Dr. Arnaud Spangenberg "3D/4D Additive MicroFabrication"

Whereas different strategies have been successfully implemented for mass production of 2D/2.5D micro and nanostructures, fabrication of 3D micro and nanostructures is usually not trivial and required time-consuming multi-steps processes. In that context, additive manufacturing technology is particularly attractive but suffers from a lack of spatial resolution. Thereby, two-photon stereolithography (TPS) appears of high interest since it makes possible in a unique step the fabrication of intricate 3D structures with features sizes as small as 100 nm.[1]

However, contrary to standard additive manufacturing, TPS has not reached a sufficient level of maturity to allow value-added commercial applications. For instance, until recently, due to the serial nature of the writing process, typical writing speed was ranged from few μm.s-1 to mm.s-1, thus preventing its widespread dissemination in academic community or industrial environment.

In the frame of this seminar, I will first introduce some principles related to TPS, then I will discuss about recent achievements made by us and others both from instrumentation and material point of view. For instance, bio-inspired designs of multi-scale and complex 3D structures have been proposed and realized resulting to biomimetic materials with enhanced adhesion[2,3] or mechanical reliability[4]. Finally, a last part will be dedicated to 4D printing which will be strongly correlated to the design of advanced functional materials (adaptative materials) compatible with TPS process.[5,6]

[1] Kawata et al. Nature, 2001, 412, 697.
[2] Artz et al. PNAS, 2003, 100, 10603.
[3] Röhrig et al. Small, 2012, 8, 3009.
[4] Jang et al. Nature Materials, 2013, 12, 893.
[5] Chia Gomez et al. Advanced Materials, 2016, 28, 5931.
[6] Yu et al. Advanced Materials, 2018, 1805093, DOI: 10.1002/adma.201805093, just accepted.

invited by Prof. Günter Reiter