Dr Jean-Pierre Malval "Molecular Engineering Strategies for the Development of Highly Efficient Two-Photon Activable Initiators"

Since a decade, the field of multiphoton fabrication has developed rapidly so that it is no longer a rapid prototyping technology but a real manufacturing technique that is commercially available. Moreover, its impact is clearly growing in diverse applied domains such as nanotechnology, optics, photonic crystals, biochips, nano/micro-electromechanical systems (N/MEMS). Indeed, multiphoton fabrication constitutes a mature technology which can make possible the fabrication of intricate 3D structures with feature sizes as small as 100 nm. By tightly focusing a pulsed laser beam (ns to fs pulses) into a multi-photon absorbing material, it is possible to trigger a photoreaction (e.g. photopolymerization) inside a volume below the dimension of the voxel. Complex structures can then be generated by moving in the laser focus in the 3 dimensions inside the monomer substrate. Due to the nonlinear intensity dependence of the photoinitiating process, the spatial confinement of the reaction is guarantee and is intrinsically dependent on two parameters: i) the nonlinear absorption ability of the material, ii) the reactivity of the excited species. In this context, important research efforts have been devoted to design new photoinitiators that both exhibit efficient two-photon absorption ability (i.e. high two-photon absorption cross-section) and high initiating reactivity.

In the present lecture, we will present various several building strategies for the development of such advanced materials.

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