Influence of UV irradiation and two photon processing on the cinnamate monomers polymerization and formation of hybrid composites with nanosized ZnO

In a first part, N,N-bis(methacryloyloxyethyl carbamoyloxyethyl) cinnamamide (Cin-DMA) and its corresponding oligocinnamate were synthesized and used as organic matrix for preparing hybrid nanocomposites containing siloxane structure derived from urea-silyl monomer, PEG400 sequences and ZnO nanoparticles upon exposure to UV irradiation or femtosecond laser beam. 1H NMR, 13C NMR and FTIR spectroscopies sustain the expected structure, and the photopolymerization progress of Cin-DMA relating to a oligodimethacrylate alone and in combination with the hybrid monomer was investigated by photo-DSC, the time to reach the maximum polymerization heat (tmax), the degree of conversion (DC) and polymerization rate being determined. The photopolymerization results revealed that the investigated monomers exhibit a good photoreactivity (DC: 57–81%) during the formation of crosslinked polymers, and the degree of conversion depend especially on the chemical structure, photoinitiator nature (Darocur TPO, Irgacure 369) and its concentration. Incorporation of 0.5 or 1 wt.% spherical-shaped ZnO nanoparticles (average diameter: 50–100 nm; height: 50 nm) slightly decreased the polymerization rate from 0.08 to 0.068 s−1, respectively. Additionally, two-photon photopolymerization of cinnamate monomers alone and in monomer mixture in the presence or the absence of ZnO nanoparticles (0.5–2 wt.%) has been used in creating 2D and 3D polymeric microstructures via direct laser writing process by femtosecond laser pulse visible-light beams, whose morphology and fluorescence properties were explored to further exploit the new possibilities of micro/nanostructuring technology of the last fluorescent scaffolds.