Chemical and Biomolecular Engineering - Research Publications
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ItemNo Preview AvailableHigh chain-end fidelity in sono-RAFT polymerization(Royal Society of Chemistry, 2022-10-15)The chain-end fidelity of polymers synthesized via the sono-RAFT technique in an aqueous medium was investigated by performing chain extension studies and preparation of multi-block copolymers. Sono-RAFT polymerization of N,N-dimethylacrylamide (DMA), 2-hydroxyethyl acrylate (HEA) and N-acryloyl morpholine (NAM) exhibited higher conversion values, low dispersity and excellent chain-end fidelity. MALDI-TOF analysis indicated that the fraction of dead chains observed was almost negligible indicating high livingness of the polymer end groups. The sono-RAFT technique was compared to the photo-iniferter method by performing chain extension experiments. Polymers prepared via sono-RAFT were identical to those prepared via the photo-iniferter RAFT method in terms of livingness, and the polymer reached very high conversion within a fraction of the time compared to the latter method. An icosapenta block copolymer (25 blocks) was synthesized at room temperature within 46 h. The resulting block copolymer displayed a controlled molecular weight and a final dispersity of 1.39.
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ItemFrom UV to NIR: A Full-Spectrum Metal-Free Photocatalyst for Efficient Polymer Synthesis in Aqueous Conditions(WILEY-V C H VERLAG GMBH, 2020-11-23)Photo-mediation offers unparalleled spatiotemporal control over controlled radical polymerizations (CRP). Photo-induced electron/energy transfer reversible addition-fragmentation chain transfer (PET-RAFT) polymerization is particularly versatile owing to its oxygen tolerance and wide range of compatible photocatalysts. In recent years, broadband- and near-infrared (NIR)-mediated polymerizations have been of particular interest owing to their potential for solar-driven chemistry and biomedical applications. In this work, we present the first example of a novel photocatalyst for both full broadband- and NIR-mediated CRP in aqueous conditions. Well-defined polymers were synthesized in water under blue, green, red, and NIR light irradiation. Exploiting the oxygen tolerant and aqueous nature of our system, we also report PET-RAFT polymerization at the microliter scale in a mammalian cell culture medium.
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ItemFrom UV to NIR: A Full-Spectrum Metal-Free Photocatalyst for Efficient Polymer Synthesis in Aqueous Conditions(Wiley, 2020-01-01)Abstract Photo‐mediation offers unparalleled spatiotemporal control over controlled radical polymerizations (CRP). Photo‐induced electron/energy transfer reversible addition–fragmentation chain transfer (PET‐RAFT) polymerization is particularly versatile owing to its oxygen tolerance and wide range of compatible photocatalysts. In recent years, broadband‐ and near‐infrared (NIR)‐mediated polymerizations have been of particular interest owing to their potential for solar‐driven chemistry and biomedical applications. In this work, we present the first example of a novel photocatalyst for both full broadband‐ and NIR‐mediated CRP in aqueous conditions. Well‐defined polymers were synthesized in water under blue, green, red, and NIR light irradiation. Exploiting the oxygen tolerant and aqueous nature of our system, we also report PET‐RAFT polymerization at the microliter scale in a mammalian cell culture medium.
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ItemProgress and Perspectives Beyond Traditional RAFT Polymerization(Wiley, 2020-10-21)The development of advanced materials based on well‐defined polymeric architectures is proving to be a highly prosperous research direction across both industry and academia. Controlled radical polymerization techniques are receiving unprecedented attention, with reversible‐deactivation chain growth procedures now routinely leveraged to prepare exquisitely precise polymer products. Reversible addition‐fragmentation chain transfer (RAFT) polymerization is a powerful protocol within this domain, where the unique chemistry of thiocarbonylthio (TCT) compounds can be harnessed to control radical chain growth of vinyl polymers. With the intense recent focus on RAFT, new strategies for initiation and external control have emerged that are paving the way for preparing well‐defined polymers for demanding applications. In this work, the cutting‐edge innovations in RAFT that are opening up this technique to a broader suite of materials researchers are explored. Emerging strategies for activating TCTs are surveyed, which are providing access into traditionally challenging environments for reversible‐deactivation radical polymerization. The latest advances and future perspectives in applying RAFT‐derived polymers are also shared, with the goal to convey the rich potential of RAFT for an ever‐expanding range of high‐performance applications.