Water-soluble Hyperbranched Poly Research Articles

A functional hyperbranched binder enabling ultra-stable sulfur cathode for high-performance lithium-sulfur battery

Abstract Binders are of vital importance in stabilizing the cathodes to enhance the cycling stability of lithium-sulfur (Li-S) batteries. However, conventional binders are typically confronted with the drawback of inability for adsorbing lithium polysulfide (LiPS), thus resulting in severe active material losing and rapid capacity fading. Herein, a novel water-soluble hyperbranched poly(amidoamine) (HPAA) binder with controllable hyperbranched molecular structure and abundant amino end groups for Li-S battery is designed and fabricated, which can improve efficient adsorption for LiPS and stability of the sulfur cathodes. Besides, the strong intermolecular hydrogen bonds in HPAA binder can contribute to the structural stability of S cathode and integration of the conductive paths. Therefore, the Li-S battery with this functional binder exhibits excellent cycle performance with a capacity retention of 91% after 200 cycles at 0.1 C. Even at a high sulfur loading of 5.3 mg cm−2, a specific capacity of 601 mA h g−1 can also be achieved. Density functional theory (DFT) calculation further demonstrates that the enhanced electrochemical stability derives from the high binding energy between amino groups and LiPS and the wide electrochemical window (6.87 eV) of HPAA molecule. Based on the above all, this functional polymer will lighten a new species of binders for eco-friendly sulfur cathodes and significantly promote the practical applications of high-performance Li-S batteries.

A simple and convenient route to synthesize novel hyperbranched Poly(amine ester) with multicolored fluorescence

Multicolored fluorescence stemed from the nonconventional luminescent polymers without aromatic units is an interesting and meaningful property. So far, a few such polymers bearing multicolored fluorescence are reported; its species, however, are relatively little. Herein, we synthesized a kind of novel water-soluble hyperbranched poly(amine ester) (HPAE) via a straightforward transesterification polycondensation reaction using inexpensive and easily available chemicals. Intriguingly, the pure HPAE could emit blue, green and red luminescence when irradiated by different excitation wavelengths. The TEM result shows that the synergy effect of intra-/intermolecular hydrogen bonds and hydrophobic effect could induce the HPAE to self-assemble and form supramolecular HPAE in water. Such supramolecular HPAE further promote to form stronger through-space conjugation, thus which is favourable for the emission. In addition, the significant solvent and pH dependence profiles of luminescence intensity are also observed. In particular, the HPAE can be used to detect metal ions, and there is strong selective quenching in respect of Fe3+. Therefore, the HPAE show a potential probe for Fe3+.

Water-soluble hyperbranched poly(phenyleneethynylene)s: Facile synthesis, characterization, and interactions with dsDNA

Two novel water-soluble hyperbranched poly(p-phenyleneethynylene)s (HBP1′ and HBP2′) bearing different contents of oligo(ethylene oxide) (OEO) side chains with ammonium end groups were synthesized by the facile “A2 + B2 (or A2′) + C3” protocol based on Sonogashira polymerization. Their linear analog (LP2′) was also synthesized for comparative investigation. The optical properties of the neutral precursory polymers in THF and final cationic conjugated polyelectrolytes (CCPs) in aqueous solution were studied. Compared with LP2′, HBP1′ exhibited increased water solubility and fluorescence quantum yield despite its lower charge density, and HBP2′, with the similar charge density as LP2′, showed the best water solubility and the highest fluorescence quantum yield among the three CCPs. This indicated that the introduction of hyperbranched structure into conjugated polyelectrolytes was an efficient way to improve water solubility and fluorescence quantum yield because intermolecular aggregation was remarkably prevented. The interactions among the three CCPs and double-stranded DNA (dsDNA) were studied using ethidium bromide (EB) as the fluorescent probe. The electrostatic bindings of the three CCPs with dsDNA/EB complex resulted in displacement of EB from dsDNA to the solution accompanied by the quenching of EB fluorescence. Both HBP1′ and HBP2′ bound to dsDNA more efficiently than LP2′, and HBP2′ formed the most stable complex with dsDNA, suggesting that dsDNA might enter the cavities of single-molecular globular architectures of these hyperbranched conjugated polyelectrolytes and induced additional host-guest spatial interactions. Hence, HBP1′ and HBP2′ may be proved very useful in gene delivery or DNA biosensor applications.

Synthesis of Water Soluble Hyperbranched Poly (amine-ester) as Corrosion Inhibitors for Steel

Synthesis of Water Soluble Hyperbranched Poly (amine-ester) as Corrosion Inhibitors for Steel

Surface-functionalized hyperbranched poly(amido acid) magnetic nanocarriers for covalent immobilization of a bacterial γ-glutamyltranspeptidase.

In this study, we synthesized water-soluble hyperbranched poly(amido acid)s (HBPAAs) featuring multiple terminal CO2H units and internal tertiary amino and amido moieties and then used them in conjunction with an in situ Fe2+/Fe3+ co-precipitation process to prepare organic/magnetic nanocarriers comprising uniformly small magnetic iron oxide nanoparticles (NP) incorporated within the globular HBPAAs. Transmission electron microscopy revealed that the HBPAA-γ-Fe2O3 NPs had dimensions of 6–11 nm, significantly smaller than those of the pristine γ-Fe2O3 (20–30 nm). Subsequently, we covalently immobilized a bacterial γ-glutamyltranspeptidase (BlGGT) upon the HBPAA-γ-Fe2O3 nanocarriers through the formation of amide linkages in the presence of a coupling agent. Magnetization curves of the HBPAA-γ-Fe2O3/BlGGT composites measured at 300 K suggested superparamagnetic characteristics, with a saturation magnetization of 52 emu g−1. The loading capacity of BlGGT on the HBPAA-γ-Fe2O3 nanocarriers was 16 mg g−1 support; this sample provided a 48% recovery of the initial activity. The immobilized enzyme could be recycled 10 times with 32% retention of the initial activity; it had stability comparable with that of the free enzyme during a storage period of 63 days. The covalent immobilization and stability of the enzyme and the magnetization provided by the HBPAA-γ-Fe2O3 NPs suggests that this approach could be an economical means of depositing bioactive enzymes upon nanocarriers for BlGGT-mediated bio-catalysis.

A synthetic approach for water soluble hyperbranched poly(N,N-ethylidenebis(N-2-chloroacetyl acrylamide)) with high degree of branching via atom transfer radical polymerization/self-condensing vinyl polymerization

A novel acrylamide A2B2* (A = alkene, B* = alkyl chlorine) type inimer was obtained from commercially available 1,2-ethylenediamine, chloroacetyl chloride and acryloyl chloride. The as-prepared monomer can form water-soluble hyperbranched poly(N,N-ethylidene bis(N-2-chloroacetyl acrylamide))s (HPECA) through atom transfer radical polymerization/self-condensing vinyl polymerization method in the presence alkyl chlorine/CuCl/2,2-bipyridine activation system which can effectively suppress the gelation formation. 1H-NMR spectra and dual detector size exclusion chromatography proved the hyperbranched structure indisputably, and the degree of branching was determined by the detailed analyses of 1H-NMR spectra. The trend of the degree of branching was in consistent with the result of Mark-Houwink exponent a. The experiment results suggested that the conversion was 67%, Mw = 13.2 × 104, Mark-Houwink a = 0.282 and the degree of branching = 64% when the reaction temperature was 120 °C, reaction time = 168 h and N,Nethylidene bis(N-2-chloroacetyl acrylamide):Cu(I) = 50:0.62.

Water-soluble hyperbranched poly(ester urethane)s based on d,l-alanine: isocyanate-free synthesis, post-functionalization and application

The green synthesis of a novel hyperbranched poly(ester urethane) (HBPEU) has been reported via an isocyanate-free method based on D,L-alanine and a lower-toxic cyclic carbonate monomer, glycerol carbonate. Benefiting from the efficient reaction between the amine and five-membered cyclic carbonate, an AB2-type monomer bearing urethane linkages has been quantitatively formed without using a toxic isocyanate species. Subsequent bulk polyesterification was carried out to give water-soluble HBPEUs with moderate molecular weights and a degree of branching (DB) in the range of 0.44–0.52. Furthermore, the polycaprolactone arms were grafted to the HBPEU core via ring-opening polymerization of e-caprolactone initiated by the peripheral hydroxyl groups around HBPEU, forming biodegradable and biocompatible amphiphilic star copolymers, which acts as an “unimolecular reverse micelle” in CHCl3. Two water soluble dyes, methyl orange and bromophenol blue, were successfully transported from water to the insoluble chloroform phase by the core–shell star polymers, indicating the great potential of the micelles as nanocarriers. The arm lengths and core sizes of the star polymers greatly influenced the dye-loading capacity of the nanocarrier.

Degradation of Hyper‐Branched Poly(ethylenimine)‐graft‐poly(caprolactone)‐block‐monomethoxyl‐poly(ethylene glycol) as a Potential Gene Delivery Vector

Water-soluble hyper-branched poly(ethylenimine)-graft-poly(caprolactone)-block-monomethoxyl-poly(ethylene glycol) cationic copolymers (hy-PEI-PCL-mPEG) have shown potential for gene delivery. The degradation behavior of this type of copolymer is studied. Effects of the molecular weight of the hyper-branched PEI (hy-PEI), and the length of the mPEG and PCL blocks are investigated. The degradation is mainly monitored by the changes of molecular weight by GPC-MALLS. The molecular weight changes of the copolymers in different aqueous solutions have been characterized as a function of incubation time at 37°C from 0 to 45 d. The micelle size and pH value have also been recorded accordingly to monitor the degradation in water. The investigation reveals that copolymers containing hy-PEI2k degrade faster than others containing hy-PEI10k and hy-PEI25k based on the same mPEG-PCL block, while copolymers those contain mPEG5k degrade faster than those containing mPEG2k and mPEG0.55k based on the same PCL segments and hy-PEI. An inhibitory effect of acidic conditions and acceleration in basic media have been found for degradation in different buffers. A higher ionic strength of the buffer accelerated the degradation. The molecular weight of copolymer is reduced to 95% within one day with 10 mg·mL(-1) of lipase while 70% remains with 5 mg·mL(-1) of lipase. These investigations suggest that the degradation of hy-PEI-PCL-mPEG can be designed and the degradation period is reasonable for gene-transfer in vivo.

Synthesis, characterisation and utilisation of hyperbranched poly (ester‐amide) for the removal of some anionic dyestuffs from their aqueous solutions

PurposeThe purpose of this paper is to show how to remove some dyestuffs, as pollutants, from their aqueous solutions.Design/methodology/approachTo achieve the goal, a water soluble hyperbranched poly (ester‐amide) (HBP) was synthesised using the melt polycondensation method by the reaction of maleic anhydride (MA) and diisopropanol amine (DIPA) at 140°C at a molar ratio of 1:1.3 MA: DIPA, respectively. This HBP was incorporated in the preparation of an effective microcrystalline cellulose (MCC)/dimethyloldihydroxyethylene urea (DMDHEU)/HBP adduct by crosslinking HBP with DMDHEU in presence of MCC. Furthermore, the prepared adduct was characterised by investigation its infra red and then utilised in the removal of three anionic dyestuffs from aqueous solutions, namely Irgalan Blau 3GL (an acid dye), SIRIUS Blau S‐BRR (a direct dye) and Levafix Brill Orange P‐GR (a hydrolysed reactive dye).FindingsThe results obtained revealed that the optimum conditions for preparing MCC/DMDHEU/HBP adduct are [HBP], 90 g/l; [DMDHEU], 200 g/l; LR, 1/3.3; [NC4LH], 20 g/l; a time of 30 min and a temperature of 160°C. Moreover, the results also showed that the extent of removal of such dyestuffs from their aqueous solutions by the prepared adduct follows the order: reactive dye>acid dye>direct dye, it is more pronounced at lower than at higher pH values and the removal of each dye by that adduct follows a first‐order reaction.Research limitations/implicationsOther substrates such as chitosan can be used to prepare more effective adducts.Practical implicationsHyperbranched polymers can be used effectively to prepare ion exchangers capable of removing the pollutants of dyestuffs from their aqueous solutions.Originality/valueThe aforementioned prepared HBP is a novel hyperbranched polymer and could be applied in the removal of many other pollutants.

A Glucose-Selective Fluorescent Water-Soluble Hyperbranched Polymer Sensor With Boronic Acid End Groups

We have synthesized water-soluble hyperbranched poly(p-phenylene)s having boronic acid groups capable of reacting with diol-containing saccharides. The polymerization was carried out by palladium-catalyzed Suzuki cross-coupling reaction using tribromo monomer for the preparation of hyperbranched type structure. The water-soluble hyperbranched polymer HP exhibited much higher sensitivity toward glucose compared with the linear polymer LP presumably due to the difference in the number of the boronic acids which are present in the end groups of the polymers.

Water‐proton relaxivity of hyperbranched polymers carrying TEMPO radicals

High water-soluble hyperbranched poly(styrene) (HPS) polymers carrying stable 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radicals, HPS-N-TEMPO, HPS-Im-TEMPO, and HPS-Im-(TEMPO)(2), were prepared in ca. 60% introducing yield. HPS-N-TEMPO and HPS-Im-TEMPO were determined to be nearly spherical shapes of the diameter of 2.4 +/- 0.6 and 2.2 +/- 0.6 nm, respectively, by transmission electron microscope (TEM) images. The values of water-proton relaxivity, r(1), at 25 MHz, 0.59 T, and 25 degrees C were 6.0, 5.2, and 14 mM(-1) sec(-1) for HPS-N-TEMPO, HPS-Im-TEMPO, and HPS-Im-(TEMPO)(2), respectively. The spin-lattice relaxation time (T(1))-weighted images in phantom were also observed.

Synthesis and Characterization of a Water-soluble Hyperbranched Poly(p-phenylene vinylene) (WHPV)

A water-soluble hyperbranched poly(p-phenylene vinylene)(WHPV) was synthesized through Wittig reaction. The polymer bore a -SO 3 -group in each connecting module, which makes the polymer water-soluble. The fluorescence emission band of the resulting polymer is located around 460 nm. Molecular dynamics simulation shows that the branches of the WHPV may construct many cavities and the -SO 3 -groups are located around the cavity walls. The interaction between WHPV and CdS nanoparticles should be fairly strong and the composite of WHPV with CdS nanoparticles can be obtained.

Preparation of water-soluble hyperbranched poly(sulfone-amine)s by polyaddition of N-ethylethylenediamine to divinyl sulfone

The new approach for synthesis of hyperbranched polymers from commercially available A2 and BB′2 type monomers has been further developed. Water-soluble hyperbranched poly(sulfone-amine)s with multiple amino end groups were prepared by direct polyaddition of divinyl sulfone (DV, A2) to N-ethylethylenediamine (NDA, BB′2). Effects of reaction conditions such as the feed ratio and solvents on the polymerization have been investigated. When the feed ratio of DV to NDA was equal to 1, no gelation occurred during the polymerization in water or organic solvents. Similarly, when the feed ratio of DV to AP was equal to 3/2, no insoluble or cross-linked material was observed in chloroform or other organic solvents such as N,N-dimethylforamide, N,N-dimethylacetamide and N-methyl-2-pyrrolidone. Interestingly, when water was used as solvent, the reaction mixture got turbid within 15–20min and gelation occurred within 12–15h. The turbid mixture formed during initial stage becomes a transparent solution in aqueous acid, which was coined as ‘pseudo-gelation’. The solubility of the resulting polymer in water is as high as 1.68g/ml. The degree of branching (DB) of all the resulting hyperbranched polymers is higher than 50% and the highest one is 70.9%. The reaction mechanism is presented and demonstrated with FTIR, HPLC and MS. During polymerization, secondary amino groups of NDA react rapidly with vinyl groups of DV within 12s dominantly generating dimers which can be regarded as a new AB′2 type monomer. Further polymerization of the new monomers leads to hyperbranched poly(sulfone-amine)s.