Spontaneous Patterning via Frontal Polymerization

Traditional composite manufacturing is a multi-step process limited to fabrication of uniform parts with a high time and energy cost. Patterning of materials with spatial control of mechanical properties would enable fabrication of more complex parts with unique functionality for applications beyond what is currently possible. Reaction-diffusion processes have demonstrated potential for creating patterned materials and are herein explored within an advanced method of fabricating high-performance polymeric materials and composites – frontal polymerization. Frontal polymerization (FP) uses a self-propagating exothermic reaction wave to create thermosetting polymeric and composite parts with zero energy input after simple thermal initiation without sacrificing mechanical properties, offering an alternative to traditional autoclave curing. Currently, FP is only used to create parts with uniform properties throughout, limiting the applicability of fabricated parts. The work reported herein develops tools for modulating reaction-diffusion patterning for spatial control of mechanical properties across parts fabricated via the frontal ring-opening metathesis polymerization (FROMP) of dicyclopentadiene (DCPD) and 1,5-cyclooctadiene (COD), enabling more advanced designs in one processing step.