A Straightforward Synthesis and Structure-Activity Relationship of Highly Efficient Initiators for Two-Photon Polymerization

作者：Li Zhiquan; Pucher Niklas; Cicha Klaus; Torgersen Jan; Ligon Samuel C; Ajami Aliasghar; Husinsky Wolfgang; Rosspeintner Arnulf; Vauthey Eric; Naumov Sergej; Scherzer Tom; Stampfl Juergen; Liska Robert^*

来源：Macromolecules, 2013, 46(2): 352-361.

DOI：10.1021/ma301770a

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.

• 出版日期2013-1-22