Synthesis of star-shaped polyzwitterions with adjustable UCST and fast responsiveness by a facile RAFT polymerization

Li, Zhi; Li, Hao; Sun, Zhonghe; Hao, Botao; Lee, Tung‐Chun; Feng, Anchao; Zhang, Liqun; Thang, San H.

doi:10.1039/d0py00318b

Cited by 15 publications

(16 citation statements)

References 40 publications

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“…Therefore, amphiphilic polymers that preferentially form polymer–water hydrogen‐bonds (H‐bonds) may exhibit an LCST, [ 16–19 ] while polymers capable of forming stable polymer–polymer H‐bonds or ionic bonds may have a UCST. [ 20–23 ] Additionally, increasing the hydrophobicity of a TRP usually increase its UCST or decrease its LCST. [ 24–26 ]…”

Section: Methodsmentioning

confidence: 99%

Aqueous Synthesis of Upper Critical Solution Temperature and Lower Critical Solution Temperature Copolymers through Combination of Hydrogen‐Donors and Hydrogen‐Acceptors

et al. 2021

Macromol. Rapid Commun.

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The synthesis of thermo‐responsive polymers from non‐responsive and water‐soluble monomers has great practical advantages but significant challenges. Herein, the authors report a novel aqueous copolymerization strategy to prepare polymers with tunable upper critical solution temperature (UCST) or lower critical solution temperature (LCST) from non‐responsive monomers. Acrylic acid (AAc), N‐vinylpyrrolidone (NVP), and acrylamide (AAm) are copolymerized in water, yielding copolymers with UCST behavior. Interestingly, by simply replacing AAm with its methylated homologue, dimethyl acrylamide (DMA), the thermo‐responsiveness of the copolymers is converted into LCST‐type. The cloud points of the copolymers can be tuned rationally with their monomer ratios and the condition of the solvent. The UCST property of the poly(AAc–NVP–AAm) comes from the AAc–AAm and AAc–NVP hydrogen‐bonds, while the LCST property of poly(AAc–NVP–DMA) originates from the hydrophobic aggregation of AAc–NVP complex and DMA, as indicated by temperature‐dependent 1H NMR and dynamic light scattering.

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Section: Methodsmentioning

confidence: 99%

Aqueous Synthesis of Upper Critical Solution Temperature and Lower Critical Solution Temperature Copolymers through Combination of Hydrogen‐Donors and Hydrogen‐Acceptors

et al. 2021

Macromol. Rapid Commun.

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“…A star-shaped architecture represents a unique class of branched polymers consisting of a central core grafted with several polymer chains, which are forming so-called “arms” stretching into the surrounding solvent. While synthetic approaches for the formation of star polymers as well as their (self-)assembly into complex hierarchical topologies have been extensively studied in current research [ 309 ], the influence of branching on the thermoresponsive behavior of polymers is rarely considered [ 310 ]. While there are several studies for LCST star polymers (see Table 1 ), some of them are contradictory, the number of topological studies for UCST star polymers is very limited.…”

Section: Reviewmentioning

confidence: 99%

Constrained thermoresponsive polymers – new insights into fundamentals and applications

Flemming¹,

Münch²,

Fery³

et al. 2021

Beilstein J. Org. Chem.

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In the last decades, numerous stimuli-responsive polymers have been developed and investigated regarding their switching properties. In particular, thermoresponsive polymers, which form a miscibility gap with the ambient solvent with a lower or upper critical demixing point depending on the temperature, have been intensively studied in solution. For the application of such polymers in novel sensors, drug delivery systems or as multifunctional coatings, they typically have to be transferred into specific arrangements, such as micelles, polymer films or grafted nanoparticles. However, it turns out that the thermodynamic concept for the phase transition of free polymer chains fails, when thermoresponsive polymers are assembled into such sterically confined architectures. Whereas many published studies focus on synthetic aspects as well as individual applications of thermoresponsive polymers, the underlying structure–property relationships governing the thermoresponse of sterically constrained assemblies, are still poorly understood. Furthermore, the clear majority of publications deals with polymers that exhibit a lower critical solution temperature (LCST) behavior, with PNIPAAM as their main representative. In contrast, for polymer arrangements with an upper critical solution temperature (UCST), there is only limited knowledge about preparation, application and precise physical understanding of the phase transition. This review article provides an overview about the current knowledge of thermoresponsive polymers with limited mobility focusing on UCST behavior and the possibilities for influencing their thermoresponsive switching characteristics. It comprises star polymers, micelles as well as polymer chains grafted to flat substrates and particulate inorganic surfaces. The elaboration of the physicochemical interplay between the architecture of the polymer assembly and the resulting thermoresponsive switching behavior will be in the foreground of this consideration.

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“…Equally interesting is the work of Li and his team [ 94 ], who reported the synthesis of polyzwitterionic star-branched 3-dimethyl(methacryloyloxyethyl) ammonium propane sulfonate (DMAPS) moderated by a macro-RAFT agent bearing carboxylic end-group, in the presence of N , N -methylenebis(acrylamide) (MBA) crosslinker, via the “arm-first” approach. The star-shaped polymer exhibits dual thermo- and pH-responsiveness.…”

Section: 2 “Arm-first” Approachmentioning

confidence: 99%

Latest Advances on the Synthesis of Linear ABC-Type Triblock Terpolymers and Star-Shaped Polymers by RAFT Polymerization

et al. 2021

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This review article aims to cover the most recent advances regarding the synthesis of linear ABC-type triblock terpolymers and star-shaped polymers by RAFT polymerization, as well as their self-assembly properties in aqueous solutions. RAFT polymerization has received extensive attention, as it is a versatile technique, compatible with a great variety of functional monomers and reaction conditions, while providing exceptional and precise control over the final structure, with well-defined side-groups and post-polymerization engineering potential. Linear triblock terpolymers synthesis can lead to very interesting novel ideas, since there are countless combinations of stimuli/non-stimuli and hydrophilic/hydrophobic monomers that someone can use. One of their most interesting features is their ubiquitous ability to self-assemble in different nanostructures depending on their degree of polymerization (DP), block composition, solubilization protocol, internal and external stimuli. On the other hand, star-shaped polymers exhibit a more stable nanostructure, with a distinct crosslinked core and arm blocks that can also incorporate stimuli-responsive blocks for “smart” applications.

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Synthesis of star-shaped polyzwitterions with adjustable UCST and fast responsiveness by a facile RAFT polymerization

Abstract: We describe crosslinking of polyzwitterions for the formation of novel star-shaped polymers with low polydispersities and dual-responsiveness using RAFT polymerization.

Cited by 15 publications

References 40 publications

Aqueous Synthesis of Upper Critical Solution Temperature and Lower Critical Solution Temperature Copolymers through Combination of Hydrogen‐Donors and Hydrogen‐Acceptors

Aqueous Synthesis of Upper Critical Solution Temperature and Lower Critical Solution Temperature Copolymers through Combination of Hydrogen‐Donors and Hydrogen‐Acceptors

Constrained thermoresponsive polymers – new insights into fundamentals and applications

Latest Advances on the Synthesis of Linear ABC-Type Triblock Terpolymers and Star-Shaped Polymers by RAFT Polymerization

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