Trichome entanglement enhances damage tolerance in microstructured biocomposites

TL;DR

This study demonstrates that entangling Spirulina trichomes within biocomposites significantly improves their mechanical strength and damage tolerance, offering a scalable, structure-based approach to enhance composite durability.

Contribution

It introduces a novel damage tolerance mechanism based on physical filament entanglement of microstructured biocomposites, moving beyond traditional chemical or filler strategies.

Findings

Threefold increase in yield stress with entangled trichomes

290% improvement in bending strength in 3D printed composites

Transition from interfacial debonding to crack propagation through entangled network

Abstract

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.