Kavli Affiliate: Chiara Daraio
| First 5 Authors: Israel Kellersztein, Israel Kellersztein, , ,
| Summary:
Achieving damage tolerance in composite materials remains a central challenge
in materials science. Conventional strategies often rely on filler
incorporation or chemical modification, which can limit energy dissipation and
constrain structural stability. Here, we leverage the unique morphology of
Spirulina trichomes to investigate a reinforcement mechanism based on physical
filament entanglement. By comparing helical trichomes with their
morphologically straightened counterparts, we isolate filament geometry as the
key parameter governing mechanical performance. Trichome-based suspensions
exhibit enhanced viscoelastic response and a threefold increase in yield
stress. When processed via extrusion-based 3D printing using hydroxyethyl
cellulose (HEC) as a matrix, entangled trichomes yield a 290% improvement in
bending strength and a 15-fold enhancement in work of fracture. Fracture
surface analysis reveals a transition from interfacial debonding and pull-out
(in filaments) to crack propagation through the entangled network, indicating
structure-mediated toughening. These findings establish trichome entanglement
as a scalable, physically driven mechanism for enhancing damage tolerance
through microstructural architecture.
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