Reversible-addition fragmentation chain transfer (RAFT) polymerization has been widely explored since its discovery due to its structural precision, versatility, and efficiency. However, the lack of tunability of the polymer backbone limits some applications. Herein, we synergistically combine RAFT and step-growth polymerization mechanisms, by employing a highly selective insertion process of a single monomer with a RAFT agent, to achieve RAFT step-growth polymerization. A unique feature of the RAFT step-growth polymers is that each backbone repeat unit bears a pendant RAFT agent, which can subsequently graft side chains in a second polymerization step and afford molecular brush polymers. Enabled by cleavable backbone functionality, we demonstrate transformation of the resulting brushlike polymers into linear chains of uniform size upon a stimulus.

The in situ one-pot synthesis of peptide-polymer bioconjugates is reported. Conjugation occurs efficiently without the need for purification of dithiophenol maleimide functionalized polymer as a disulfide bridging agent for the therapeutic oxytocin. Conjugation of polymers was demonstrated to be reversible and to significantly improve the solution stability of oxytocin.

copolymers (MBCPs) are emerging class of materials that are becoming more accessible in recent years. However, to date there is still a lack of fundamental understanding of their physical properties. In particular, the glass transition temperature (Tg) which is known to be affected by the phase separation has not been well characterised experimentally. To this end, we report the first experimental study on the evolution of the Tgs and the corresponding phase separation of linear MBCPs with increasing number of blocks whilst keeping the overall degree of polymerisation (DP) constant (DP = 200). Ethylene glycol methyl ether acrylate (EGMEA) and tert-butyl acrylate (tBA) were chosen as monomers for reversible addition-fragmentation chain transfer polymerization to synthesise MBCPs. We found the Tgs (as measured by Differential Scanning Calorimetry) of EGMEA and tBA segments within the MCBPs to converge with increasing number of blocks and decreasing block length, correlating with the loss of the heterogeneity as observed from Small Angel X-ray Spectroscopy (SAXS) analysis. The Tgs of the multiblock copolymers were also compared to the Tgs of the polymer blends of the corresponding homopolymers, and we found that Tgs of the polymer blends were similar to those of the respective homopolymers, as expected. SAXS experiments further demonstrated microphase separation of multiblock copolymers. This work demonstrates the enormous potential of multiblock architectures to tune the physical properties of synthetic polymers, by changing their glass transition temperature and their morphologies obtained from microphase separation, with domain sizes reaching under 10 nm.

A series of polymer micelles with a perfluorocarbon (PFC) core to carry both PS and O2 to tumor sites was prepared. These new PFC formulation not only improved the production of 1O2 and enhanced the PDT efficiency, but also significantly reduced cell toxicity compared with the one without a perfluoro unit.

Synthesis of long-chain hyperbranched poly(ethylenimine-co-oxazoline)s by AB2 thiol–yne chemistry is reported, and their application as pDNA transfection agents studied.

An orthogonal combination of cationic and radical RAFT polymerizations is used to synthesize bottlebrush polymers using two distinct RAFT agents. Selective consumption of the first RAFT agent is used to control the cationic RAFT polymerization of a vinyl ether monomer bearing a secondary dormant RAFT agent, which subsequently allows side-chain polymers to be grafted from the pendant RAFT agent by a radical-mediated RAFT polymerization of a different monomer, thus completing the synthesis of bottlebrush polymers. The high efficiency and selectivity of the cationic and radical RAFT polymerizations allow both polymerizations to be conducted in one-pot tandem without intermediate purification. Reversible addition-fragmentation chain-transfer (RAFT)has grown in the last 20 years as one of the most versatile polymerization techniques, enabling the control of molecular weight distribution, branched architecture, and chemical functionality for a wide range of polymeric systems. [1] Based on the RAFT versatility, recent years have seen an expansion of using various RAFT agents beyond traditional thermally initiated radical polymerizations. [2] One emerging direction is the use of RAFT agents that facilitate other classes of polymerization such as anionic ring-opening polymerization (AROP) [3] and cationic RAFT polymerization, [4] in synergy with radical mediated RAFT polymerization, to enable dual copolymerization strategies [4b,d, 5] and access unique copolymer compositions. [3c, 4b] Another emerging research area is the exploitation of the versatile photochromic behavior of RAFT agents for photo-controlled polymerization upon direct photo-fragmentation of the R-group of the RAFT agent by UV/Vis irradiation (following the iniferter mechanism) [6] or through a photocatalyst (photoinduced-electron/energy transfer). [7] In particular, Xu and Boyer demonstrated the wavelength dependency of selectively photo-activated RAFT agents [6b, 8] to allow selective RAFT control for orthogonal polymerizations, where an unselected yet activatable RAFT agent remains dormant during photo-controlled radical polymerization with another RAFT agent. [9] Such selective RAFT processes had been previously untapped owing to inherent difficulties in suppressing chain transfer activity of reactive RAFT agents. [10] Through selective photo-fragmentation, Matyjaszewski, Boyer, and co-workers elegantly demonstrated an orthogonal iniferter-RAFT polymerization. [9b] In their case (Figure 1 a), a RAFT-agent-bearing methacrylate monomer was first polymerized orthogonally to produce a linear polymeric chain with pendant RAFT agents remaining intact during the polymerization of the methacrylate unit. The pendant RAFT Figure 1. Generalized structure of a RAFT agent and comparison of two-step syntheses of bottlebrush macromolecules via orthogonal RAFT in a) previous work [9b] and b) this work.

Here, commercially available N-aromatic substituted bismaleimides were used in RAFT step-growth polymerization for the first time. In our initial report (J. Am. Chem. Soc. 2021, 143 (39), 15918-15923), maleimide precursors...

Sébastien. (2017) Self-assembly and dis-assembly of stimuli responsive tadpole-like single chain nanoparticles using a switchable hydrophilic/hydrophobic boronic acid cross-linker. Polymer Chemistry, 28 (8). pp. 4079-4087. Permanent WRAP URL:http://wrap.warwick.ac.uk/93551 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for-profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP URL' above for details on accessing the published version and note that access may require a subscription. Living systems are driven by molecular machines that are composed of folded polypeptide chains, which are assembled together to form a multimeric complex. Although replicating this type of systems is a long standing goal in polymer science, the complexity of the structures imposes is synthetically very challenging, and generating synthetic polymers to mimic the process of these assemblies appears to be a more appealing approach. To this end, we report a linear polymer programmable for stepwise folding and assembly to higher-order structures. To achieve this, a diblock copolymer composed of 4-Acryloylmorpholine and glycerol acrylate was synthesised with high precision via reversible addition fragmentation chain transfer polymerisation (Ð < 1.22). Both intramolecular folding and intermolecular assembly was driven by pH responsive cross-linker, benzene-1,4-diboronic acid. The resulting intramolecular folded single chain nanoparticles were well defined (Ð < 1.16) and successfully assembled into a multimeric structure (Dh = 245 nm) at neutral pH with no chain entanglement. The assembled multimer was observed with a spherical morphology as confirmed by TEM and AFM. These structures were capable of unfolding and disassembling either at low pH or in the presence of sugar. This work offers new perspective for the generation of adaptive smart materials.