@inproceedings{01JWV0XW85ZX7QA1EGNYY4FAJM,
  abstract     = {{Adhesive joining is increasingly preferred over mechanical joining in high-end applications, because of better stress distribution, lower weight, and the ability to join dissimilar materials. However, adhesives have lower mechanical strength compared to mechanical fasteners. Currently, they cannot achieve the high standards in terms of mechanical properties that are required for the high-end materials of the future. To address this, different kinds of nanomaterials have been added as reinforcements, successfully increasing the mechanical properties. Though the results vary greatly and the exact toughening mechanisms remain debated. Here, hafnium oxide nanocrystals (HfO2 NCs) are introduced into epoxy-based adhesives as a model system to elucidate the effect of the particle size and surface chemistry on these toughening mechanisms. The NCs act as both tunable nano tougheners and contrast agents, enabling dynamic visualization of the adhesive joint through high-resolution X-ray computed tomography (micro-CT). We synthesize HfO2 NCs in two size ranges (5-10nm and 15-20nm), through a microwave-assisted and a surfactant-assisted method respectively. The particle’s surface chemistry is tuned as to achieve a homogeneous dispersion in the polymer matrix. The ideal ligand is found to have a strong binding anchoring group (bisphosphonate) and an organic tail matching the polarity of the polymer (ethylene glycol oligomers). This ligand is synthesized in-house, providing total control over the surface. The adhesive joints, containing different loading of well-dispersed NCs, are tested for their mechanical properties and the joint is visualized with both micro-CT and scanning electron microscopy (SEM). Our results show the power of the HfO2 NCs as a tunable model system and gave insight into the roles of particle size and surface chemistry in nanoreinforced adhesives.}},
  author       = {{De Vos, John and Rooms, Pauline and Boone, Matthieu and Van Paepegem, Wim and De Buysser, Klaartje}},
  language     = {{eng}},
  location     = {{Strasbourg}},
  publisher    = {{European Materials Research Society}},
  title        = {{Cracking the code of nanoreinforced adhesives: the roles of particle size and surface chemistry}},
  year         = {{2025}},
}