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Polymeric materials with antibacterial properties hold great promise for combating multidrug-resistant bacteria, which pose a significant threat to public health. However, the synthesis of most antibacterial polymers typically involves complicated and time-consuming procedures. In this study, we demonstrate a simple and efficient strategy for synthesizing functional poly(vinylpyridinium salt)s via pyridinium-yne click polymerization. This click polymerization could proceed with high atom economy under mild conditions without any external catalyst, yielding soluble and thermally stable poly(vinylpyridinium salt)s with satisfactory molecular weights and well-defined structures in excellent yields. Additionally, the incorporation of luminescent units such as fluorene, tetraphenylethylene, and triphenylamine into the polymer backbone confers excellent aggregation-enhanced emission properties upon the resulting polymers, rendering them suitable for bacterial staining. Moreover, the existence of pyridinium salt imparts intrinsic antibacterial activity against multidrug-resistant bacteria to the polymers, enabling them to effectively inhibit wound bacterial infection and significantly expedite the healing process. This work not only provides an efficient method to prepare antibacterial polymers, but also opens up the possibility of various applications of polymers in healthcare and other antibacterial fields.

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With the requirements for food safety and quality, there has been increasing attention on intelligent food packaging, especially pH-responsive intelligent packaging. However, the toxicity of indicators and the vulnerability of composite films to leakage tend to change the composition of food and endanger human health. In this study, 2-allyoxy-1-hydroxy-anthraquinone (AhAQ), a pH-responsive plant dye that was modified from alizarin (AI), was grafted onto the pH-responsive intelligent film (AhAQF) via click polymerization. The obtained AhAQF film shows color change in response to ammonia vapor and exhibits adequate reversibility after treatment with volatile acetic acid. The obtained AhAQF exhibits zero leakage, owing to the covalent immobilization of AhAQ. Thus, the prepared pH-responsive films are non-toxic and antibacterial and show promising application prospects in visual food intelligent packaging and gas-sensitive labels.

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Polyprodrug nanomedicines hold great potential for combating tumors. However, the functionalization of polyprodrug nanomedicines to improve therapeutic efficacy is restricted by conventional polymerization methods. Herein, we fabricated a charge-conversional click polyprodrug nanomedicine system by metal-free azide-alkyne cycloaddition click polymerization (AACCP) for targeted and synergistic cancer therapy. Specifically, Pt(IV) prodrug-backboned diazide monomer, DMC prodrug-pendent diazide monomer, dialkyne-terminated PEG monomer and azide-modified folate were click polymerized to obtain the target polyprodrug (P1). P1 could self-assemble into nano-micelles (1-NM), where PEG was the hydrophilic shell with folate on the surface, Pt(IV) and DMC prodrugs as the hydrophobic core. Taking advantage of PEGylation and folate-mediated tumor cell targeting, 1-NM achieved prolonged blood circulation time and high tumor accumulation efficiency. Tumor acidic microenvironment-responsive cleavage and cascade activation of pendant DMC prodrug induced surface charge conversion of 1-NM from negative to positive, which promoted tumor penetration and cellular internalization of the remaining 1-NM. After internalization into tumor cells, the reduction-responsive activation of Pt(IV) prodrug to Pt(II) further showed synergetic effect with DMC for enhanced apoptosis. This first designed charge-conversional click polyprodrug nanomedicine exhibited targeted and synergistic efficacy to suppress tumor proliferation in living mice bearing human ovarian tumor model.

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The development of chain-growth click polymerization is challenging yet desirable in modern polymer chemistry. In this work, we reported a novel chain-growth click polymerization based on the thiol-Michael reaction. This polymerization could be performed efficiently under ambient conditions and spatiotemporally regulated by ultraviolet light, allowing the synthesis of sulfur-containing polymers in excellent yields and high molecular weights. Density functional theory calculations indicated that the thiolate addition to the Michael acceptor is the rate-determining step, and introducing the phenyl group could facilitate the chain-growth process. This polymerization is a new type of chain-growth click polymerization, which will provide a unique approach to creating functional polymers.

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This study synthesized two azide-functionalized monomers through p-dichloro xylene and double-decker silsesquioxane (DDSQ) units with NaN3 to form DB-N3 and DDSQ-N3 monomers, respectively. In addition, five different propargyl-functionalized monomers were also prepared from hydroquinone, bisphenol A, bis(4-hydroxyphenyl)methanone, 2,4-dihydroxybenzaldehyde (then reacted with hydrazine hydrate solution) and 1,2-bis(4-hydroxyphenyl)-1,2-diphenylethene with propargyl bromide to form P-B, P-BPA, P-CO, P-NP, and P-TPE monomers, respectively. As a result, various DDSQ-based main chain copolymers could be synthesized using Cu(I)-catalyzed click polymerization through DDSQ-N3 with different propargyl-functionalized monomers, of which the chemical structure and molecular weight could be confirmed by using Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and gel permeation chromatography (GPC) analyses. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscope (SEM), transmission electron microscopy (TEM), and photoluminescence (PL) spectroscopy analyses also could characterize the thermal stability, morphology, and optical behaviors of these DDSQ-based copolymers. All results indicate that the incorporation of an inorganic DDSQ cage could improve the thermal stability such as thermal decomposition temperature and char yield, because of the DDSQ dispersion homogeneously in the copolymer matrix, and this would then affect the optical properties of NP and TPE units in this work.

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One of the most important threats to public health is the appearance of multidrug-resistant pathogenic bacteria, since they are the cause of a high number of deaths worldwide. Consequently, the preparation of new effective antibacterial agents that do not generate antimicrobial resistance is urgently required. We report on the synthesis of new linear cationic antibacterial polytriazoles that could be a potential source of new antibacterial compounds. These polymers were prepared by thermal- or copper-catalyzed click reactions of azide and alkyne functions. The antibacterial activity of these materials can be modulated by varying the size or nature of their side chains, as this alters the hydrophilic/hydrophobic balance. Antibacterial activity was tested against pathogens of the ESKAPE group. The P3TD polymer, which has butylated side chains, was found to have the highest bactericidal activity. The toxicity of selected polytriazoles was investigated using human red blood cells and a human gingival fibroblast cell line. The propensity of prepared polytriazoles to induce resistance in certain bacteria was studied. Some of them were found to not produce resistance in methicillin-resistant Staphylococcus aureus or Pseudomonas aeruginosa. The interaction of these polytriazoles with the Escherichia coli membrane produces both depolarization and disruption of the membrane.

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In this work, a porous capillary monolithic column was simply prepared by in situ thiol-alkyne click polymerization of dipentaerythritol hexakis (3-mercaptopropionate) and dimethyl dipropargylmalonate in fused-silica capillary. The capillary monolithic column shows excellent permeability, high porosity, and thoiether-rich groups, thereby, a high-efficient capacity for trace estrogens from complex samples are obtained via electron-donor-acceptor π-π interaction and hydrophobic interaction. The highest adsorption efficiency for estrogens is achieved at pH = 7.0 with a flow rate of 0.200 mL min-1. The superior adsorption capacities of the as-prepared capillary column for eight estrogens range from 0.092 mg m-1 to 0.31 mg m-1. A simple, reliable, and sensitive method for the determination of eight estrogens in biological and environmental samples is developed using the monolithic polymer as in-tube solid-phase microextraction coupled with ultrahigh performance liquid chromatography-tandem mass spectrometry (SPME-UPLC-MS/MS), and the total instrumental analysis time for the SPME-UPLC-MS/MS procedures was about 60 min per sample. The developed method shows a wide linear range (0.0500-5.00 µg L-1), and low limits of detection (5.34-9.63 ng L-1) for estrogens. The concentrations of estrogens in serum, urine, and pond water samples are found to be no more than 3.69, 0.741, and 1.04 µg L-1, respectively, and the satisfying recoveries for the eight estrogens range from 80.3% to 113% with relative standard deviations (n = 5) of 1.5-9.4%. The established method is highly potential for extraction and analysis of ultratrace target estrogens in complex matrices, such as biological and environmental samples.

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The hydrophobicity of polymer-based anion exchangers is a persistent problem in suppressed anionic chromatography (SAC) due to its adverse effect on chromatographic performance. Herein we describe polyelectrolyte-grafted anion exchangers with modified hydrophilic intermediate layers. The anion exchangers were functionalized by successively grafting a linear cationic condensation polymer (LCCP), a preprepared polyelectrolyte. The carboxylic/hydroxylic intermediate layers formed during thiol-radical-mediated polymerization exert distinct effects on the phase capacity and hydrophobicity. The separation of typical inorganic anions, polarizable anions, and organic acids shows that the anion exchangers display good performance in SAC mode.

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Exosomes, as a biomarker with enhancing tumor invasion and spread, play an essential role for lung cancer diagnosis, therapy, and prognosis. In this work, a novel electrochemical sensor was fabricated for detecting exosomes secreted by lung cancer cells based on polysaccharide-initiated ring-opening polymerization (ROP) and click polymerization. First, MPA formed a self-assembled monolayer on the gold electrode surface, and then anti-EGFR was immobilized on the electrode surface by amide bond. Subsequently, a lot of phosphate groups were introduced by the specific recognition between anti-EGFR and exosomes, then sodium alginate grafted Glycidyl propargyl ether (SA-g-GPE) prepared via ROP was attached to the exosomes through PO43-Zr4+-COOH coordination bond. After that, click polymerization was initiated by alkyne groups on the SA-g-GPE polymerization chain to realize highly sensitive detection of A549 exosomes. Under the optimum conditions, the fabricated sensor showed a good linear relationship between the logarithm of exosomes concentration and peak current in the range of 5 × 103 - 5 × 109 particles/mL, and the limit of detection (LOD) was as low as 1.49 × 102 particles/mL. In addition, this method had the advantages of high specificity, anti-interference, high sensitivity, simplicity, rapidity and green economy, which proposed a novel avenue for the detection of exosomes, and also had potential applications in early cancer diagnosis and biomedicine.

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Novel linear cationic poly(amide aminotriazole)s (PATnD) with secondary amine groups in the backbone were obtained by using azide-alkyne 1,3-dipolar cycloaddition reactions: metal- and solvent-free (thermal conditions, PATTnD) or copper(I)-catalyzed (Sharpless conditions, PATCnD). PATnD were investigated in vitro against strains of E. coli, P. aeruginosa, S. aureus, and S. epidermidis. Hemolytic activity was tested using human red blood cells (hRBC), and very low or no hemolytic activity was observed. The cytotoxicity of PATnD polymers against Human Gingival Fibroblasts (HGnF) cells was concentration-dependent, and significant differences between PATT1D and PATC1D were observed. The ability of these polymers to induce resistance against both Gram-positive and Gram-negative bacteria was also assessed. Studied bacterial strains acquired resistance to catalytic polymers (PATCnD) in initial passages meanwhile resistance to thermal polymers (PATTnD) appears in later passages, being the increase of the minimum inhibitory concentration lower than in catalytic polymers. This result, together with the higher biocidal capacity of thermal polymers compared to catalytic ones, seems to suggest an influence of the regiospecificity of the polymers on their antibacterial characteristics. This study also demonstrates that PAT1D polymers, which do not appear to have strong hydrophobic residues, can exert significant antimicrobial activity against Gram-positive bacteria such as S. epidermidis. This pair of polymers, PATC1D and PATT1D, displays the greatest antimicrobial activity while not causing significant hemolysis along with the lowest susceptibility for resistance development of the polymers evaluated.

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It is challenging to synthesize stimuli-responsive materials with the well-balanced performance of fast stimulus-response speed, good mechanical strength, multi-functionality, and deformation diversity as well. This work reports a facile, one-step thiol-ene click polymerization strategy for preparation of water/acetone vapor-responsive hierarchical films, by using diallyl terephthalate (P) as hydrophobic ene-monomer, 1,4-diallyl-1,4-diazabicyclo [2.2.2]octane-1,4-diium bromide (B) as hydrophilic ene-monomer, and pentaerythritol tetra(3-mercaptopropionate) (PETMP) as thiol monomer. Besides, by taking advantage of the specific hydrophilic/hydrophobic induction effect of substrate and adjusting the molar ratio of P to B, P60 B40 -HPI film is fabricated on hydrophilic substrate "with plasma treatment" whereas P80 B20 -HPO film is obtained on hydrophobic substrate "without plasma treatment". Their "upper-dense and lower-porous" structural feature ensured the excellent combination of fast stimuli-response speed endowed by the porous structure and good mechanical strength enhanced by the upper dense surface. Both films are bidirectional water/acetone vapor-responsive materials, but their bending directions responding to the stimuli factors are completely opposite. This strategy showed great potential in the development of smart stimuli-responsive materials.

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Three azido-terminated poly(ethylene glycol) macromonomers (ATPEGs) were synthesized from poly(ethylene glycol)s (PEGs) and characterized. The extended polytriazole (EPTA) resins were prepared from the macromonomers, azide and alkyne monomers. Toughening effect of PEGs on polytriazole resins was analyzed by means of mechanical, thermal and electronic microscope characterization. The results show that molecular weight and content of ATPEGs have great influence on the thermal and mechanical properties of cured EPTA resins. The impact strength of cured EPTA resins increases with the increase of the amount and molecular weight of ATPEGs. The flexural strength and heat resistance of cured EPTA resins decrease with the increase of addition amount and molecular weight of ATPEGs. High impact EPTA resins were obtained.

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The vast application potentials of bacterial cellulose (BC)-based materials for developing leather-like materials, wound-healing materials and electronic materials have been realized very recently. Surface functionalization of these materials can help in improvement of certain properties such as water repellency, mechanical strength, and so forth. In this paper, we reported functionalization of BC surfaces using "click" polymerization for the first time. By this methodology, dense aromatic groups have been incorporated for the improvement of hydrophobicity. For comparative studies, various fluorine-based compounds have been introduced using conventional click reactions. The surface-modified BC materials have been confirmed by various spectroscopic methods. Particularly, the chemical structures of the materials were studied by solid-state 13C NMR spectroscopy and attenuated total reflection-infrared spectroscopy. X-ray photoelectron spectroscopy was used to study the elemental composition of the materials. Moreover, the crystallite changes of modified BC surfaces were investigated by X-ray diffraction. Further, the changes in the morphology of the material after functionalization were evaluated by scanning electron microscopy and atomic force microscopy. Finally, water contact angle measurement revealed manyfold increase in hydrophobicity after click polymerization. A video is also provided in the Supporting Information to show the application potential of this material for developing leather-like materials.

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A new synthesis of amphiphilic homopolymers is described. In this synthesis, commercially available and inexpensive primary amines and di-epoxide molecules are utilized as AA- and BB-types of monomers in an amine-epoxy 'click' polymerization process. This process can be carried out in water and at room temperature. It does not require a catalyst or inert conditions and forms no byproducts. Therefore, the polymer synthesis can be carried out in open-air and bench-top conditions and a post-synthesis purification step is not required. The modularity of the synthesis, on the other hand, allows for facile structural modulation and tuning of the thermally triggered aggregation process in the temperature range of 7 to 91 °C. Finally, the underlying principles can be translated from linear architectures to polymer networks (hydrogels).

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The core-shell structure molecularly imprinted magnetic nanospheres towards hypericin (Fe3O4@MIPs) were prepared by mercapto-alkyne click polymerization. The shape and size of nanospheres were characterized by dynamic light scattering (DLS) and transmission electron microscope (TEM). The nanospheres were analyzed by FTIR spectroscopy to verify the thiol-yne click reaction in the presence or absence of hypericin. The Brunauer⁻Emmet⁻Teller (BET) method was used for measuring the average pore size, pore volume and surface area. The Fe3O4@MIPs synthesized displayed a good adsorption capacity (Q = 6.80 µmol·g-1). In addition, so-prepared Fe3O4@MIPs showed fast mass transfer rates and good reusability. The method established for fabrication of Fe3O4@MIPs showed excellent reproducibility and has broad potential for the fabrication of other core-shell molecularly imprinted polymers (MIPs).

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Polymer self-assembly has been a hot research topic for several decades. Different types of polymers with various architectures, like block copolymers, brush polymers, hyperbranched polymers and dendrimers, etc., are currently being investigated. Alternating copolymers (ACPs) are regular copolymers with an alternating monomeric unit structure in the polymer backbones. However, despite the great progress in the synthesis of ACPs, their self-assembly is still in an infant stage. Very recently, our group reported a new type of amphiphilic ACPs through click copolymerization and obtained spheres, vesicles, nanotubes, and even hierarchical sea urchin-like aggregates through the self-assembly process. In addition, we have found some intriguing features in the self-assembly of amphiphilic ACPs when compared with other copolymers, including their facile syntheses, readily functionalization, novel self-assembly structures, new folding-chain mechanisms, and uniform but ultrathin feature length. In this Concept article, we present the self-assembly of amphiphilic ACPs together with their unique features by reviewing our latest results and related studies. Moreover, the future perspective on the self-assembly of amphiphilic ACPs is also proposed. Our aim is to capture the attention and interest of chemists in this new area of polymerization.

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Click polymerization, a powerful synthetic technique to construct polymers with unique structures and advanced functions, is of crucial importance in the areas of polymer and material sciences. A variety of click polymerizations such as azide-alkyne, thiol-yne, amino-yne, and hydroxyl-yne reactions have been established, wherein the catalytic systems play an indispensable role in realizing these highly practical reactions based on triple-bond building blocks, as they directly influence the efficiencies of the click polymerizations and the performances of the resultant polymers. The vital employment of catalysts is reviewed and their developments from innovative discoveries to the eminent position are outlined. Moreover, the challenges and perspectives in this area are also briefly discussed.

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Polymers with aggregation-induced emission (AIE) characteristics have aroused tremendous interest because of their potential applications in large-area flexible display and luminescent self-assembling, and as stimuli-responsive and porous materials. However, the design of AIE-active polymers is always not as easy as that of small molecules because their properties are hard to predict. In some cases, the polymers prepared from the AIE-active monomers show the aggregation-caused quenching (ACQ) instead of AIE effect. To understand the structure-property relationship of the polymers constructed from the AIE monomers, in this paper, two pyrazine-containing AIE monomers were utilized to construct luminescent polymers by click polymerization. The photophysical property investigation indicates that the polytriazole containing tetraphenylpyrazine units is AIE-active, whereas that bearing 2,3-dicyano-5,6-diphenylpyrazine units suffers from the ACQ effect. Through systematical investigation, the cause for such difference was unveiled. Thus, this work provides a useful guidance for further design of AIE-active polymers.

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Developing efficient unimolecular visible light-emitting diode (LED) light photoinitiators (PIs) with photobleaching capability, which are essential for various biomedical applications and photopolymerization of thick materials, remains a great challenge. Herein, we demonstrate the synthesis of a series of novel PIs, containing coumarin moieties as chromophores and oxime ester groups as initiation functionalities and explore their structure-activity relationship. The investigated oxime esters can effectively induce acrylates and thiol-based click photopolymerization under 450 nm visible LED light irradiation. The initiator O-3 exhibited excellent photobleaching capability and enabled photopolymerization of thick materials (∼4.8 mm). The efficient unimolecular photobleachable initiators show great potential in dental materials and 3D printings.

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Ferrocene-based polymers have drawn much attention in the past decades due to their unique properties and promising applications. However, the synthesis of hyperbranched polymers is still a great challenge. Here, two ferrocene-based hyperbranched polytriazoles with high molecular weights are facilely prepared by the click polymerization reactions of ferrocene-containing diazides (1) and tris(4-ethynylphenyl)amine (2) using Cu(PPh3 )3 Br as catalyst in dimethylformamide at 60 °C for 5 and 9 h in satisfactory yields of 54.0% and 52.3%. The resulting polytriazoles are soluble in common organic solvents and thermally stable, with 5% weight loss temperatures up to 307 °C. They can be used as precursors to produce nanostructured ceramics with good magnetizability by pyrolysis at elevated temperature.

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