor affinity to the silica surface. Pyrrole carboxylic acid, as an oxidative product detected from PDA/DHI, is unfavorable for its adhesion to silica substrates. Overall, the coating formation and self-aggregating precipitation of PDA are two competitive aminoethyl-consuming paths; thus, the in situ oxidative coupling of dopamine is indispensable for the PDA coating preparation. The collected PDA precipitates can no longer present satisfactory coating forming behavior, resulting from a shortage of aminoethyl moieties.
Details
- Language :
- English
- ISSN :
- 1944-8252
- Database :
- MEDLINE
- Journal :
- ACS applied materials & interfaces
- Publication Type :
- Academic Journal
- Accession number :
- 39256056
- Full Text :
- https://doi.org/10.1021/acsami.4c10816