Multimaterial Morphogenic Growth Printing

Biological systems achieve exceptional mechanical integration by seamlessly combining materials with vastly different properties. Replicating such architectures remains a central challenge in additive manufacturing (AM), where most multimaterial techniques generate discrete interfaces between dissimilar polymers. My talk will introduce multimaterial morphogenic growth printing (MMGP), a bio-inspired fabrication method that harnesses frontal ring-opening metathesis polymerization (FROMP) to enable spatially controlled material growth. This advance builds upon morphogenic growth printing¹ via the integration of multiple reactive resins within a single, self-propagating print. Specifically, we formulate a suite of co-monomeric and graft-copolymer inks composed of cyclooctadiene (COD) and norbornene-functionalized polydimethylsiloxane (nor-PDMS). Upon curing, the patterned materials span more than six orders of magnitude in stiffness, from soft elastomers (E ≈ 1 MPa) to rigid thermosets (E ≈ 2 GPa). DCPD acts as a reactive dopant, sustaining front propagation in otherwise low-energy-density resins and enabling MMGP of graft-copolymer materials previously inaccessible to frontal curing methods. By tuning resin composition and front energetics, MMGP enables morphogenesis-inspired engineering of interfaces—ranging from continuous mechanical gradients that mimic tendon-to-bone transitions to discrete, separable boundaries reminiscent of articulating joints. These interfaces exhibit exceptional cohesion without delamination, even under repeated flexural loading. To demonstrate these capabilities, we printed flexural (finger-like) and ball-and-socket (shoulder-like) motifs via the sequential immersion of growing prints into soft, stiff, and graft resin baths.  

References

[1]       Kim, Y. S.; Zhu, M.; Hossain, M. T.; Sanders, D.; Shah, R.; Gao, Y.; Moore, J. S.; Sottos, N. R.; Ewoldt, R. H.; Geubelle, P. H.; Tawfick, S. H. Morphogenic Growth 3D Printing. Advanced Materials 2025, 37 (20).