Silyl-based initiators for two-photon polymerization: from facile synthesis to quantitative structure–activity relationship analysis

Li, Zhiquan; Rosspeintner, Arnulf; Hu, Peng; Zhu, Guigang; Hu, Yuan-Sheng; Xiong, Xiang; Peng, Ru‐Wen; Wang, Mu; Liu, Xiaoya; Liu, Ren

doi:10.1039/c7py01360d

Cited by 16 publications

(11 citation statements)

References 54 publications

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“…To promote two‐photon 3D printing into the market, development of efficient two‐photon initiators (2PIs), a key compound in photoactive formulations, is highly desirable to guarantee fast printing rates, a reduced polymerization threshold, and finally fabricated structures with a high resolution . An efficient 2PI should have large two‐photon absorption (2PA) to ensure efficient photon absorption, and an efficient initiation mechanism, through which the absorbed energy can be efficiently used to generate active initiation species . To date, the free radical initiation mechanism for two‐photon polymerization has mainly been based on intermolecular electron transfer.…”

Section: Methodsmentioning

confidence: 99%

Cleavable Unimolecular Photoinitiators Based on Oxime‐Ester Chemistry for Two‐Photon Three‐Dimensional Printing

Qiu

Zhu

et al. 2019

ChemPhotoChem

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The development of efficient two-photon initiators (2PIs) is critical to promote two-photon three-dimensional (3D) printing for market applications. On the basis of the photocleavage concept, several unimolecular 2PIs that contain coumarin moieties (as two-photon absorption chromophores) and oximeester groups (as initiation functional groups) were synthesized. Under visible light irradiation, the investigated oxime-esters, sensitive to a broad wavelength range from 400 to 460 nm, undergo direct photocleavage followed by decarboxylation, forming active free radicals to effectively induce polymerization. Interestingly, the photoinitiators exhibit good photobleaching properties, which makes them applicable for photopolymerization of thick materials and dental restorative materials. In twophoton 3D printing tests with acrylate formulations, the oximeester derivatives were used to build complex 3D microstructures with submicrometer or even nanometer spatial resolution. The initiator comprised of a conjugated coumarin and an oxime ester attached at the 3-position exhibited a low threshold laser power required for polymerization and had a broad processing window similar to a highly efficient 2PI in the literature.

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Section: Methodsmentioning

confidence: 99%

Cleavable Unimolecular Photoinitiators Based on Oxime‐Ester Chemistry for Two‐Photon Three‐Dimensional Printing

Qiu

Zhu

et al. 2019

ChemPhotoChem

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“…Fine microstructures can be printed out at a laser intensity of ∼15 mW when using the commercial two‐photon resists IP‐L (Figure a). High resolution combined with good mechanical stability has been reported for this liquid negative‐tone photoresist based on sol‐gel chemistry . But the unknown composition of such premixed commercial photoresists limits the degree of formulation adjustment.…”

Section: Resultsmentioning

confidence: 99%

Conjugated Bifunctional Carbazole‐Based Oxime Esters: Efficient and Versatile Photoinitiators for 3D Printing under One‐ and Two‐Photon Excitation

Qiu

Naumov

et al. 2020

ChemPhotoChem

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The rapid development of 3D printing using visible light as an irradiation source requires efficient visible light photoinitiators to realize a fast and reliable 3D printing process. Based on the photocleavage concept, a series of symmetric bifunctional photoinitiators comprising oxime‐ester moieties as latent initiation functionalities and conjugated carbazole as chromophores was synthesized. The impact of substitution position and the types of radicals on photophysical and photochemical behavior was investigated via experimental tests combined with quantum‐chemical calculations. The conjugated carbazole‐based oxime esters exhibit broad absorption bands from 250 to 400 nm and an interesting photobleaching property was observed during photolysis. Under 405 nm LED irradiation, the photoinitiation efficiency of the novel photoinitiators is comparable to that of the commercial visible light photoinitiator TPO. A vertical resolution of 50 μm was obtained when using oxime esters as photoinitiators in DLP 3D printing to fabricate delicate objects. The A‐π‐D‐π‐A core structures impart sufficient two‐photon cross sections (102–136 GM) to the oxime esters, enabling the construction of complex 3D microstructures of nanometer spatial resolution with two‐photon 3D printing technology. Notably, the threshold energy of the formulation containing 4d is lower than that of the commercial two‐photon resists IP−L. Also, the thermal stability of the PIs (>160 °C) is sufficient for daily storage.

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“…2PP is a growing technological area but is yet to fully unleash its potential; as such, a comprehensive understanding of how the printing parameters impact upon the polymerization process is required. The specific choice of initiator is important in this respect and a number of novel 2PP initiators have been used recently to both achieve enhanced two-photon activity [2,7] and/or manipulate the final properties of the printed structures [8,9]. Optimization of the printing parameters and deposition strategy provides additional control of material properties and is of key importance in achieving control of functionality.…”

Section: Introductionmentioning

confidence: 99%

The influence of printing parameters on multi-material two-photon polymerisation based micro additive manufacturing

Rance

Trindade

et al. 2022

Additive Manufacturing

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Silyl-based initiators for two-photon polymerization: from facile synthesis to quantitative structure–activity relationship analysis

Abstract: Silyl-based stilbene derivatives were straightforwardly prepared and successfully applied in two photon lithography as photoinitiators.

Cited by 16 publications

References 54 publications

Cleavable Unimolecular Photoinitiators Based on Oxime‐Ester Chemistry for Two‐Photon Three‐Dimensional Printing

Cleavable Unimolecular Photoinitiators Based on Oxime‐Ester Chemistry for Two‐Photon Three‐Dimensional Printing

Conjugated Bifunctional Carbazole‐Based Oxime Esters: Efficient and Versatile Photoinitiators for 3D Printing under One‐ and Two‐Photon Excitation

The influence of printing parameters on multi-material two-photon polymerisation based micro additive manufacturing

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