Nowadays, there is a growing demand for compact and elaborate 3D microsystems to fullfill the requirements in various fields such as nanomechanic, nanophotonic, nanofluidic, nanomedecine or biology. 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 this context, additive manufacturing technology (AMT) 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. Besides, recent achievements regarding the writing speed have underlined the potential of TPS as a sub-micro scale additive manufacturing and confirmed its emerging role as a key enabling technology in a near futur. Nevertheless, contrary to standard AMT, TPS has not reached a sufficient level of maturity to allow value-added commercial applications, and even more surprising, its use is still limited to some academic communities. Nowadays, in order to traverse the threshold of industrialization and favor TPS dissemination in all academic communities, one remaining challenge consists to develop and characterize functional materials compatible with the TPS process. Whereas we and other have very recently proposed innovative functional materials compatible with TPS, the impact of this fabrication process on the final properties have been scarcely investigated due to the complexity of the process. Indeed, contrary to most standard conventional photopolymerization applications such as UV curing and coating, TPS presents specific reaction conditions such as highly localized (< µm3), intense and short laser pulse excitation which limit its full investigation by conventional methods (FTIR, Raman, PhotoDSC,…). Besides, owing to the little amount of polymerized material, standard analysis such as HPLC are not possible. Finally, at these time and space scales, many phenomenons have to be taken in consideration such as molecular diffusion, optical aberration, local heating, post-polymerization and so on… Therefore so far, TPP’s studies have been mostly limited to the analysis of geometrical shape and size of the smallest features (called voxel) or of suspended lines in function of the writing fabrication parameters (exposure time and power). In this context, 2PhotonInsight aims to unraveling the two photon polymerization (TPP) reaction occurring during the 3D direct laser writing process. In that purpose, a first task will consist to characterize the final properties of the material from a geometrical, chemical and mechanical point of view. To achieve this goal, conventionnal (SEM, Raman microspectroscopy) and novel approaches (laser vibrometry) will be performed. In a second task, the kinetic of the TPP photoreaction will be investigated. In that regard, one needs to propose method with time (ten to hundred of µs) and spatial (sub-µm) resolution compatible with the TPP reaction, therefore novel strategies based on fluorescent molecular probes sensitive to the viscosity will be attemped. These two first steps will lead to a better understanding of the TPP reaction which is crucial to exert a better control on the processing route and achieve to build relationships between final properties of the materials and the conditions of fabrication. Finally, in order to illustrate the interest of our approach, we will take advantage of the resulting knowledge to design well-characterized surface model for cell biology and to assess the impact of each fabrication parameter on the cell behavior.

Polymers are truly shaping today’s world and can be found everywhere, from commodity plastics to high-end technologies. As chemists, this raises an important question: Can we make plastics more sustainable by using resources that can act as an alternative to the current fossil-based solutions, and thus to design a circular economy process from the ground up? Therefore, the aim of the current proposal is to deliver value by diverting waste (e.g., an elemental sulfur, S8, a surplus by-product of natural-gas and petroleum refining operations) from landfills, moving materials up the waste hierarchy and producing quality polymers and materials. Importantly, the polymers and materials thereof are competitively priced and have a smaller environmental footprint than those made with petroleum-based ones. To this end, an underrated multicomponent redox polycondensation of readily available starting materials and S8 will be employed at the interface of organic synthesis and polymer chemistry for furnishing cost-effective novel class of polymers (i.e., poly(thiomalonamide)s) that could not be accessed by any other synthetic methods. The proposed strategy will also enable new opportunities to construct functional materials with application-oriented properties.

Stimuli-responsive materials have emerged but their industrial applications remain limited. The whole composition of the system is usually specifically formulated to react to environmental conditions although many phenomena locally occur at the surface of the material. This strategy is thus economically non-viable because only few percents of the material volume are exploited for their smart properties. Consequently, industrial renewal can be stimulated by the fabrication of stimuli-responsive coatings that will cover the material, preserving the characteristics of the bulk material and limiting the cost of these additional smart properties while modifying its sensitivity to the surrounding environment. Two challenges appear: i) the development of efficient interfacial dynamic systems, controlled by an external stimulus, and ii) the incorporation of these systems in a ‘universal’ surface modification process. In that context, the INTHERMO project aims at designing smart interfaces with switchable properties, in particular thermo-reversible properties, via a substrate-independent process. These surfaces will react through thermally-reversible Diels-Alder (DA) chemistry. This chemistry is a good candidate to reach such properties since it exhibits dynamic covalent bonding under certain conditions and has also been classified among click chemistry reactions, being efficient and selective. In addition, the elaboration of such surfaces will be assisted by plasma polymerization which enables the fabrication of functional polymer films on a wide variety of substrates (various natures of substrates, including thermo-sensitive materials, various shapes), thus using a universal surface modification process. Grafting of interfacial DA compounds on these reactive coatings will bring the required properties to the polymer film and enable the production of smart interfaces with thermo-reversible properties. The INTHERMO project develops the concept of thermo-reversible covalent bonding on surfaces by i) thoroughly investigating interfacial DA chemistry to elucidate the dependence of the plasma polymer properties on the surface reactivity and ii) developing new DA couples for interfacial thermo-reversible chemistry, reacting under mild conditions (relatively low temperatures for direct and reverse DA reactions, reactions in water). The results of these works will lead to the fabrication of samples illustrating the concept of original interfacial DA chemistry for two precise industrial applications. First, this concept can be applied to reversible covalent adhesion of materials to consider easy replacement of damaged pieces (for instance in composite materials or microelectronics). Covalent assembly of materials at low temperature (via direct DA reaction) and disassembly of elements at a higher temperature, that doesn’t degrade many common materials (via reverse DA reaction), is a great challenge for recyclability of complex system assemblies. Secondly, thermo-reversible DA reaction confined in thin, functional polymer coatings can be used for thermally-controlled immobilization and release of (bio)molecules at/from a substrate. This strategy can find interest for the separation of (bio)molecules from a complex medium while addressing an efficient regeneration of the substrate after use. This 36-month research project, coordinated by a Young Researcher working at the Institute of Materials Science of Mulhouse (IS2M), will target a unique combination of original interfacial DA chemistry, operating under mild conditions, with a substrate-independent process based on plasma polymerization, so that smart interfaces become a reality for specific industrial applications.

MATIAIRE industrial research project is in the scope of European concerns and difficulties in the field of agriculture production which faces many challenges: serve European food sovereignty a medium-term geopolitical issue, as much as an environmental one. Food systems must become sustainable in order to be resilient and able to go through current crisis than can be sanitary (or environmental (ie.climate change, droughts and floods). Secondly, and concomitantly with the first challenge the means of production at the national and European level must be questioned and optimized, in particular the fertilizing inputs and the reduction of antibiotics uses. Finally, in addition to these political, social and economic issues, there are additional uncertainties related to the consequences of climate change. MATIAIRE project involving Timac Agro, a french leading company specialized in soil nutrition, plant nutrition and animal production, having 7210 employees all over the world, and the Institute of Material Science of Mulhouse (IS2M) aims at developing and bring to the market, a new generation of biostimulants to secure agricultural production in the face of climatic hazards, increase the efficiency of use of fertilizer inputs, enhance animals robustness and immunity and control greenhouse gases emissions from animal production. In order to fulfil these objectives, an innovative pluri and interdisciplinary approach is proposed with an ambitious scientific program involving the tailor-made design of new materials for uses in the field of plant and animal nutrition, by an environmental-friendly process from lab to industrial scale. Beside the scientific and technical challenges to face, the chair’s program aims also at providing training for students and professionals and dissemination of the knowledge toward general public.

Controlled radical polymerizations have remained underexploited so far at the industrial scale with regard to their exceptional synthetic potential. Any proposition aiming at exploiting them for new high-added-value applications, overcoming by the way their restricting extra cost compared to free radical polymerizations, would thus constitute an outstanding breakthrough in the field, likely to renew their interest from an industrial point of view. The RAFT-POP project comes within this framework by aiming at valorizing the reversible addition-fragmentation chain transfer (RAFT) mechanism as a versatile synthetic platform for the design of well-defined polymers as new macrophotoinitiators exhibiting an enhanced photodissociation efficiency and more generally as precursors for new light-induced macromolecular engineering reactions. This concept relies on the sensitivity to light of RAFT end-groups, resulting directly from the structure of the chain transfer agents used: these thiocarbonylthio compounds, such as dithiocarbamates or xanthates, were already commonly used as photoinitiators or photoiniferters before the discovery of RAFT. This reactivity will be here highly boosted by the introduction of a chromophore at the vicinity of the C-S photodissociable bound. The application of the RAFT process at the industrial scale has been hindered up to now in particular by the undesirable presence in the final products of these thiocarbonylthio end-groups, which can cause for instance their coloration and remain generally sensitive to light or heat. In the RAFT-POP project, these end-groups are no longer considered as a drawback but become, on the contrary, key-functions for new possible applications of RAFT polymers. Concretely, the chromophore is introduced straightforwardly via the RAFT polymerization mechanism, either as a side group on the terminal monomer unit, or as the Z group of the chain transfer agent. These two strategies will result in two classes of photoactive macromolecular precursors, which will be synthesized and investigated in the project. Both of them will be first of all investigated as precursors for new macromolecular syntheses methodologies that will combine RAFT with original photo-induced reactions, as well as with other controlled polymerization mechanisms. In particular, photo-induced radical couplings or chain-end modifications, enabling the switching to another mechanism, will be considered. In a second main field of investigation, these RAFT polymers will be implemented as macrophotoinitiators, strictly speaking. After preliminary kinetic studies, they will be used first of all for the preparation of photopolymer coatings based on multifunctional acrylates. Interestingly, some structures will be also original macrophotoinitiators for radical promoted cationic polymerization and will thus be implemented for the preparation of epoxy coatings. The polymer nature of these macrophotoinitiators can bring several advantages over photoinitiators classically used. First of all, a lower extractability of the unreacted fraction is expected. Then, they can play the simultaneous role of additives, enabling the tuning of the final properties of the photopolymer through the length, composition and density of the chains synthesized by RAFT. Finally, it is also a means to increase the initial miscibility of a photoinitiator in a formulation. Some precursors will be optimized macrophotoiniferters which should allow the fabrication of multilayer coatings implying covalently bound interfaces. The development of an optimized “photoRAFT” mechanism should also derive from this reactivity. Finally, macrophotoinitiators with graftable or polymerizable side groups will be investigated as a means to reinforce interfaces between a photopolymer coating and its substrate or as a supplementary means to reduce extractability issues, respectively.