Sunlight Induced Polymerization Photoinitiated by Novel Push–Pull Dyes: Indane‐1,3‐Dione, 1H‐Cyclopenta[b]Naphthalene‐1,3(2H)‐Dione and 4‐Dimethoxyphenyl‐1‐Allylidene Derivatives

International audience; The free radical polymerization of acrylates photo-initiated by push–pull dye-based photoinitiating systems (PISs) is widely investigated in previous works. As a supplementary investigation on push–pull dyes, here in this article, 25 push–pull structures comprising electron acceptors derived from indane-1,3-dione and 1H-cyclopenta[b]naphthalene-1,3(2H)-dione (series 1) and 4-dimethoxyphenyl-1-allylidene moieties (series 2) and various electron donors are synthesized and examined as innovative structures for photoinitiation. Among the two series of dyes examined in this work and by monitoring the polymerization processes by RT-FTIR measurements, four dyes are determined as exhibiting excellent photoinitiation performances and these dyes are selected to perform further studies concerning the chemical mechanisms occurring inside the three-component PISs, for example, steady state photolysis, fluorescence quenching measurements, and cyclic voltammetry. Markedly, their reactivity is also proved by photoinitiation performance upon sunlight. These results prompt us to develop high performance push–pull dyes as photosensitizers and sunlight can be used as a mild and ecofriendly light source, which can advantageously replace LEDs for the free radical photopolymerization in the future. Finally, the formation of 3D patterns with an excellent gradient of resolution is successfully achieved by the direct laser write (DLW) with/without silica fillers.