scholarly journals Lanthanoids Goes Healing: Lanthanoidic Metallopolymers and Their Scratch Closure Behavior

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 838
Author(s):  
Stefan Götz ◽  
Stefan Zechel ◽  
Martin D. Hager ◽  
Ulrich S. Schubert

Metallopolymers represent an interesting combination of inorganic metal complexes and polymers resulting in a variety of outstanding properties and applications. One field of interest are stimuli-responsive materials and, in particular, self-healing polymers. These systems could be achieved by the incorporation of terpyridine–lanthanoid complexes of Eu (III), Tb (III), and Dy (III) in the side chains of well-defined copolymers, which were prepared applying the reversible addition fragmentation chain-transfer (RAFT)-polymerization technique. The metal complexes crosslink the polymer chains in order to form reversible supramolecular networks. These dynamics enable the self-healing behavior. The information on composition, reversibility, and stability of the complexes was obtained by isothermal titration calorimetry (ITC). Moreover, self-healing experiments were performed by using 3D-microscopy and indentation.

2021 ◽  
Author(s):  
Siva Ponnupandian ◽  
Prantik Mondal ◽  
Thomas Becker ◽  
Richard Hoogenboom ◽  
Andrew B Lowe ◽  
...  

This investigation reports the preparation of a tailor-made copolymer of furfuryl methacrylate (FMA) and trifluoroethyl methacrylate (TFEMA) via reversible addition-fragmentation chain transfer (RAFT) polymerization. The furfuryl groups of the copolymer...


Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 487
Author(s):  
Yusheng Liu ◽  
Yigang Liu ◽  
Qiuxia Wang ◽  
Yugui Han ◽  
Hao Chen ◽  
...  

The incorporation of double dynamic bonds into hydrogels provides an effective strategy to engineer their performance on demand. Herein, novel hydrogels were PREPARED by combining two kinetically distinct dynamic covalent bonds, boronate ester and acylhydrazone bonds, and the synergistic properties of the hydrogels were studied comprehensively. The functional diblock copolymers P(N-isopropyl acrylamide-co-N-acryloyl-3-aminophenylboronic acid)-b-(N-isopropyl acrylamide-co-diacetone acrylamide) (PAD) were prepared via reversible addition−fragmentation chain transfer (RAFT) polymerization. The hydrogel was constructed by exploiting dynamic reaction of phenyboronic acid moieties with polyvinyl alcohol (PVA) and ketone moieties with adipic dihydrazide (ADH) without any catalyst. The active boronate ester linkage endows the hydrogel with fast gelation kinetics and self-healing ability, and the stable acylhydrazone linkage can enhance the mechanical property of the hydrogel. The difference in kinetics endows that the contribution of each linkage to mechanical strength of the hydrogel can be accurately estimated. Moreover, the mechanical property of the hydrogel can be readily engineered by changing the composition and solid content, as well as by controlling the formation or dissociation of the dynamic linkages. Thus, we provide a promising strategy to design and prepare multi-responsive hydrogels with tunable properties.


2022 ◽  
Author(s):  
Qingyu Wang ◽  
Shuaibing Yu ◽  
Lianshun Zhang ◽  
Lei Wang ◽  
Jinming Kong ◽  
...  

An electrochemiluminescence approach based on surface-initiated reversible addition-fragmentation chain transfer (SI-RAFT) was developed for miRNA-21 detection for the first time. The SI-RAFT polymerization generates polymer chains with functional groups that...


2019 ◽  
Vol 10 (19) ◽  
pp. 2424-2435 ◽  
Author(s):  
Bingjie Zhao ◽  
Sen Xu ◽  
Sixun Zheng

A novel organic–inorganic ABA triblock copolymer with a poly(acrylate amide) (PAA) midblock and poly(POSS acrylate) [P(POSS)] endblocks was synthesized via sequential reversible addition–fragmentation chain transfer (RAFT) polymerization.


2011 ◽  
Vol 64 (12) ◽  
pp. 1602 ◽  
Author(s):  
Yingkai Liu ◽  
Mei Li ◽  
Dengxu Wang ◽  
Jinshui Yao ◽  
Jianxing Shen ◽  
...  

A series of well defined semitelechelic and mid-functionalized poly(poly(ethylene glycol) methyl ether methacrylate)s (poly(PEGMA)s) were synthesized through reversible addition-fragmentation chain transfer (RAFT) polymerization using thiazolidine-2-thione-functionalized chain transfer agents (CTAs). The thiazolidine-2-thione group was located either at the end or in the middle of polymer chains depending on the different structural CTAs. All polymers were fully analyzed by 1H NMR spectroscopy and GPC, confirming their well-defined structures, such as predesigned molecular weights, narrow polydispersity indices, and high yield chain-end or chain-middle functionalization. The thiazolidine-2-thione functionality located at the end of or at the middle of the polymer chains can react with amine residues on protein surfaces, forming protein-polymer conjugates via amide linkages. The bioactivity of protein conjugates were subsequently tested using micrococcus lysodeikticus cell as substitute. The protein conjugations from the mid-functionalized polymer remained much more protein bioactivity comparing to their semitelechelic counterpart with similar molecular weights, indicating the steric hindrance of the mid-functionalized poly(PEGMA)s lead to the better selective conjugation to protein. The number of polymer chains on the protein surface was additionally evaluated by TNBS analysis, exhibiting that there are less mid-functionalized poly(PEGMA)s linked on the protein surface than the semitelechelic polymers, also supporting the hypothesis that the steric hindrance from branch-structural polymers results in the better reaction selectivity. This synthetic methodology is suitable for universal proteins, seeking a balance between the protein bioactivity and the protein protection by the covalent linkage with polymer, and exhibits promising potential for pharmaceutical protein conjugation.


2013 ◽  
Vol 23 (36) ◽  
pp. 4390-4390 ◽  
Author(s):  
Hidenori Kuroki ◽  
Ihor Tokarev ◽  
Dmytro Nykypanchuk ◽  
Ekaterina Zhulina ◽  
Sergiy Minko

2019 ◽  
Vol 26 (37) ◽  
pp. 6797-6816 ◽  
Author(s):  
Ji Hyun Ryu ◽  
Gyeong Jin Lee ◽  
Yu-Ru V. Shih ◽  
Tae-il Kim ◽  
Shyni Varghese

Background: Phenylboronic acid-polymers (PBA-polymers) have attracted tremendous attention as potential stimuli-responsive materials with applications in drug-delivery depots, scaffolds for tissue engineering, HIV barriers, and biomolecule-detecting/sensing platforms. The unique aspect of PBA-polymers is their interactions with diols, which result in reversible, covalent bond formation. This very nature of reversible bonding between boronic acids and diols has been fundamental to their applications in the biomedical area. Methods: We have searched peer-reviewed articles including reviews from Scopus, PubMed, and Google Scholar with a focus on the 1) chemistry of PBA, 2) synthesis of PBA-polymers, and 3) their biomedical applications. Results: We have summarized approximately 179 papers in this review. Most of the applications described in this review are focused on the unique ability of PBA molecules to interact with diol molecules and the dynamic nature of the resulting boronate esters. The strong sensitivity of boronate ester groups towards the surrounding pH also makes these molecules stimuli-responsive. In addition, we also discuss how the re-arrangement of the dynamic boronate ester bonds renders PBA-based materials with other unique features such as self-healing and shear thinning. Conclusion: The presence of PBA in the polymer chain can render it with diverse functions/ relativities without changing their intrinsic properties. In this review, we discuss the development of PBA polymers with diverse functions and their biomedical applications with a specific focus on the dynamic nature of boronate ester groups.


e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Yu Liping ◽  
Zhu Jian ◽  
Cheng Zhenping ◽  
Zhang Zhengbiao ◽  
Zhang Wei ◽  
...  

Abstract An azobenzene-based dithiocarbamate, 4,4'-bis[2-(carbazole-N-dithio formatyl)-2-methyl-propionatyl]-azobenzene (CDMPA), was synthesized and used as the chain transfer agent (CTA) for reversible addition-fragmentation chain transfer (RAFT) polymerization of styrene in anisole solution. Well-defined azobenzene-centered and carbazole-ended polystyrene (PS) with well-controlled molecular weight (Mn) and narrow molecular weight distributions (Mw/Mn) was obtained. The good agreement between the theoretical molecular weight (Mn,th) and the 1H NMR determined molecular weight (Mn,NMR) indicated that most of the polymer chains contained an azo-functional center-group end-capped with the carbazole moieties, which were derived from the RAFT agent. The obtained polystyrene (PS) showed a strong ultraviolet absorption in tetrahydrofuran (THF) and emitted fluorescence after excited by UV-irradiation in N,N’-dimethyl formamide (DMF) solutions. The PS was used as the macro-RAFT agent to carry out the polymerization of methyl acrylate (MA) and N-isopropylacrylamide (NIPAAM). Triblock copolymers (PMA-b-PS-b-PMA), and pentablock copolymers (PNIPAAM-b-PMA-b-PS-b-PMA-b-PNIPAAM) were obtained, respectively. These copolymers were characterized by gel permeation chromatography (GPC), FT-IR spectroscopy and NMR spectroscopy.


Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 801
Author(s):  
Zhentao Hao ◽  
Weihua Li

The nepenthes-inspired lubricant-infused surface (LIS) is emerging as a novel repellent surface with self-healing, self-cleaning, pressure stability and ultra-slippery properties. Recently, stimuli-responsive materials to construct a smart LIS have broadened the application of LIS for droplet manipulation, showing great promise in microfluidics. This review mainly focuses on the recent developments towards the droplet manipulation on LIS with different mechanisms induced by various external stimuli, including thermo, light, electric, magnetism, and mechanical force. First, the droplet condition on LIS, determined by the properties of the droplet, the lubricant and substrate, is illustrated. Droplet manipulation via altering the droplet regime realized by different mechanisms, such as varying slipperiness, electrostatic force and wettability, is discussed. Moreover, some applications on droplet manipulation employed in various filed, including microreactors, microfluidics, etc., are also presented. Finally, a summary of this work and possible future research directions for the transport of droplets on smart LIS are outlined to promote the development of this field.


2020 ◽  
Vol 389 ◽  
pp. 123468 ◽  
Author(s):  
Jing Yan ◽  
Mengfei Li ◽  
Zhiwei Wang ◽  
Chen Chen ◽  
Chongqi Ma ◽  
...  

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