TY - JOUR AU - Li, Zhiquan AU - Pucher, Niklas AU - Cicha, Klaus AU - Torgersen, Jan AU - Ligon, Samuel C. AU - Ajami, Aliasghar AU - Husinsky, Wolfgang AU - Rosspeintner, Arnulf AU - Vauthey, Eric AU - Naumov, Sergej AU - Scherzer, Tom AU - Stampfl, Jürgen AU - Liska, Robert TI - A Straightforward Synthesis and Structure-Activity Relationship of Highly Efficient Initiators for Two-Photon Polymerization PY - 2013 JF - Macromolecules JA - Macromolecules SN - 0024-9297 VL - 46 IS - 2 SP - 352 EP - 361 L1 - http://pubs.acs.org/doi/pdf/10.1021/ma301770a L2 - http://pubs.acs.org/doi/full/10.1021/ma301770a L3 - http://pubs.acs.org/doi/abs/10.1021/ma301770a M3 - 10.1021/ma301770a UR - http://dx.doi.org/10.1021/ma301770a N2 - The development of practical two-photon absorption photoinitiators (TPA PIs) has been slow due to their complicated syntheses often reliant on expensive catalysts. These shortcomings have been a critical obstruction for further advances in the promising field of two-photon-induced photopolymerization (TPIP) technology. This paper describes a series of linear and cyclic benzylidene ketone-based two-photon initiators containing double bonds and dialkylamino groups synthesized in one step via classical aldol condensation reactions. Systematic investigations of structure–activity relationships were conducted via quantum-chemical calculations and experimental tests. These results showed that the size of the central ring significantly affected the excited state energetics and emission quantum yields as well as the two-photon initiation efficiency. In the TPIP tests the 4-methylcyclohexanone-based initiator displayed much broader ideal processing windows than its counterparts with a central five-membered ring and previously described highly active TPA PIs. Surprisingly, a writing speed as high as 80 mm/s was obtained for the microfabrication of complex 3D structures employing acrylate-based formulations. These highly active TPA PIs also exhibit excellent thermal stability and remain inert to one-photon excitation. Straightforward synthesis combined with high TPA initiation efficiency makes these novel initiators promising candidates for commercialization. ID - 1336 ER -