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
澳大利亞新南威爾士大學先進高分子材料設計中心 Cyrille Boyer 教授課題組（boyerlab.com）長期致力于發展基于光控“活性”聚合的多種功能性高分子材料合成方法。課題組于 2014 年提出一種新的可見光控“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 聚合因杰出的氧氣耐受性2及廣譜可見光、甚至近紅外光下的可控性而在多種聚合物基材料合成場景中得到廣泛應用。3課題組近年主要研究領域包括計算機指導光催化劑設計、4抗菌高分子材料合成、5聚合物基納米材料合成、6可見光控流動聚合反應釜以及新近發展的綠光可控聚合 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 打印技術為結構復雜的材料用具制造提供了大為簡化且經濟實用的途徑。然而，由于傳統自由基聚合結束后的鏈終止效應，由聚合物反應制備的材料在 3D 打印完成后無法恢復活性，進而無法繼續生長制備。因此，現存 3D 打印技術制備的聚合物基材料通常僅具有單一功能且難以回收再用；這一局限性為材料的功能化發展帶來瓶頸。與此同時，傳統的光 3D 打印體系普遍采用嚴苛且具毒性的環境及對人體有潛在傷害的紫外光源；這一弱點使其尚存一定安全隱患且限制了在生物醫學環境中的應用。
來自新南威爾士大學 Boyer 實驗室（boyerlab.com）的ZhihengZhang、Nathaniel Corrigan博士及Cyrille Boyer 教授等，報道了一項將“活性”聚合普適地應用入 3D （ZhangZ., Corrigan N., Bagheri A., Jin J., Boyer C., Angew. Chem. Int. Ed. 2019. https://doi.org/10.1002/anie.201912608）。本文中實現的光介導控制的“活性”3D 打?。ɑ?Boyer 實驗室開發的 PET-RAFT 聚合技術）采用無毒無金屬的水相純有機，并采用安全無害的綠光單色光源。RAFT 試劑的引入將“活性”聚合特征賦予該法制造的聚合物基材料，并由于聚合的高度可控性，使得精準調控材料的諸如強韌性和彈性等各項機械性能得以實現。該法制備的 3D 打印聚合物產品，由于全由具活性末端的高分子鏈組成，可直接在制造完成后輕易進行功能化修飾或進行繼續生長制備，并由此通過 3D 打印制造出同時具有復雜結構及可調的優異物理化學性質的物體。
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，通過采用這種方法進行 4D 打?。丛?3D 打印的基礎上額外增加材料對于外界環境的響應 ） ，實現了對所打印 3D 物體的在遇水后的可逆折疊行為。因此，這項工作中所發展的綠光可控 RAFT 聚合基, 3D 及 4D 打印系統將為功能化及響應性 3D 打印新材料的發展提供可觀的助力。而由于該體系中牽涉的反應組分及環境及綠單色光源均為無毒無害且生物友好，該種方法有望開拓 3D、4D 打印在納米醫學、生物醫學等眾多領域中的應用。
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).
參考文獻
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
通訊作者簡介
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.
