Fluid-Mediated Fabrication of Soft Materials: From Elastomeric Beads to Functional Coatings

Apr 24

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Monday, April 24, 2023 – 9:00AM to 10:00AM


Bevand Keshavarz

Recent advances in soft apparatuses have underlined the crucial importance of graded soft materials in biomedical and biological interfaces, drug delivery, cosmetics, food science, soft robotics and adhesion. Dynamic functionality of these composite soft materials is a key element for emerging applications in life and environmental health. However, most of the design approaches are based on static mechanical properties, leaving the dynamic parameter space for man-made graded soft materials completely unexplored. A design strategy that connects gradients in dynamic viscoelastic properties to the overall adaptable functionality of the structure is still missing. These connections are somehow embedded in the fluid-mediated biofabrication processes of natural multifunctional fibers such as mussel byssus thread; but multiphysics complexity in such phenomena has so far hindered their translation to man-made structures.
In this talk I will outline my bio-inspired approach to achieve a rheo/geo-metrical design that is based on fluid-mediated fabrication of soft materials. My interdisciplinary research addresses three key aspects of this approach: (i) the intricate fluid dynamics of coating and pattern formation in viscoelastic liquids, (ii) the hierarchical organization of dynamic properties during gelation, and ultimately (iii) the mechanical spectroscopy of the fabricated structure. I will first show how the dynamics of viscoelastic fluids in complex flows affects the morphology of formed patterns and fragments, especially in spray-coating and particle synthesis applications. Going beyond polymeric liquids, I will discuss how a bio-inspired molecule DOPA (dihydroxy-phenylalanine) and its metal-ligand coordination complexes enable us to reversibly control the dynamic functionality of these structured fluids and use them as curable hydrogel coatings. Using this novel shape-memory mechanism, we can control the geometrical shape of a coated substrate such as human hair via changes in pH. Lastly, I will discuss how a similar bio-inspired approach of hierarchical organization of dynamic properties can be extended and applied to other important challenges in human life.