Flexible Fibrillar Surface Array Morphology as a Function of Inter-Fibril Interactions

Mesoscale polymer ribbons (MSPs) are unique high aspect ratio filaments formed by controlled evaporative self-assembly. Upon release into aqueous solution, MSPs exhibit 3D morphologies sensitive to their geometry, material properties, and environmental interactions. This structural tunability offers a novel means to construct bioinspired hierarchical assemblies. Previous work has provided insight into the physics governing single MSP configurations, but there remains a limited understanding of the effects of inter-filament and substrate interactions on fibrillar shape and behavior. To study these influences, we fabricate surface-bound MSP filament arrays and harness interfacial forces to control their morphology. We use fluorescent microscopy to monitor the evolution of these structures as a function of ambient pH, salinity, and dissolved polymer. Using computational analysis, we correlate changes in the radius of curvature and inter-ribbon separation to environmental conditions. This work elucidates the impact of interfacial interactions and assembly phenomena in multi-ribbon mesoscale structures, underpinning the MSP as an emerging platform in soft, bioinspired hierarchical assemblies.