walsh-usingmolecular-2020.pdf (7.29 MB)
Using molecular entanglement as a strategy to enhance carbon fiber-epoxy composite interfaces
journal contributionposted on 2020-08-18, 00:00 authored by Daniel Eyckens, B Demir, James Randall, T R Gengenbach, Linden Servinis, Tiffany WalshTiffany Walsh, Luke HendersonLuke Henderson
The tethering of an amphiphilic molecule to the surface of carbon fiber resulted in significant (+283%) improvements in interfacial shear strength. Molecular dynamics simulations revealed that lateral association of hydrophobic sections lead to a ‘hooked’ conformation through which polymer chains become entangled. Further simulations indicated that a small molecule, forced into this conformation via two covalent attachment points to the fiber surface (similar to a ‘horseshoe’), would provide similar adhesion improvements and confirm this conformational effect on interfacial phenomena. This prediction was confirmed by the synthesis and grafting of such a molecule to a carbon fiber surface, giving an almost identical improvement in interfacial adhesion (+276%). This work validates the use of molecular dynamics to inform molecular architectural design and demonstrates the translation of molecular conformation and shape at a composite interface from nano-to macroscale.