A.S. Quick, J. Fischer, B. Richter, Th. Pauloehrl, V. Trouillet, M. Wegener, and Ch. Barner-Kowollik

Macromol. Rapid Commun. 34, 335-340 (2013)

Abstract:

Three-dimensional microstructures are fabricated employing the direct laser writing process and radical thiol-ene polymerization. The resin system consists of a two-photon photoinitiator and multifunctional thiols and olefins. Woodpile photonic crystals with 22 layers and a rod distance of 2 μm are fabricated. The structures are characterized via scanning electron microscopy and focused ion beam milling. The thiol-ene polymerization during fabrication is verified via infrared spectroscopy. The structures are grafted in a subsequent thiol-Michael addition reaction with different functional maleimides. The success of the grafting reaction is evaluated via laser scanning microscopy and X-ray photoelectron spectroscopy. The grafting density is calculated to be close to 200 molecules μm⁻².