Peter Olmsted "Polymer Physics in Additive Manufacturing

Jeudi 7 Juin 2018 - 14h00 - Amphi Urbain

Polymer Physics In Additive Manufacturing

Peter Olmsted Department of Physics, Georgetown University

Numerous methods of Additive Manufacturing make use of polymeric materials ; examples include fused filament fabrication (FFF), selective laser sintering/melting, and bioprinting of hydrogels. These processes and their materials present many opportunities for obtaining a deeper understanding and insight into process and material design through the polymer physics of the processes. I will focus primarily on some of the challenges of FFF, and address whether and how we can understand why parts printed with this common process are often mechanically very weak, and what can potentially be done to enhance these processes. In FFF flows, relaxation, and solidification of entangled polymers under rapid cooling and heating conditions intertwine to yield the final printed parts. I will also touch on some interesting physics issues that arise in other polymer-based AM fabrication methods.

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Vendredi 8 juin 2018 - 14 h 00 - Amphi Urbain

Merging Human and Machine with Soft-Matter Technology

Xuanhe Zhao Soft Active Materials Laboratory, Massachusetts Institute of Technology

While human tissues are mostly soft, wet and bioactive ; machines are commonly hard, dry and biologically inert. Bridging human-machine interfaces is of imminent importance in addressing grand societal challenges in healthcare, security, sustainability and joy of living. However, interfacing human and machines is extremely challenging due to their fundamentally contradictory properties. At MIT SAMs Lab, we exploit soft-matter technology to bridge human-machine interfaces. On one side, soft matters such as bioactive hydrogels with similar mechanical and physiological properties as tissues can naturally integrate with human body, playing functions such as scaffolds, catheters, stents and implants. On the other side, the soft matters embedded with electronic and mechanical components can control and respond to external machines. In this talk, I will first discuss the mechanics to design extreme properties for soft matters, including tough, resilient, adhesive, strong and antifatigue, which are necessary for reliable robust human-machine interfaces. Then I will discuss a new multi-material 3D printing platform to fabricate personalized and customized microstructures devices of soft matters. Based on the soft-matter design and fabrication technologies, we create a set of soft-matter devices such as i). long-term high-efficacy hydrogel neural probe, ii). ingestible and GI-resident hydrogel machine, and iii). untethered fast and forceful hydrogel robots controlled by magnetic fields. I will conclude the talk by proposing a systematic approach to design next-generation human-machine interfaces based on soft-matter technology.