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ABSTRACT New methacrylate monomers with carbazole moieties as pendant groups were synthesized by multistep syntheses starting from carbazoles with biphenyl substituents in the aromatic ring. The corresponding polymers were prepared using a free‐radical polymerization. The novel polymers containN‐alkylated carbazoles mono‐ or bi‐substituted with biphenyl groups in the aromatic ring.N‐alkyl chains in polymers vary by length and structure. All new polymers were synthesized to evaluate the structural changes in terms of their effect on the energy profile, thermal, dielectric, and photophysical properties when compared to the parent polymer poly(2‐(9H‐carbazol‐9‐yl)ethyl methacrylate). According to the obtained results, these compounds may be well suited for memory resistor devices. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem.2019, 57, 70–76
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Tailored thioxanthone‐based photoinitiators for two‐photon‐controllable polymerization and nanolithographic printing
ABSTRACT Printing of high‐resolution three‐dimensional nanostructures utilizing two‐photon polymerization has gained significant attention recently. In particular, isopropyl thioxanthone (ITX) has been implemented as a photoinitiator due to its capability of initiating and depleting polymerization on demand, but new photoinitiating materials are still needed in order to reduce the power requirements for the high‐throughput creation of 3D structures. To address this point, a suite of new thioxanthone‐based photoinitiators were synthesized and characterized. Then two‐photon polymerization was performed using the most promising photoinitiating molecule. Importantly, one of the initiators, 2,7‐bis[(4‐(dimethylamino)phenyl ethynyl)‐9H‐thioxanthen‐9‐one] (BDAPT), showed a fivefold improvement in the writing threshold over the commonly used ITX molecule. To elucidate the fundamental mechanism, the excitation and inhibition behavior of the BDAPT molecule were evaluated using density functional theory (DFT) calculations, low‐temperature phosphorescence spectroscopy, ultra‐fast transient absorption spectroscopy, and the two‐photon Z‐scan spectroscopic technique. The improved polymerization threshold of this new photoinitiator presents a clear pathway for the modification of photoinitiators in 3D nanoprinting. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys.2019,57, 1462–1475
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- Award ID(s):
- 1634832
- PAR ID:
- 10459331
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Journal of Polymer Science Part B: Polymer Physics
- Volume:
- 57
- Issue:
- 21
- ISSN:
- 0887-6266
- Page Range / eLocation ID:
- p. 1462-1475
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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