Angew:首例由光控“活性”聚合实现的普适性绿光控制 3D 及 4D 打印体系

Boyer Lab

2019-11-22

The Boyer laboratory at the Centrefor Advanced Macromolecular Design, UNSW Sydney, focuses on the synthesis offunctional polymers through photocontrolled polymerization processes. A newphotopolymerization technique, named photoinduced electron/energy transfer-reversible addition fragmentation chain transfer (PET-RAFT) polymerization wasdeveloped by the group in 2014¹ and has been widely applied forpolymer and material synthesis due to its high oxygen tolerance² andability to mediate polymerization under mild visible and near-infraredwavelength light.³ Major research themes in the group includecomputational photocatalyst design,⁴ synthetic antimicrobialpolymers,⁵ synthesis of polymeric nanoparticles,⁶ photo-flowpolymerization, and more recently, 2D,⁷ 3D and 4D printing.⁸

澳大利亚新南威尔士大学先进高分子材料设计中心 Cyrille Boyer 教授课题组（boyerlab.com）长期致力于发展基于光控“活性”聚合的多种功能性高分子材料合成方法。课题组于 2014 年提出一种新的可见光控“活性”聚合方法，即photoinducedelectron/energy transfer- reversible addition fragmentation chain transfer(PET-RAFT) polymerisation 聚合方法。¹此后，PET-RAFT 聚合因杰出的氧气耐受性²及广谱可见光、甚至近红外光下的可控性而在多种聚合物基材料合成场景中得到广泛应用。³课题组近年主要研究领域包括计算机指导光催化剂设计、⁴抗菌高分子材料合成、⁵聚合物基纳米材料合成、⁶可见光控流动聚合反应釜以及新近发展的绿光可控聚合  2D、⁷ 3D 及 4D 打印方法（本文）。⁸

3D printing techniques provide simplifiedavenues to producing geometrically complex materials while reducing waste. Typically,objects made from polymeric (plastic) materials cannot be manipulated after 3Dprinting as the polymerisation process results in “dead” polymer chains thatcannot be reactivated. As a result, 3D printed materials are monofunctional andnon-recyclable, which limits potential functionalisation. Furthermore,traditional 3D printing systems use harsh toxic chemicals and harmful UV lightsources, decreasing the safety and potential applicability to biologicalsystem.

3D 打印技术为结构复杂的材料用具制造提供了大为简化且经济实用的途径。然而，由于传统自由基聚合结束后的链终止效应，由聚合物反应制备的材料在 3D 打印完成后无法恢复活性，进而无法继续生长制备。因此，现存 3D 打印技术制备的聚合物基材料通常仅具有单一功能且难以回收再用；这一局限性为材料的功能化发展带来瓶颈。与此同时，传统的光 3D 打印体系普遍采用严苛且具毒性的环境及对人体有潜在伤害的紫外光源；这一弱点使其尚存一定安全隐患且限制了在生物医学环境中的应用。

来自新南威尔士大学 Boyer 实验室（boyerlab.com）的ZhihengZhang、Nathaniel Corrigan博士及Cyrille Boyer 教授等，报道了一项将“活性”聚合普适地应用入 3D （ZhangZ., Corrigan N., Bagheri A., Jin J., Boyer C., Angew. Chem. Int. Ed. 2019. https://doi.org/10.1002/anie.201912608）。本文中实现的光介导控制的“活性”3D 打印（基于 Boyer 实验室开发的 PET-RAFT 聚合技术）采用无毒无金属的水相纯有机，并采用安全无害的绿光单色光源。RAFT 试剂的引入将“活性”聚合特征赋予该法制造的聚合物基材料，并由于聚合的高度可控性，使得精准调控材料的诸如强韧性和弹性等各项机械性能得以实现。该法制备的 3D 打印聚合物产品，由于全由具活性末端的高分子链组成，可直接在制造完成后轻易进行功能化修饰或进行继续生长制备，并由此通过 3D 打印制造出同时具有复杂结构及可调的优异物理化学性质的物体。

The 3D printed material was initially hydrophilic (top left) but after modifyingthe surface through “living” polymerization, the material became hydrophobic(bottom left). Using visible light also allowed the modification of the 3Dprinted material be spatially controlled (left).

Additionally, by controllingthe light irradiation 4D printed materials (3D printed materials that respondto an external stimulus) were formed, as demonstrated by 3D printed objectsthat reversibly folded when exposed to water. As such, this photocontrolledRAFT 3D and 4D printing system will facilitate the development of functionaland stimuli-responsive 3D printed materials. Furthermore, as the reactioncomponents are non-toxic and can be polymerized under harmless visible light,these systems should be used in the future for varied applications, includingnanomedicine and other bioapplications.

另外，通过采用这种方法进行 4D 打印（即在 3D 打印的基础上额外增加材料对于外界环境的响应 ） ，实现了对所打印 3D 物体的在遇水后的可逆折叠行为。因此，这项工作中所发展的绿光可控 RAFT 聚合基, 3D 及 4D  打印系统将为功能化及响应性 3D 打印新材料的发展提供可观的助力。而由于该体系中牵涉的反应组分及环境及绿单色光源均为无毒无害且生物友好，该种方法有望开拓 3D、4D 打印在纳米医学、生物医学等众多领域中的应用。

The 3D printed materials were able to change their shape on exposure to water. Thepicture shows a 3D printed cross shaped material swelling with water (top left)-after being flipped (top right), the cross flattened (bottom right) and then invertedits arch as it dried (bottom right).

参考文献

Zhang Z, Corrigan N, Bagheri A,et al. A Versatile 3D and 4D Printing System through Photocontrolled RAFTPolymerization. Angewandte Chemie, 2019.

DOI:10.1002/ange.201912608

https://onlinelibrary_wiley.xilesou.top/doi/abs/10.1002/ange.201912608

References
1. A robust and versatile photoinduced living polymerization of conjugated andunconjugated monomers and its oxygen tolerance, J. Xu, K. Jung, A. Atme, S.Shanmugam, C. Boyer (2014) Journal of the American Chemical Society 136 (14),5508-5519

2. Effective utilization of NIRwavelengths for photo‐controlledpolymerization–penetrationthrough thick barriers and parallel solar syntheses (2019) Z. Wu, K. Jung, C.Boyer Angewandte Chemie International Edition, DOI: https://doi.org/10.1002/anie.201912484

3. a) Oxygen Tolerance inLiving Radical Polymerization: Investigation of Mechanism and Implementation inContinuous Flow Polymerization (2016) N. Corrigan, D. Rosli, J.W.J. Jones, J.Xu, C. Boyer Macromolecules 49 (18), 6779-6789; b) An Oxygen Paradox: CatalyticUse of Oxygen in Radical Photopolymerization (2019) L. Zhang, C. Wu, K. Jung,Y.H. Ng, C. Boyer, Angewandte Chemie, https://doi.org/10.1002/ange.201909014

4. Computer-Guided Discovery ofa pH-Responsive Organic Photocatalyst and Application for pH and LightDual-Gated Polymerization (2019) C. Wu, H. Chen, N. Corrigan, K. Jung, X. Kan,Z. Li, W. Liu, J. Xu, C.  Boyer Journalof the American Chemical Society, 141, 20, 8207-8220

5. Towards Sequence‐ControlledAntimicrobial Polymers: Effect of Polymer Block Order on Antimicrobial Activity(2018) P.R. Judzewitsch, T.K. Nguyen, S. Shanmugam, E.H.H. Wong, C. BoyerAngewandte Chemie 130 (17), 4649-4654

6. Photoinitiated Polymerization‐InducedSelf‐Assembly (Photo‐PISA):New Insights and Opportunities (2017) J Yeow, C Boyer, Advanced Science 4 (7),1700137

7. SI-PET-RAFT:Surface-Initiated Photoinduced Electron Transfer-ReversibleAddition–Fragmentation Chain Transfer Polymerization (2019) M. Li, M. Fromel, D.Ranaweera, S. Rocha, C. Boyer, C.W. Pester, ACS Macro Letters 8 (4), 374-380

8. A Versatile 3D and 4DPrinting System through Photocontrolled RAFT Polymerization (2019) Zhang Z.,Corrigan N., Bagheri A., Jin J., Boyer C., Angew. Chem. Int. Ed. 2019. https://doi.org/10.1002/anie.201912608

通讯作者简介

Cyrille Boyer received his PhD from the University of Montpellier II. In 2006, he joined the Centre forAdvanced Macromolecular Design and was promoted to full Professor at UNSW in2016. He received several awards, including one of the six Prime MinisterPrizes for Science (Malcolm MacIntosh Prize) in 2015, ACSBiomacromolecules/Macromolecules Young Investigator Award in 2016 and PolymerInternational – IUPAC award in 2018. In 2018, he was listed as Highly CitedResearcher by Clarivate (Web of Science). His research interests cover the useof photoredox catalysts, polymers for bioapplications and energy storage.

Nathaniel Corrigan received hisPhD in Chemical Engineering under the supervision of Prof Cyrille Boyer at UNSWSydney, Australia in 2019. His PhD thesis focussed on the combination ofvisible light mediated reversible deactivation radical polymerization (RDRP)and flow chemistry for advanced macromolecular synthesis.He is currently a research associate at UNSW Sydney where his research focuseson exploiting visible light for controlled radical polymerization, flowchemistry, and materials synthesis via 3D printing approaches.