Materials Science Award (prev. Wasserman Award) -2023- Alvaro Charlet
Mechanical reinforcement of hydrogels through physical crosslinks and double network granular architecture
EPFL thesis n°9173
Thesis director: Prof. E. Amstad
For his innovative contribution to the 3D printing of load-bearing hydrogels. In particular, for the introduction of 3D printable double network granular hydrogels.
In this thesis, we have studied the mechanical reinforcement of hydrogels and demonstrated their potential as 3D printable materials. We have shown the use of hydrogel microparticles as micro-building blocks, to fabricate granular hydrogels. By linking these micro-building-block through a second percolating hydrogel network, we have fabricated double network granular hydrogels. We discovered that these materials exhibit an extraordinarily high strength and toughness. Furthermore, the jammed microparticle precursor ink enables the extrusion and 3D printing of this material. This allows the fabrication of hydrogels with locally varying compositions, which can be utilized for example to design stimuli responsive materials. We leveraged the granular structure to design recyclable double network granular hydrogels. This is achieved by forming a percolating network that has reversible covalent bonds. We show that this method can be extended to the fabrication of degradable hard plastics.
In summary, we demonstrated several solutions to combine mechanical reinforcement of hydrogels, and state of the art manufacturing. We believe that soft material science will greatly benefit the development of complex materials for novel biomedical and soft robotic applications.