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π-Conjugated-polymer-based nanofibers (CPNFs) of controlled length, composition and morphology are promising for a broad range of emerging applications in optoelectronics, biomedicine and catalysis, owing to the morphological merits of fiber-like nanostructures and structural attributes of π-conjugated polymers. Living crystallization-driven self-assembly (CDSA) of π-conjugated-polymer-containing block copolymers (BCPs) has emerged as an efficient strategy to prepare CPNFs with precise dimensional and structural controllability by taking advantage of the crystallinity of π-conjugated polymers. In this review, recent advances in the generation of CPNFs have been highlighted. The influence of the structure of π-conjugated-polymer-containing BCPs and experimental conditions on the CDSA behaviors, especially seeded growth and self-seeding processes of living CDSA, has been discussed in detail, aiming to provide an in-depth overview of living CDSA of π-conjugated-polymer-containing BCPs. In addition, the properties of CPNFs as well as their potential applications have been illustrated. Finally, we put forward the current challenges and research directions in the field of CPNFs. [ABSTRACT FROM AUTHOR]

Background. Sevoflurane is commonly used as a general anesthetic in neonates to aged patients. Preconditioning or postconditioning with sevoflurane protects neurons from excitotoxic injury. Conversely, sevoflurane exposure induces neurotoxicity during early or late life. However, little is known about the underlying mechanism of the dual effect of sevoflurane on neurons. Autophagy is believed to control neuronal homeostasis. We hypothesized that autophagy determined the dual effect of sevoflurane on neurons. Methods. DTome was used to identify the direct protein target (DPT) of sevoflurane. The STRING database was employed to investigate the proteins associated with the DPTs. Protein-protein interaction was assessed using Cytoscape. WebGestalt was used to analyze gene set enrichment. The linkage between candidate genes and autophagy was identified using GeneCards. Results. This study found that 23 essential DPTs of sevoflurane interacted with 77 proteins from the STRING database. GABARAPL1 and 2, both of which are DPT- and autophagy-associated proteins, were significantly expressed in the brain and enriched in GABAergic synapses. Conclusions. Taken together, our findings showed that the network of sevoflurane-DPT-GABARAPL1 and 2 is related to the dual effect of sevoflurane on neurons. [ABSTRACT FROM AUTHOR]

Background: Intravenous remifentanil patient-controlled analgesia (RPCA) is an alternative for epidural analgesia (EA) in labor pain relief. However, it remains unknown whether RPCA is superior to EA in decreasing the risk of intrapartum maternal fever during labor.Methods: According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic review and meta-analysis was performed by searching PubMed, EMBASE and the Cochrane Central Register of Controlled Trials from inception to April 2019. All randomized controlled trials (RCTs) investigating the risk of intrapartum maternal fever with RPCA compared with EA alone or EA in combination with spinal analgesia during labor were included.Results: A total of 825 studies were screened, and 6 RCTs including 3341 patients were identified. Compared with EA, RPCA was associated with a significantly lower incidence of intrapartum maternal fever (risk ratio [RR] 0.48, P = 0.02, I2 = 49%) during labor analgesia. After excluding 2 trials via the heterogeneity analysis, there was no difference in the incidence of intrapartum fever between patients receiving RPCA and those receiving EA. Satisfaction with pain relief during labor was lower in the RPCA group than that in the EA group (- 10.6 [13.87, - 7.44], P < 0.00001, I2 = 0%). The incidence of respiratory depression was significantly greater in the RPCA group than that in the EA group (risk ratio 2.86 [1.65, 4.96], P = 0.0002, I2 = 58%). The incidence of Apgar scores < 7 at 5 min in the RPCA group was equivalent to that in the EA group.Conclusion: There is no solid evidence to illustrate that the incidence of intrapartum maternal fever is lower in patients receiving intravenous RPCA than in patients receiving EA. [ABSTRACT FROM AUTHOR]

ABSTRACT A novel ABA triblock copolymer comprising double-bond-containing poly(phenoxyallene) (PPOA) and polystyrene (PS) segments was synthesized by sequential conventional free radical polymerization and atom transfer radical polymerization (ATRP) via the site transformation strategy. A new bifunctional initiator containing azo and Br-containing ATRP initiating groups was prepared using 2-bromopropionyl chloride, hydroquinone, and 4,4′-azobis(4-cyanopentanoic acid) as starting materials. Conventional free radical homopolymerization of phenoxyallene with cumulated double bond was performed in toluene to provide a polyallene-based macroinitiator bearing ATRP initiating groups at both ends, which is stable under UV irradiation and free radical circumstances. PS- b-PPOA- b-PS triblock copolymer was then obtained by bulk ATRP of styrene initiated by PPOA-based macroinitiator. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 1366-1372 [ABSTRACT FROM AUTHOR]

Three new acrylamide monomers containingferrocene and tert-butyl ester groups were firstsynthesized via multistepnucleophilic substitution reaction under mild conditions followedby reversible addition–fragmentation chain transfer (RAFT)homopolymerization to give well-defined homopolymers with narrow molecularweight distributions (Mw/Mn≤ 1.36). The target amphiphilic homopolymerswere obtained by the acidic hydrolysis of tert-butyoxycarbonylsto carboxyls in every repeating unit using CF3COOH. Theself-assembly behaviors of these amphiphilic homopolymers bearingboth ferrocene and carboxyl moieties in each repeating unit in aqueousmedia were investigated by transmission emission microscopy (TEM),dynamic light scattering (DLS), and atomic force microscopy (AFM).Large compound micelles with different morphologies were formed bythese amphiphilic homopolymers, which consist of the corona formedby hydrophilic carboxyls and the core containing numerous reversemicelles with hydrophilic islandsof carboxyls in continuous hydrophobic phase of ferrocene-based segments.The morphologies of the formed micelles could be tuned by the concentrationof amphiphilic homopolymers, pH value of the solution, the lengthof −CH2linker between ferrocene group and carboxyl,and the amount of β-cyclodextrin (β-CD). [ABSTRACT FROM AUTHOR]

A series of polyallene-based well-defined amphiphilic graft copolymers, poly(6-methyl-1,2-heptadiene-4-ol)- g-poly(2-(diethylamino)ethyl methacrylate) (PMHDO- g-PDEAEMA), was synthesized through the grafting-from technique. First, double-bond-containing PMHDO backbone bearing pendant hydroxyls was prepared via [(η3-allyl)NiOCOCF3]2-initiated living coordination polymerization of 6-methyl-1,2-heptadiene-4-ol (MHDO). The pendant hydroxyls in the homopolymer were then reacted with 2-chloropropionyl chloride to give PMHDO-Cl macroinitiator. Finally, hydrophilic PDEAEMA side chains were formed by single electron transfer-living radical polymerization (SET-LRP) of 2-(diethylamino)ethyl methacrylate (DEAEMA) in THF/H2O initiated by the macroinitiator using CuCl/Me6TREN as catalytic system to afford PMHDO- g-PDEAEMA graft copolymers. The narrow molecular weight distributions ( Mw/ Mn ≤ 1.35) and kinetics experiment showed the controllability of SET-LRP graft copolymerization of DEAEMA. The critical micelle concentration (cmc) of PMHDO- g-PDEAEMA amphiphilic graft copolymer in aqueous media was determined by fluorescence probe technique and the relationships between cmc and pH or salinity were also investigated. Micellar morphologies were preliminarily explored using transmission electron microscopy. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 [ABSTRACT FROM AUTHOR]

A well-defined amphiphilic graft copolymer, poly(6-methyl-1,2-heptadien-4-ol)- g-poly(2-(dimethylamino)ethyl methacrylate) (PMHDO- g-PDMAEMA), has been synthesized by the combination of living coordination polymerization, single electron transfer-living radical polymerization (SET-LRP), and the grafting-from strategy. PMHDO backbone containing double bonds and pendant hydroxyls was first prepared by [(η3-allyl)NiOCOCF3]2-initiated living coordination polymerization of 6-methyl-1,2-heptadien-4-ol (MHDO) followed by treating the pendant hydroxyls with 2-chloropropionyl chloride to give PMHDO-Cl macroinitiator. SET-LRP of 2-(dimethylamino)ethyl methacrylate (DMAEMA) was performed in THF/H2O using PMHDO-Cl as macroinitiator and CuCl/Me6TREN as catalytic system to afford the well-defined PMHDO- g-PDMAEMA graft copolymer with a narrow molecular weight distribution ( Mw/ Mn = 1.28). The grafting density was as high as 92%. The critical micelle concentration (cmc) in water was determined by fluorescence probe technique and the micellar morphology was preliminarily explored by transmission electron microscopy. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 [ABSTRACT FROM AUTHOR]

A series of well-defined amphiphilic graft copolymer containing hydrophobic polyallene-based backbone and hydrophilic poly(2-(diethylamino)ethyl acrylate) (PDEAEA) side chains was synthesized by sequential living coordination polymerization of 6-methyl-1,2-heptadiene-4-ol (MHDO) and single electron transfer-living radical polymerization (SET-LRP) of 2-(diethylamino)ethyl acrylate (DEAEA). Ni-catalyzed living coordination polymerization of MHDO was first performed in toluene to give a well-defined double-bond-containing poly(6-methyl-1,2-heptadiene-4-ol) (PMHDO) homopolymer with a low polydispersity ( Mw/ Mn = 1.10). Next, 2-chloropropionyl chloride was used for the esterification of pendant hydroxyls in every repeating unit of the homopolymer so that the homopolymer was converted to PMHDO-Cl macroinitiator. Finally, SET-LRP of DEAEA was initiated by the macroinitiator in tetrahydrofuran/H2O using CuCl/tris(2-(dimethylamino)ethyl)amine as catalytic system to afford well-defined PMHDO- g-PDEAEA graft copolymers ( Mw/ Mn ≤ 1.22) through the grafting-from strategy. The critical micelle concentration ( cmc) was determined by fluorescence spectroscopy with N-phenyl-1-naphthylamine as probe and the micellar morphology was visualized by transmission electron microscopy. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 [ABSTRACT FROM AUTHOR]

A well-defined amphiphilic graft copolymer, consisting of hydrophobic polyallene-based backbone and hydrophilic poly( N-isopropylacrylamide) (PNIPAM) side chains, was prepared by the combination of living coordination polymerization, single electron transfer-living radical polymerization (SET-LRP), and the grafting-from strategy. First, the double-bond-containing backbone was prepared by [(η3-allyl)NiOCOCF3]2-initiated living coordination polymerization of 6-methyl-1,2-heptadiene-4-ol (MHDO). Next, the pendant hydroxyls in every repeating unit of poly(6-methyl-1,2-heptadiene-4-ol) (PMHDO) homopolymer were treated with 2-chloropropionyl chloride to give PMHDO-Cl macroinitiator. Finally, PNIPAM side chains were grown from PMHDO backbone via SET-LRP of N-isopropylacrylamide initiated by PMHDO-Cl macroinitiator in N,N-dimethylformamide/2-propanol using copper(I) chloride/tris(2-(dimethylamino)ethyl)amine as catalytic system to afford PMHDO- g-PNIPAM graft copolymers with a narrow molecular weight distribution ( Mw/ Mn = 1.19). The critical micelle concentration ( cmc) in water was determined by fluorescence probe technique and the effects of pH and salinity on the cmc of PMHDO- g-PNIPAM were also investigated. The micellar morphology was found to be spheres using transmission electron microscopy. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 [ABSTRACT FROM AUTHOR]

• LncRNA WNT5A-AS was upregulated in NSC exposed to sevoflurane. • LncRNA WNT5A-AS KD restored the proliferation of NSC exposed to sevoflurane. • LncRNA WNT5A-AS KD inhibited WNT5A/Ryk-ROS expression. Long noncoding RNAs (lncRNAs) have been implicated in neurogenesis. LncRNA WNT5A-AS is upregulated in neural stem cells (NSCs), the proliferation of which is inhibited by sevoflurane. Thus, we hypothesized that knocking down of lncRNA WNT5A-AS may restore the fate of NSCs exposed to sevoflurane. To test this hypothesis, NSCs obtained from postnatal Sprague-Dawley rats were exposed to 2.4% sevoflurane or control gas for 6 h. Bioinformatics analysis, quantitative PCR and RNA interference technology were used to identify the properties of lncRNA WNT5A-AS. Cell proliferation was assessed using counting a Cell Counting Kit-cell 8 assay, a 5-ethynyl-2′-deoxyuridine incorporation assay, and a plate cloning assay. Cell survival was detected by flow cytometry, which was also used to examine the levels of reactive oxygen species (ROS) and the cell cycle. The levels of WNT5A and receptor tyrosine kinase (Ryk) were measured via Western blotting. LncRNA WNT5A-AS was identified to have low coding potency and to be located on the antisense strand of WNT5A. The level of upregulated lncRNA WNT5A-AS was positively correlated with that of WNT5A in response to sevoflurane exposure. The knockdown of lncRNA WNT5A-AS promoted the proliferation and survival of NSCs, whereas it suppressed the WNT5A/Ryk-ROS signaling and drove cell cycle processes. Taken together, findings strongly suggest that the inhibition of lncRNA WNT5A-AS can rescue the fate of NSCs. In addition, WNT5A/Ryk-ROS signaling might be a downstream target of lncRNA WNT5A-AS. [ABSTRACT FROM AUTHOR]

Background: Propofol, a widely used sedative in endoscopic procedures, sometimes causes cardiopulmonary complications. Intravenous lidocaine can diminish visceral pain and decrease the dose of propofol. The purpose of this study was to assess the efficacy and safety of intravenous lidocaine in reducing propofol dosage during paediatric colonoscopy. Methods: Forty children who underwent colonoscopy were divided into two groups. Lidocaine hydrochloride (1.5 mg/kg induction and 2 mg/kg/h maintenance) was given intravenously to the lidocaine group, and the same amount of saline was given to the control group after they received lidocaine induction. Propofol initial plasma concentration of 5 μg/mL was targeted, and the procedure was performed after the bispectral index value reached 55. The primary outcome was propofol requirement. Results: The propofol requirement in the lidocaine group was decreased by 35.5% (128.6 ± 30.4 mg vs. 199.4 ± 57.6 mg; p < 0.001; 95%CI: − 100.60, − 41.02). The incidence of involuntary body movements was significantly lower in the lidocaine group (p = 0.028; OR = 0.17; 95%CI: 0.03, 0.92). The awakening time (p < 0.001; 95%CI: − 7.67, − 5.13) and recovery times (p < 0.001; 95%CI: − 7.45, − 4.35) were significantly lower in the lidocaine group. Pain was significantly less at 30 min and 60 min after the procedure in the lidocaine group (0 [0–4] vs. 3 [0–5], p < 0. 001; 0 [0–2] vs. 1 [0–3], p = 0.001). There was no difference in the incidence of bradycardia, hypotension, or hypoxia between the two groups. Conclusions: For colonoscopy procedures in paediatric patients, intravenous lidocaine reduces the amount of propofol needed, provides better sedation and postprocedural pain management, as well as a reduction in recovery time. Trial registration: The trial was registered on November 6, 2020 at China Clinical Trials Registration Center (www.chictr.org.cn) ref.: ChiCTR 2,000,039,706. [ABSTRACT FROM AUTHOR]

An efficient strategy for growing thermo-sensitive polymers from the surface of exfoliated graphene oxide (GO) is reported in this article. GO sheets with hydroxyls and epoxy groups on the surface were first prepared by modified Hummer's method. Epoxy groups on GO sheets can be easily modified through ring-opening reactions, involving nucleophilic attack by tris(hydroxymethyl) aminomethane (TRIS). The resulting GO-TRIS sheets became a more versatile precursor for next ring opening polymerization (ROP) of ethyl ethylene phosphate (EEP), leading to GO-TRIS/poly(ethyl ethylene phosphate) (GO-TRIS-PEEP) nanocomposite. The nanocomposite was characterized by 1H NMR, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), differential thermal gravity (DTG), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Since hydrophilic PEEP chains make the composite separate into single layers through hydrogen bonding interaction, the dispersity of the functionalized GO sheets in water is significantly improved. Meanwhile, the aqueous dispersion of GO-TRIS-PEEP nanocomposite shows reversible temperature switching self-assembly and disassembly behavior. Such a smart graphene oxide-based hybrid material is promising for applications in the biomedical field. [ABSTRACT FROM AUTHOR]

Living crystallization‐driven self‐assembly (CDSA) has emerged as an efficient route to generate π‐conjugated‐polymer‐based nanofibers (CPNFs) with promising applications from photocatalysis to biomedicine. However, the lack of efficient tools to endow CPNFs with morphological stability and surface tailorability becomes a frustrating hindrance for expanding application spectrum of CPNFs. Herein, a facile strategy to fabricate length‐controllable OPV‐based (OPV = oligo(p‐phenylenevinylene)) CPNFs containing a cross‐linked shell with high morphological stability and facile surface tailorability through the combination of living CDSA and thiol–ene chemistry by using OPV5‐b‐PNAAM32 (PNAAM = poly(N‐allyl acrylamide)) as a model is reported. Uniform fiber‐like micelles with tunable length can be generated by self‐seeding of living CDSA. By taking advantage of radical thiol–ene reaction between vinyls of PNAAM corona and four‐arm thiols, the shell of micelles can be cross‐linked with negligible destruction of structure of vinylene‐containing OPV core. The resulting micelles show high morphological stability in NaCl solution and PBS buffer, even upon heating at 80 °C. The introduced extra thiol groups in the cross‐linked shell can be further employed to install extra functional moieties via convenient thiol‐Michael‐type reaction. Given the negligible cytotoxicity of resulting CPNFs, this strategy opens an avenue to fabricate various CPNFs of diverse functionalities for biomedicine. [ABSTRACT FROM AUTHOR]

A series of ABA triblock copolymers, consisting of double-bond-containing poly(phenoxyallene) (PPOA), poly(methyl methacrylate) (PMMA), or poly(butyl acrylate) (PBA) segments, were synthesized by sequential free radical polymerization and atom transfer radical polymerization (ATRP). A new bifunctional initiator bearing azo and halogen-containing ATRP initiating groups was first prepared followed by initiating conventional free radical homopolymerization of phenoxyallene with cumulated double bond to give a PPOA-based macroinitiator with ATRP initiating groups at both ends. Next, PMMA-b-PPOA-b-PMMA and PBA-b-PPOA-b-PBA triblock copolymers were synthesized by ATRP of methyl methacrylate and n-butyl acrylate initiated by the PPOA-based macroinitiator through the site transformation strategy. These double-bond-containing triblock copolymers are stable under UV irradiation and free radical circumstances. [ABSTRACT FROM AUTHOR]

Background: To evaluate the safety and effectiveness of different dosages of intranasal Dexmedetomidine (DEX) in combination with oral midazolam for sedation of young children during brain MRI examination. Methods: Included in this prospective single-blind randomized controlled trial were 156 children aged from 3 months to 6 years and weighing from 4 to 20 Kg with ASA I-II who underwent brain MRI examination between March 2021 and February 2022. Using the random number table method, they were divided into group A (using 3 ug/kg intranasal DEX plus 0.2 mg/Kg oral midazolam) and group B (using 2 ug/kg intranasal DEX plus 0.2 mg/Kg oral Midazolam). The one-time success rate of sedation, sedation onset time, recovery time, overall sedation time, and occurrence of adverse reactions during MRI examination were compared between the two groups. The heart rate (HR), mean arterial pressure (MAP), and percutaneous SpO2before and after drug administration were observed in both groups. Differences in sedation scores between the two groups were compared before intranasal drug administration (T0), 10 min after drug administration (T1), at the time of falling asleep (T2), at the end of examination (T3), and at the time of recovery (T4). Results: The one-time success rate of sedation in group A and B was 88.31% and 79.75% respectively, showing no significant difference between the two groups (P>0.05). The sedation onset time in group A was 24.97±16.94 min versus 27.92±15.83 min in group B, and the recovery time was 61.88±22.18 min versus 61.16±28.16 min, both showing no significance difference between the two groups (P>0.05). Children in both groups exhibited good drug tolerance without presenting nausea and vomiting, hypoxia, or bradycardia and hypotension that needed clinical interventions. There was no significant difference in the occurrence of abnormal HR, MAP or other adverse reactions between the two groups (P>0.05). Conclusion: 3 ug/kg or 2 ug/kg intranasal DEX in combination with 0.2 mg/kg oral Midazolam both are safe and effective for sedation of children undergoing MRI examination with the advantages of fast-acting and easy application. Trial registration: It was registered at the Chinese Clinical Trial Registry (ChiCTR1800015038) on 02/03/2018. [ABSTRACT FROM AUTHOR]

A homopolymer strategy was developed to synthesize temperature and pH/CO 2 stimulus-responsive homopolymers. A new class of acrylamide monomers bearing oligo(ethylene glycol) unit and N,N -diethylaminoethyl group were designed and prepared through Aza-Michael addition reaction followed by amidation with acryloyl chloride using amino group as a linkage to connect oligo(ethylene glycol), N,N -diethylaminoethyl, and polymerizable double bond groups together. Subsequently, the corresponding homopolymers containing oligo(ethylene glycol) unit and N,N -diethylaminoethyl group in each repeated unit were prepared via RAFT polymerization with controlled molecular weights and relatively narrow molecular weight distributions. The lower critical solution temperature (LCST) of homopolymer was examined to be influenced by molecular weight, salt concentration, and pH value of aqueous solution. The LCSTs of homopolymers could be tuned in a wide temperature window by changing pH value of aqueous solution and it increased with the decrease of pH value. Particularly, CO 2 gas as a unique pH stimulus can also reversibly adjust the solubility of homopolymer without the addition of acids or bases. [ABSTRACT FROM AUTHOR]

A well-defined amphiphilic graft copolymer, consisting of hydrophobic poly( tert-butyl acrylate) (P tBA) backbone and hydrophilic poly( N-vinylcaprolactam) (PNVCL) side chains, was synthesized by successive reversible addition-fragmentation chain transfer (RAFT) polymerization and atom transfer radical polymerization (ATRP). A new acrylate monomer bearing a chlorine-based initiating group, tert-butyl 2-((2-chloropropanoyloxy)methyl)acrylate, was first RAFT homopolymerized in a controlled way to give a well-defined homopolymer with a narrow molecular weight distribution ( Mw/ Mn=1.15). This homopolymer directly initiated ATRP of N-vinylcaprolactam (NVCL) to afford a well-defined P tBA- g-PNVCL graft copolymer ( Mw/ Mn=1.22) via the grafting-from strategy without polymeric functionality transformation. PAA- g-PNVCL graft copolymer was prepared by selectively hydrolyzing P tBA- g-PNVCL. Ornidazole (ONZ)-loaded polymeric micelles using PAA- g-PNVCL copolymer as carrier were prepared by physical entrapping. Drug release experiment of the nano-carrier indicated the pH-dependent drug release characteristics. [ABSTRACT FROM AUTHOR]

ABSTRACT A series of well-defined amphiphilic diblock copolymers consisting of hydrophobic polyisobutylene (PIB) and hydrophilic poly(2-(diethylamino)ethyl methacrylate) (PDEAEMA) segments was synthesized via the combination of living carbocationic polymerization and reversible addition fragmentation chain transfer (RAFT) polymerization. Living carbocationic polymerization of isobutylene followed by end-capping with 1,3-butadiene was first performed at −70 °C to give a well-defined allyl-Cl-terminated PIB with a low polydispersity ( Mw/ Mn =1.29). This end-functionalized PIB was further converted to a macromolecular chain transfer agent for mediating RAFT block copolymerization of 2-(diethylamino)ethyl methacrylate at 60 °C in tetrahydrofuran to afford the target well-defined PIB- b-PDEAEMA diblock copolymers with narrow molecular weight distributions ( Mw/ Mn ≤1.22). The self-assembly behavior of these amphiphilic diblock copolymers in aqueous media was investigated by fluorescence spectroscopy and transmission electron microscope, and furthermore, their pH-responsive behavior was studied by UV-vis and dynamic light scattering. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1478-1486 [ABSTRACT FROM AUTHOR]

Co‐self‐seeding has emerged as a versatile approach toward obtaining uniform fiber‐like comicelles with controlled length and morphology. The critic dissolution temperature (Tc) of seed micelles is one of the most important factors dictating the length and morphology of resulting comicelles. To vary the length and morphology of comicelles generated via co‐self‐seeding approach, one usually needs to use a new block copolymer (BCP) with different core‐forming and/or corona‐forming segment, which requires tedious synthesis. Herein, a postmodification strategy is reported to tune the Tc of seed micelles by using metal ions as additives, rather than varying the chemical structure of BCPs. A pair of BCPs of OPV5‐b‐P2VP42 and OPV5‐b‐PNIPAM49 (OPV = oligo(p‐phenylene vinylene), P2VP = poly(2‐vinylpyridine), PNIPAM = poly(N‐isopropyl acrylamide), subscripts are the number of repeat unit for each block) as models. The Tc of seed micelles of OPV5‐b‐P2VP42 is significantly enhanced by adding Cu2+ ions, owing to the coordination of pyridyls to Cu2+ ions, whereas the Tc of seed micelles of OPV5‐b‐PNIPAM49 is hardly affected by Cu2+ ions with the presence of P2VP chains. In this way, the length and distribution of corona‐forming chains of resulting fiber‐like comicelles can be easily tuned by the addition of Cu2+ ions. [ABSTRACT FROM AUTHOR]

In this work, it is demonstrated for the first time that heterojunction nanowires, consisting of a gradient and segmented‐like heterogeneous π‐conjugated core with controllable length, composition and morphology, can be generated by co‐self‐seeding of oligo(p‐phenylene vinylene) (OPV)‐ and oligo(p‐phenylene ethynylene) (OPE)‐containing block copolymers in spite of different chain lengths and molecular conformation for OPE and OPV. More importantly, based on the understanding of the formation of heterogeneous core by the co‐self‐seeding approach, a "heating/cooling" seeded growth route was developed, by which linear and branched heterojunction nanowires containing a segmented heterogeneous π‐conjugated core of controlled length, composition and morphology can be obtained. This work provides a versatile platform to generate heterojunction nanowires with excellent controllability in length, composition, and morphology. [ABSTRACT FROM AUTHOR]

Ordered porous membranes have wide and important application prospects in the fields of filtration, separation, catalysis, biomedicine, etc., and have attracted growing interest in the field of material science. Among diverse membrane preparation approaches, breath pattern method has been widely concerned due to its simplicity in the preparation, ease in tuning the structure/property and functionality of formed membranes, and broad utility for various polymers. With the development of material design, the application spectrum of breath figure membrane has been greatly expanded. However, since the pore morphology of porous membrane is influenced by many factors, the controlling mechanism of normalization has not been clear yet. In this paper, the research progress of film‐forming materials in recent years is reviewed, and the correlation between pore formation and pore morphology is discussed in details. This information will provide a systematic and in‐depth perspective for research in this filed and an important guideline for the preparation of the ordered porous films with divergent applications. [ABSTRACT FROM AUTHOR]

As the world moves toward electromobility, our daily lives are flooded with variety of lithium ion batteries (LIBs), and the concerns of cost, safety and environmental friendliness of LIBs spring up in the minds of scientists. Although organic electrodes have been considered as promising alternatives to their inorganic counterparts, some intrinsic weaknesses still plague scientists, such as high solubility, low conductivity and sluggish ion diffusion. The emergence of covalent organic frameworks (COFs) attracts our attention because of their robust networks and open pores that could facilitate the infiltration of electrolyte ions when used as electrodes for metal‐ion batteries (MIBs). In this review, we summarized the recent progress of COFs as electrode materials, and the strategies toward enhancing electrochemical performance of COF‐based electrode in MIBs are discussed. Hopefully, this review will provide a fundamental guidance for future development of COF‐based electrodes. [ABSTRACT FROM AUTHOR]

Fiber‐like π‐conjugated nanostructures are important components of flexible organic electronic and optoelectronic devices. To broaden the range of potential applications, one needs to control not only the length of these nanostructures, but the introduction of diverse functionality with spatially selective control. Here we report the synthesis of a crystalline‐coil block copolymer of oligo(p‐phenylenevinylene)‐b‐poly(2‐vinylpyridine) (OPV5‐b‐P2VP44), in which the basicity and coordinating/chelating ability of the P2VP segment provide a landscape for the incorporation of a variety of functional inorganic NPs. Through a self‐seeding strategy, we were able to prepare monodisperse fiber‐like micelles of OPV5‐b‐P2VP44 with lengths ranging from 50 to 800 nm. Significantly, the exposed two ends of OPV core of these fiber‐like micelles remained active toward further epitaxial deposition of OPV5‐b‐PNIPAM49 and OPV5‐b‐P2VP44 to generate uniform A‐B‐A and B‐A‐B‐A‐B segmented block comicelles with tunable lengths for each block. The P2VP domains in these (co‐)micelles can be selectively decorated with inorganic and polymeric nanoparticles as well as metal oxide coatings, to afford hybrid fiber‐like nanostructures. This work provides a versatile strategy toward the fabrication of narrow length dispersity continuous and segmented π‐conjugated OPV‐containing fiber‐like micelles with the capacity to be decorated in a spatially selective way with varying functionalities. [ABSTRACT FROM AUTHOR]

Fiber‐like π‐conjugated nanostructures are important components of flexible organic electronic and optoelectronic devices. To broaden the range of potential applications, one needs to control not only the length of these nanostructures, but the introduction of diverse functionality with spatially selective control. Here we report the synthesis of a crystalline‐coil block copolymer of oligo(p‐phenylenevinylene)‐b‐poly(2‐vinylpyridine) (OPV5‐b‐P2VP44), in which the basicity and coordinating/chelating ability of the P2VP segment provide a landscape for the incorporation of a variety of functional inorganic NPs. Through a self‐seeding strategy, we were able to prepare monodisperse fiber‐like micelles of OPV5‐b‐P2VP44 with lengths ranging from 50 to 800 nm. Significantly, the exposed two ends of OPV core of these fiber‐like micelles remained active toward further epitaxial deposition of OPV5‐b‐PNIPAM49 and OPV5‐b‐P2VP44 to generate uniform A‐B‐A and B‐A‐B‐A‐B segmented block comicelles with tunable lengths for each block. The P2VP domains in these (co‐)micelles can be selectively decorated with inorganic and polymeric nanoparticles as well as metal oxide coatings, to afford hybrid fiber‐like nanostructures. This work provides a versatile strategy toward the fabrication of narrow length dispersity continuous and segmented π‐conjugated OPV‐containing fiber‐like micelles with the capacity to be decorated in a spatially selective way with varying functionalities. [ABSTRACT FROM AUTHOR]

Crystallization-driven self-assembly (CDSA) of block copolymers (BCPs) with a crystallizable core-forming oligo(p -phenylenevinylene) (OPV) segment can be a powerful strategy for the preparation of uniform fiber-like nanostructures containing a π-conjugated core with controlled dimension and composition. However, the self-assembly landscape can be complex, and our understanding of the nucleation and growth processes in the CDSA of BCPs with a crystalline π-conjugated segment is limited. We used fluorescence spectroscopy and 1H NMR to follow the self-assembly of oligo(p -phenylenevinylene)- b -poly(N -isopropyl acrylamide) (OPV 5 - b -PNIPAM 49), a typical π-conjugated-coil BCP, as solution of the BCP in ethanol is cooled from 80 °C to 23 °C and allowed to age, µDSC to monitor the crystallization exotherm, and DLS and TEM to follow micelle growth. We see a striking difference in the experiments that monitor unimer in solution comparing to those that monitor micelle growth. We see nearly complete disappearance of unimer within 30 min upon cooling. In contrast, the micelles continue to grow, increasing in length by a factor of ten over the next several hours. We are able to exclude growth by end-to-end coupling. We propose a self-assembly mechanism in which short semi-crystalline rod-like micelles form upon cooling, accompanied by small amorphous aggregates. Unimers that dissociate from these aggregates subsequently deposit on the growing ends of the core-crystalline micelles. We also find that the length of the PNIPAM block affects the elongation kinetics of OPV 5 - b -PNIPAM. [ABSTRACT FROM AUTHOR]

This article reports a new ferrocene/disulfide-containing methacrylate monomer and its nanocomposite via surface-initiated ATRP. • A new ferrocene/disulfide-containing methacrylate monomer, FcMAss, was prepared through successive esterification. • PFcMAss homopolymer and PEG- b -PFcMAss diblock copolymer were prepared via ATRP. • Graphene oxide-based nanocomposite was prepared by surface-initiated ATRP of FcMAss via the grafting-from strategy. A new methacrylate monomer containing ferrocene unit and disulfide bond, 2-((2-(methacryloyloxy)ethyl)disulfanyl)ethyl ferrocenecarboxylate (FcMAss), was prepared by subsequent esterification reaction with bis(2-hydroxyethyl) disulfide and methacryloyl chloride using ferrocenecarboxylic acid as starting material. A series of well-defined poly(2-((2-(methacryloyloxy)ethyl)disulfanyl)ethyl ferrocenecarboxylate) (PFcMAss) homopolymers with narrow molecular weight distributions (M w / M n < 1.30) was then obtained by atom transfer radical polymerization (ATRP) of FcMAss monomer in toluene. Block copolymerization of FcMAss monomer was initiated by PEG-Br macroinitiator in THF to afford a poly(ethylene glycol)- b -poly(2-((2-(methacryloyloxy)ethyl)disulfanyl)ethyl ferrocenecarboxylate) (PEG- b -PFcMAss) diblock copolymer with a relatively low dispersity (M w / M n = 1.34). Graphene oxide (GO)-based nanocomposite, GO-PFcMAss, was prepared by surface-initiated ATRP of FcMAss via the grafting-from strategy, using GO-based macroinitiator obtained by treating tris(hydroxymethyl) aminomethane (TRIS)-modified GO with 2-bromo-2-methylpropionyl bromide. The nanocomposite was characterized by FT-IR and XPS, and showed excellent dispersibility and colloidal stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • A facile platform toward nanofibers containing a heterogeneous π-conjugated core with controlled length/composition/morphology is developed. • The effect and mechanism behind of initial structure of seed (co)micelles on co-self-seeding behavior has been disclosed for the first time. • Various nanofibers containing a heterogeneous π-conjugated core can be generated by co-self-seeding with varying seeds/temperature. Co-self-seeding approach of living crystallization-driven self-assembly (CDSA) enables the generation of fiber-like micelles with a π-conjugated core of tunable length/composition/ morphology with appealing photophysical and photochemical properties. However, our understanding on the co-self-seeding strategy in the preparation of fiber-like comicelles containing a heterogeneous π-conjugated core is limited owing to very rare reports associated to this recently emerging strategy. Herein, we report that polydisperse comicelles containing a heterogeneous OPE 9 /OPV 5 (OPE = oligo(p -phenylene ethynylene), OPV = oligo(p -phenylene vinylene), the subscripts indicate the exact number of repeat unit of OPE and OPV segments) core can be formed from the mixture of OPE 9 - b -P2VP 56 and OPV 5 - b -PNIPAM 47 (P2VP = poly(2-vinylpyridine), PNIPAM = poly(N -isopropylacrylamide), the subscripts denote the degree of polymerization) with different mass ratios of OPE 9 - b -P2VP 56 to OPV 5 - b -PNIPAM 47 (M OPE9 / M OPV5) by crystallization-driven co-self-assembly via heating/cooling protocol. Subsequently, by co-self-seeding from the seed comicelles obtained by the fragmentation of as-prepared polydisperse comicelles, apparent continuous (gradient) and segmented (block) fiber-like comicelles containing a heterogeneous OPE 9 /OPV 5 core of controlled length/composition/morphology can be generated with varying annealing temperature and M OPE9 / M OPV5. Co-self-seeding from pairs of separated seed micelles of OPE 9 - b -P2VP 56 and OPV 5 - b -PNIPAM 47 with different M OPE9 / M OPV5 also can give apparently continuous and segmented fiber-like comicelles containing a heterogeneous OPE 9 /OPV 5 core. These two co-self-seeding approaches have some common and different characteristics. It is found that for these samples with the M OPE9 / M OPV5 = 1/1 and 2/1, the L n of comicelles obtained from seed comicelles showed much sharper increase with the increase of temperature relative to the L n of comicelles generated from mixed seed micelles as the temperatures were above 70 °C. On the contrary, for the M OPE9 / M OPV5 = 5/1, both sets of samples showed very similar trend of dependence of L n of resulting comicelles on the annealing temperature. These results revealed that both packing modes and mass ratios (M OPE9 / M OPV5) of seed (co)micelles affected the co-self-seeding behavior. [ABSTRACT FROM AUTHOR]

A novel oridonin derivative substituted with 3-((2,3-dihydroxypropyl)dithio)-propionyl group at 14- O position was synthesized through a two-step procedure: Esterification of oridonin with 3-(2-pyridyldithio)propanoic acid and the subsequent thiol-disul?de exchange reaction with 3-mercapto-1,2-propanediol. The bioreduction-responsive disulfide bond in the compound leads to high leaving ability of the 14- O acyl moiety when treated with glutathione as monitored by reverse phase high-performance liquid chromatography. [ABSTRACT FROM AUTHOR]

A series of well-defined amphiphilic graft copolymers bearing hydrophilic poly(ethylene oxide) (PEO) side chains with tunable grafting densities were synthesized by atom transfer nitroxide radical coupling (ATNRC) reaction using CuBr/PMDETA as catalytic system via the grafting-onto strategy. PEO side chains were linked to α-C of carbonyl of polyacrylate-based backbone, not to the ester side groups as usual, so that every repeating unit of the backbone possessed a pendant steric bulky tert-butyl group. The critical micelle concentrations of the obtained amphiphilic graft copolymers in aqueous media determined by fluorescence probe technique using pyrene as probe increased with the raising of molecular weights. These amphiphilic graft copolymers with novel chemical structure showed unprecedented diverse nanostructures visualized by transmission electron microscopy in aqueous media and micellar morphologies varied with the changing of experiment parameters. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 [ABSTRACT FROM AUTHOR]

A series of new well-defined amphiphilic graft copolymers containing hydrophobic poly( tert-butyl acrylate) backbone and hydrophilic poly(ethylene oxide) side chains were reported. Reversible addition-fragmentation chain transfer homopolymerization of tert-butyl 2-((2-bromopropanoyloxy)methyl)acrylate was first performed to afford a well-defined backbone with a narrow molecular weight distribution ( Mw/ Mn = 1.07). The target poly( tert-butyl acrylate)- g-poly(ethylene oxide) (P tBA- g-PEO) graft copolymers with low polydispersities ( Mw/ Mn = 1.18-1.26) were then synthesized by atom transfer nitroxide radical coupling or single electron transfer-nitroxide radical coupling reaction using CuBr(Cu)/PMDETA as catalytic system. Fluorescence probe technique was employed to determine the critical micelle concentrations ( cmc) of the obtained amphiphilic graft copolymers in aqueous media. Furthermore, PAA- g-PEO graft copolymers were obtained by selective acidic hydrolysis of hydrophobic P tBA backbone while PEO side chains kept inert. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 [ABSTRACT FROM AUTHOR]

A series of ferrocene-based well-defined amphiphilic graft copolymers, consisting of hydrophilic poly[poly(ethylene glycol) methyl ether acrylate] (PPEGMEA) backbone and hydrophobic poly(2-acryloyloxyethyl ferrocenecarboxylate) (PAEFC) side chains were synthesized by successive single-electron-transfer living radical polymerization (SET-LRP) and atom transfer radical polymerization (ATRP). The backbone was prepared by SET-LRP of PEGMEA macromonomer, and it was then treated with lithium di-isopropylamide and 2-bromopropionyl bromide at −78 °C to give PPEGMEA-Br macroinitiator. The targeted well-defined graft copolymers with narrow molecular weight distributions ( Mw/ Mn ≤ 1.32) were synthesized via ATRP of AEFC initiated by PPEGMEA-Br macroinitiator, and the molecular weights of the backbone and side chains were both controllable. The electro-chemical behaviors of graft copolymers were studied by cyclic voltammetry, and it was found that graft copolymers were more difficult to be oxidized, and the reversibility of electrode process became less with raising the content of PAEFC segment. The effects of the preparation method, the length of hydrophobic PAEFC segment, and the initial water content on self-assembly behavior of PPEGMEA- g-PAEFC graft copolymers in aqueous media were investigated by transmission electron microscopy. The morphologies of micelles could transform from cylinders to spheres or rods with changing the preparation condition and the length of side chains. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 [ABSTRACT FROM AUTHOR]

A series of well-defined double hydrophilic graft copolymers containing poly(poly(ethylene glycol) methyl ether acrylate) (PPEGMEA) backbone and poly(2-vinylpyridine) (P2VP) side chains were synthesized by successive single electron transfer living radical polymerization (SET-LRP) and atom transfer radical polymerization (ATRP). The backbone was first prepared by SET-LRP of poly(ethylene glycol) methyl ether acrylate (PEGMEA) macromonomer using CuBr/tris(2-(dimethylamino)ethyl)amine as catalytic system. The obtained homopolymer then reacted with lithium diisopropylamide and 2-chloropropionyl chloride at −78 °C to afford PPEGMEA-Cl macroinitiator. poly(poly(ethylene glycol) methyl ether acrylate)- g-poly(2-vinylpyridine) double hydrophilic graft copolymers were finally synthesized by. ATRP of 2-vinylpyridine initiated by PPEGMEA-Cl macroinitiator at 25 °C using CuCl/hexamethyldiethylenetriamine as catalytic system via the grafting- from strategy. The molecular weights of both the backbone and the side chains were controllable and the molecular weight distributions kept relatively narrow ( Mw/ Mn ≤ 1.40). pH-Responsive micellization behavior was investigated by 1H NMR, dynamic light scattering, and transmission electron microscopy and this kind of double hydrophilic graft copolymer aggregated to form micelles with P2VP-core while pH of the aqueous solution was above 5.0. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 [ABSTRACT FROM AUTHOR]

A series of well-defined amphiphilic graft copolymers bearing hydrophobic poly( tert-butyl acrylate) backbone and hydrophilic poly[poly(ethylene glycol) methyl ether methacrylate)] (PPEGMEMA) side chains were synthesized by sequential reversible addition fragmentation chain transfer (RAFT) polymerization and single-electron-transfer living radical polymerization (SET-LRP) without any polymeric functional group transformation. A new Br-containing acrylate monomer, tert-butyl 2-((2-bromoisobutanoyloxy)methyl)acrylate ( tBBIBMA), was first prepared, which can be homopolymerized by RAFT to give a well-defined P tBBIBMA homopolymer with a narrow molecular weight distribution ( Mw/ Mn = 1.15). This homopolymer with pendant Br initiation group in every repeating unit initiated SET-LRP of PEGMEMA at 45 °C using CuBr/dHbpy as catalytic system to afford well-defined P tBBIBMA- g-PPEGMEMA graft copolymers via the grafting-from strategy. The self-assembly behavior of the obtained graft copolymers in aqueous media was investigated by fluorescence spectroscopy and TEM. These copolymers were found to be stimuli-responsive to both temperature and ions. Finally, poly(acrylic acid)- g-PPEGMEMA double hydrophilic graft copolymers were obtained by selective acidic hydrolysis of hydrophobic P tBA backbone while PPEGMEMA side chains kept inert. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 [ABSTRACT FROM AUTHOR]

Two new amphiphilic star graft copolymers bearing hydrophobic poly( tert-butyl acrylate) backbone and hydrophilic poly(ethylene oxide) (PEO) side chains with different molecular weights were synthesized by sequential reversible addition fragmentation chain transfer (RAFT) polymerization and single electron transfer-nitroxide radical coupling (SET-NRC) reaction under mild conditions. RAFT homopolymerization of tert-butyl 2-((2-bromopropanoyloxy)methyl)acrylate was mediated by a four-armed chain transfer agent in a controlled way to afford a well-defined starlike backbone with a narrow molecular weight distribution ( Mw/ Mn = 1.26). The target poly( tert-butyl acrylate)- g-PEO (P tBA- g-PEO) star graft copolymers were synthesized by SET-NRC reaction between Br-containing P tBA-based starlike backbone and PEO end functionalized with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) group using copper/ N, N, N′, N′, N″-pentamethyldiethylenetriamine as catalytic system at ambient temperature via grafting-onto strategy. The critical micelle concentration values of the obtained amphiphilic star graft copolymers in aqueous media and brine were determined by fluorescence probe technique using pyrene as probe. Diverse micellar morphologies were formed by varying the content of hydrophilic PEO segment as well as the initial concentration of stock solution. In addition, poly(acrylic acid)- g-PEO double hydrophilic star graft copolymers were obtained by selective acidic hydrolysis of hydrophobic P tBA starlike backbone without affecting PEO side chains. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 [ABSTRACT FROM AUTHOR]

Abstract: A new methacrylate monomer containing perfluorocyclobutyl and sulfonyl units, p-(2-(p-(benzenesulfonyl)phenoxy)perfluorocyclobutoxy)phenyl methacrylate, was synthesized from commercially available reagents in good yield and this kind of methacrylate can be homopolymerized by free radical polymerization using 2,2′-azobis(isobutyronitrile) as initiator or atom transfer radical polymerization using methyl 2-bromopropionate as initiator and CuBr/PMDETA as catalytic system. The reactivity ratios for BSPPFCBPMA and MMA were found to be r 1 =1.2436 and r 2 =0.8171 determined by Fineman–Ross method, and r 1 =1.2279 and r 2 =0.8023 by Kelen–Tudos method respectively. The resultant polymethacrylates bearing perfluorocyclobutyl and sulfonyl functionalities exhibit excellent thermal stability as evidenced from thermogravimetric analysis and the decomposition temperature rose dramatically with the increasing of molecular weights. Random copolymers of BSPPFCBPMA and methyl methacrylate were obtained by free radical copolymerization and their thermo-stabilities increase while raising the contents of BSPPFCBPMA. [Copyright &y& Elsevier]

Abstract: Poly(N-isopropylacrylamide)-b-[poly(ethyl acrylate)-g-poly(2-(diethylamino)ethyl methacrylate)] (PNIPAM-b-(PEA-g-PDEAEMA)) double hydrophilic graft copolymers were employed to prepare stable colloidal gold nanoparticles in situ with controllable size in aqueous media without any external reducing agent. PDEAEMA side chains served as reduction agent and stabilizer and PNIPAM segment acted as a hydrated layer to enhance the stability of gold nanoparticles. These gold nanoparticles showed a remarkable colloidal stability without any observable flocculation or aggregation for at least 2 months and they were characterized by UV–vis, XRD, TEM and AFM in detail. The size of gold nanoparticles can be tuned by adjusting the length of PDEAEMA side chains and the molar ratio of [DEAEMA]/[AuCl4 −]. Both the increasing of the length of PDEAEMA side chains and the decreasing of [DEAEMA]/[AuCl4 −] molar ratio resulted in the fall of size. [Copyright &y& Elsevier]

Abstract: We present the synthesis and self-assembly behavior of a new semi-fluorinated amphiphilic triblock copolymer. A series of perfluorocyclobutyl aryl ether-based amphiphilic ABA triblock copolymer containing hydrophilic poly(ethylene glycol) segment as the middle block were synthesized by atom transfer radical polymerization (ATRP). ATRP of 4-(4′-p-tolyloxyperfluorocyclobutoxy)benzyl methacrylate was initiated by PEG-based bifunctional macroinitiators with different molecular weights to obtain the desired copolymers with narrow molecular weight distributions (M w/M n ≤1.30) and the number of perfluorocyclobutyl linkage can be tuned by the feed ratio and the conversion of the fluorine-containing methacrylic monomer. The critical micelle concentrations of these amphiphilic ABA triblock copolymers in aqueous media were determined by fluorescence probe technique. They could aggregate to form spherical and cylindrical micelles visualized by TEM with varying the content of hydrophobic segment. [Copyright &y& Elsevier]

A series of well‐defined double‐hydrophilic graft copolymers, consisting of poly(N‐isopropylacrylamide)‐b‐poly(ethyl acrylate) (PNIPAM‐b‐PEA) backbone and poly(2‐(dimethylamino)ethyl acrylate) (PDMAEA) side chains, were synthesized by the combination of single‐electron‐transfer living radical polymerization (SET‐LRP) and atom‐transfer radical polymerization (ATRP). PNIPAM‐b‐PEA backbone was first prepared by sequential SET‐LRP of N‐isopropylacrylamide and 2‐hydroxyethyl acrylate at 25 °C using CuCl/tris(2‐(dimethylamino)ethyl)amine as catalytic system followed by the transformation into the macroinitiator by treating the pendant hydroxyls with 2‐chloropropionyl chloride. The final graft copolymers with narrow molecular weight distributions were synthesized by ATRP of 2‐(dimethylamino)ethyl acrylate initiated by the macroinitiator at 40 °C using CuCl/tris(2‐(dimethylamino)ethyl)amine as catalytic system via the grafting‐from strategy. These copolymers were employed to prepare stable colloidal gold nanoparticles with controlled size in aqueous solution without any external reducing agent. The morphology and size of the nanoparticles were affected by the length of PDMAEA side chains, pH value, and the feed ratio of the graft copolymer to HAuCl4. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1811–1824, 2009 [ABSTRACT FROM AUTHOR]

Abstract: A new class of methacrylate monomers containing perfluorocyclobutyl unit was synthesized in multi-steps including crossing-dimerization, demethylation and esterification using commercially available p-substituted phenol, tetrafluoroethylene and methacryloyl chloride as starting materials. These monomers can be polymerized in solution to provide perfluorocyclobutyl-based polymethacrylate, a kind of potential transparent material. [Copyright &y& Elsevier]

Abstract: Perfluorocyclobutyl aryl ether-based amphiphilic diblock copolymer containing hydrophilic poly(ethylene glycol) segment was synthesized by atom transfer radical polymerization (ATRP). Perfluorocyclobutyl-containing methacrylate-based monomer, 4-(4′-p-tolyloxyperfluorocyclobutoxy)benzyl methacrylate, was prepared firstly, which can be polymerized by ATRP in a controlled way to obtain well-defined homopolymers with narrow molecular weight distributions (M w/M n ≤1.30). The molecular weights increased linearly with the conversions of monomer and the apparent polymerization rate exhibited first-order relation with respect to the concentration of monomer. ATRP of 4-(4′-p-tolyloxyperfluorocyclobutoxy)benzyl methacrylate was initiated by PEG-based macroinitiators with different molecular weights to obtain amphiphilic diblock copolymers with narrow molecular weight distributions (M w/M n <1.35) and the number of perfluorocyclobutyl linkage can be tuned by the feed ratio and the conversion of the fluorine-containing methacrylate monomer. The critical micelle concentrations of these amphiphilic diblock copolymers in water and brine were determined by fluorescence probe technique. The morphologies of the micelles were found to be spheres by TEM. [Copyright &y& Elsevier]

Abstract: A new polyradical containing polyallene backbone and stable pendant nitroxyl radicals was synthesized using 4-hydroxyl-2,2,6,6-tetramethylpiperidine as starting material. Firstly, a new allenyl ether monomer, 4-allenyloxyl-2,2,6,6-tetramethyl piperidine was prepared by 2 steps. Next, BPO initiated the traditional free radical polymerization of 4-allenyloxyl-2,2,6,6-tetramethyl piperidine at 100°C to obtain the homopolymer, poly(4-allenyloxyl-2,2,6,6-tetramethyl piperidine). Finally, the homopolymer was quantitatively oxidized by H2O2/Na2WO4·2H2O/EDTA at room temperature to yield the final product, poly(4-allenyloxyl-2,2,6,6-tetramethyl piperidine-1-oxyl). Studies on the electrochemical properties of polyradical showed excellent charging/discharging reversibility and stability with a high columbic efficiency of 98%, which suggested that the synthesized polyradical is a promising cathode material for lithium secondary battery. [Copyright &y& Elsevier]

Abstract: A series of well-defined graft copolymers with a polyallene-based backbone and poly(methyl methacrylate) side chains were synthesized by the combination of living coordination polymerization of 6-methyl-1,2-heptadien-4-ol and atom transfer radical polymerization of methyl methacrylate. We first prepared poly(alcohol) with polyallene repeating units via 6-methyl-1,2-heptadien-4-ol by living coordination polymerization initiated by [(η3-allyl)NiOCOCF3]2, followed by transforming the pendant hydroxyl groups into halogen-containing ATRP initiation groups. Next, grafting-from route was used for the synthesis of the well-defined graft copolymer with excellent solubility: poly(methyl methacrylate) was grafted to the backbone via ATRP of methyl methacrylate. This kind of graft copolymer is the first example of graft copolymer via allene derivative and methacrylic monomer. [Copyright &y& Elsevier]

Abstract: A series of well-defined amphiphilic graft copolymers containing hydrophilic poly(acrylic acid) backbones and hydrophobic poly(methyl methacrylate) side chains were synthesized by successive atom transfer radical polymerization followed by the selective hydrolysis of poly(methoxymethyl acrylate) backbone. Grafting-from strategy was employed for the synthesis of graft copolymers with narrow molecular weight distributions. Hydrophobic side chains were connected with the backbone through stable C–C bonds instead of ester connections. The backbone can be easily hydrolyzed to poly(acrylic acid) with HCl without affecting the hydrophobic side chains. The amphiphilic graft copolymers can form stable micelles in water. The critical micelle concentration was determined by fluorescence spectroscopy. The micellar morphologies were found to be vesicles by transmission electron microscopy and changed to spheres with the addition of NaCl. [Copyright &y& Elsevier]

Abstract: A novel sulfonyl-containing monomer, 4,4′-sulfonyl-bis(trifluorovinyloxy)biphenyl, and the resulting fluoropolymers with good thermal stability have been prepared. The monomer was synthesized by two steps using 4,4′-sulfonyldiphenol as starting material and characterized by FT-IR, 1H NMR, 13C NMR, 19F NMR and element analysis in detail. Fluoropolymers containing sulfonyl and perfluorocyclobutyl units were prepared by different polymerization methods. A series of fluoropolymers with higher molecular weights were obtained by solution polymerization in diphenyl ether. The molecular weight is dependent on the polymerization time, polymerization temperature and the concentration of the monomer. The resulting polymers show excellent solubility in conventional solvents and good thermal stability with a high decomposition temperature about 500°C measured by TGA. [Copyright &y& Elsevier]

We report a versatile route to prepare functional inorganic nanotubes by using uniform fiber-like micelles of controlled length containing a photo-cleavable core as templates. [Display omitted] • Uniform nanofibers containing a crystalline π-conjugated OPV, a P2VP corona and a photo-cleavable junction were generated by living CDSA. • The resulting nanofibers can serve as a versatile template to fabricate inorganic nanotubes of controlled length. • Pt(0)-embedded silica nanotubes exhibited much higher catalytic activity as a consequence of the presence of porous channel. Inorganic nanotubes with unique and well-defined porous structures show promising applications in diverse functional materials. However, it remains a challenge to fabricate inorganic nanotubes with precise length controllability. Herein, we report the synthesis of block copolymers consisting of a crystalline π-conjugated oligo(p -phenylenevinylene) (OPV) block, a hydrophilic poly(2-vinylpyridine) (P2VP) segment and a photo-cleavable o -nitrobenzyl (ONB) junction. By taking advantage of crystallinity of OPV segment, self-seeding approach of living crystallization-driven self-assembly was employed to generate uniform fiber-like micelles composed of an OPV core and a P2VP corona. The P2VP corona was then used to host the formation of silica, titania and Pt(0)-embedded silica shell. After the photo-cleavable OBN junctions were broken under light irradiation, the OPV core can be removed in a good solvent for OPV segments to give silica, titania and Pt(0)-embedded silica nanotubes. Significantly, the Pt(0)-embedded silica nanotubes exhibited much higher catalytic activity toward the reduction of p -nitroaniline than Pt(0)-embedded silica nanofibers with the same Pt content, probably owing to the presence of porous channel for nanotubes. This work opens a new avenue to fabricate inorganic nanotubes of controlled length. [ABSTRACT FROM AUTHOR]

This article reports new perfluorocyclobutyl aryl ether-containing methacrylates for thermo-stable and transparent polymethacrylates via radical polymerization. • Three semi-fluorinated methacrylates bearing perfluorocyclobutyl aryl ether moiety were prepared. • PPF n MA homopolymers with high molecular weight were prepared via solution free radical polymerization. • The resulting semi-fluorinated polymethacrylates exhibit good solubility in common organic solvents and high transparency in the visible light range. Three fluorine-containing methacrylate monomers consisting of one, two and three perfluorocyclobutyl (PFCB) aryl ether moieties were designed and synthesized through the esterification reaction between methacryloyl chloride and corresponding intermediates bearing different numbers of PFCB aryl ether moieties, which were achieved via an iterative elongation methodology. Subsequently, these methacrylate monomers were polymerized via conventional free radical polymerization in solution using AIBN as initiator to provide a series of polymethacrylate homopolymers with excellent solubility, whose repeat units contain one, two or three PFCB aryl ether moieties. The influence of the number of PFCB aryl ether moiety in each repeat unit on the light transmittance and surface wettability of the corresponding polymethacrylates were investigated by UV/vis spectroscopy and static water contact angle test. The results indicated that these polymethacrylates containing PFCB aryl ether moieties exhibit high transparency and strong hydrophobicity. It was also found from the results of thermogravimetry analysis that the initial decomposition temperatures of the resulting semi-fluorinated polymethacrylates comprising two and three PFCB aryl ether moieties are approaching 350 °C, which is much higher than that of common poly(methyl methacrylate), indicative of higher thermal stability of semi-fluorinated polymethacrylates in the presence of PFCB aryl ether moieties. [ABSTRACT FROM AUTHOR]

A facile strategy to prepare GO-based nanocomposites with both gold nanoparticles (AuNPs) and ferrocene (Fc) moieties was developed. The surface of GO was modified with PFcMAss homopolymer by surface-initiated atom transfer radical polymerization of a new methacrylate monomer of 2-((2-(methacryloyloxy)ethyl)disulfanyl)ethyl ferrocene-carboxylate (FcMAss), consisting of disulfide as an anchoring group for stabilizing AuNPs and Fc group as an additional functionality. AuNPs with an average diameter of about 4.1 nm were formed in situ on the surface of PFcMAss-decorated GO (GO-PFcMAss) via Brust-Schiffrin method to give GO-PFcMAss-AuNPs multifunctional nanocomposites bearing GO, AuNPs and Fc groups. The obtained nanocomposites were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Since disulfide-containing polymers, rather than the commonly used thiol-containing compounds, were employed as ligands to stabilize AuNPs, much more stabilizing groups were attached onto the surface of GO, and thus more AuNPs were able to be introduced onto the surface of GO. Besides, polymeric chains on the surface of GO endowed GO-PFcMAss-AuNPs nanocomposites with excellent colloidal stability, and the usage of a disulfide group provides possibility to efficiently incorporate additional functionalities by easily modifying structure of disulfide-based monomer. [ABSTRACT FROM AUTHOR]

The cover page of the journal "Chinese Journal of Chemistry" is presented.

In this paper, we propose a novel readout circuit based on a buffered-direct-injection structure. In this new readout circuit, all the pixels in one row can start to integrate simultaneously. And the readout time can be reduced by as much as 94%. Since readout time in many conventional readout circuits contributes to half of the total row selection time, it is directly proportional to the total frame time. And the output waveform is boxcar, which is very easy to AD convert. In addition, one current storage cell is added into the readout circuit to achieve in-pixel background current suppression to remove the background component inherent in each pixel output. To increase the current mirror accuracy and the integration dynamic range, a cascode current mirror is also adopted in the readout circuit. SPICE simulation results have shown that the proposed readout circuit can achieve high charge sensitivity and resolution in a large format IRFPA with small pixel size. [ABSTRACT FROM AUTHOR]