| 1. |
- Allushi, Andrit, et al.
(författare)
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Hydroxide conducting BAB triblock copolymers tailored for durable high-performance anion exchange membranes
- 2023
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Ingår i: Materials Advances. - 2633-5409. ; 4:17, s. 3733-3745
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Tidskriftsartikel (refereegranskat)abstract
- Well-designed block copolymers with a controlled co-continuous microphase morphology can be applied as efficient anion exchange membranes (AEMs) for fuel cells and water electrolyzers. In the present work, we have prepared and studied a series of BAB triblock copolymers consisting of a central cationic polyfluorene A block with flanking hydrophobic polystyrene B blocks, where the fluorene units of the A block carried double pairs of piperidinium cations via flexible hexyl spacer chains. First, a polyfluorene tethered with bromohexyl chains was prepared by superacid-mediated polyhydroxyalkylation, and then modified to produce a bi-directional macroinitiator for atom transfer radical polymerization (ATRP). Next, ATRP of styrene was carried out to form BAB triblock copolymers with different lengths of the B blocks. Finally, the polyfluorene block was densely functionalized with piperidinium cations by Menshutkin reactions. Small angle X-ray scattering of block copolymer AEMs indicated the presence of both block copolymer phase domains (d~15 nm) and ionic clusters (d~6 nm). Atomic force microscopy showed clearly phase-separated morphologies with seemingly well-connected hydrophilic nanophase domains for ion transport. The AEMs reached hydroxide conductivities up to 161 mS cm-1 at 80 ºC. Moreover, the AEMs decomposed only above 250 °C and possessed excellent alkaline stability with no degradation detected by 1H NMR analysis after storage in 2 M aq. NaOH, at 90 °C during 672 h. Notably, the current block copolymer AEMs showed higher alkaline stability and hydroxide conductivity compared to AEMs based on corresponding statistical copolymers.
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| 2. |
- Chen, Si, et al.
(författare)
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Hydroxide Conducting Membranes with Quaternary Ammonium Cations Tethered to Poly(arylene alkylene)s via Flexible Phenylpropyl Spacers
- 2024
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Ingår i: Chemistry of Materials. - 0897-4756. ; 36:1, s. 371-381
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Tidskriftsartikel (refereegranskat)abstract
- Durable and high-performing anion exchange membranes (AEMs) are central components in alkaline water electrolyzers and fuel cells. Here, we have pursued a synthetic strategy where heteroatom-free polymer backbones are functionalized with alkali-stable dimethyl piperidinium (DMP) cations via flexible spacers. We achieved this design by synthesizing a trifluorobenzophenone monomer carrying a piperidine group in the 4-position via a straightforward Friedel–Crafts acylation of 4-(3-phenylpropyl)piperidine. Polyhydroxyalkylation of this ketone and p-terphenyl, followed by N-methylation, generated a DMP-functionalized poly(p-terphenyl alkylene) (PpT-DMP) with excellent alkaline stability, e.g., less than 7% ionic loss after treatment in 7 M aq. NaOH solution at 90 °C for 240 h. A high OH– conductivity, up to 104 mS cm–1 at 80 °C, was reached at an ion exchange capacity (IEC) of 1.79 mequiv g–1 and 53% water uptake. Atomic force microscopy (AFM) revealed a distinct microphase separation into ionic and nonionic nano-domains. The Friedel–Crafts acylation method proved very versatile and was also employed to synthesize a bromoalkylated trifluorobenzophenone monomer from 1-bromo-3-phenylpropane, which gives access to a diverse range of AEM materials. Poly(arylene alkylene)s based on this monomer and p-terphenyl and dimethylfluorene, respectively, were prepared in polyhydroxyalkylation and subsequently functionalized with alkyltrimethylammonium and N-methyl-N-alkyl piperidinium cations, respectively. Especially, AEMs based on the former material showed a remarkably high conductivity, up to 175 mS cm–1 at 80 °C. In summary, we present a straightforward approach to synthesize trifluorobenzophenone monomers substituted with 4-propylpiperidine and propyl bromide groups, respectively, which enables the preparation of various heteroatom-free poly(arylene alkylene)s tethered with alkali-stable cations for high-performance AEMs.
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| 3. |
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| 4. |
- Gong, Haiyue, et al.
(författare)
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Ag−Polymer nanocomposites for capture, detection, and destruction of bacteria
- 2019
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Ingår i: ACS Applied Nano Materials. - : American Chemical Society (ACS). - 2574-0970. ; 2, s. 1655-1663
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Tidskriftsartikel (refereegranskat)abstract
- Bacterial infection is one of the major problems for human health. To prevent outbreak of bacteria-caused diseases, early diagnosis of bacterial pathogen and effective destruction of pathogenic microorganisms are in urgent need. In this work, we developed a new multifunctional nanocomposite material that can effectively capture and destroy bacteria. Epoxide-modified nanoparticles were synthesized by microemulsion polymerization and precipitation polymerization. The epoxide groups on the particle surface were reacted with polyethylenimine to introduce cationic amine groups. The amine groups on the nanoparticle surface enhanced the colloidal stability of the particles’ suspension and provided multivalent interactions to bind and destroy the bacteria. After further modification with Ag nanoparticles, the final composite nanomaterial was able to not only capture and destroy Gram-negative bacteria but also allow the bacteria’s fingerprint spectra to be obtained through surface-enhanced Raman scattering.The multifunctional nanoparticles developed in this work offer a new approach toward fast capture, detection, and destruction of pathogenic bacteria.
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| 5. |
- Gong, Haiyue, et al.
(författare)
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Boronic Acid Modified Polymer Nanoparticles for Enhanced Bacterial Deactivation
- 2019
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Ingår i: ChemBioChem. - : Wiley. - 1439-4227 .- 1439-7633. ; 20:24, s. 2991-2995
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Tidskriftsartikel (refereegranskat)abstract
- A new method has been developed to enhance the antibacterial efficiency of traditional antibiotics. Chloramphenicol‐imprinted polymer particles were decorated with boronic acid to improve their binding to both Gram‐negative and ‐positive bacteria. The polymer particles have a high antibiotic loading and provide a slow release of the antibiotic payload to deactivate the target bacteria. The boronic acid modified polymer particles not only contribute to enhanced antibacterial efficiency, but also have the potential to act as scavengers to remove unused antibiotic from the environment.
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| 6. |
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| 7. |
- Gong, Haiyue, et al.
(författare)
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Dynamic assembly of molecularly imprinted polymer nanoparticles
- 2018
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797. ; 509, s. 463-471
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Tidskriftsartikel (refereegranskat)abstract
- Manipulation of specific binding and recycling of materials are two important aspects for practical applications of molecularly imprinted polymers. In this work, we developed a new approach to control the dynamic assembly of molecularly imprinted nanoparticles by surface functionalization. Molecularly imprinted polymer nanoparticles with a well-controlled core-shell structure were synthesized using precipitation polymerization. The specific binding sites were created in the core during the first step imprinting reaction. In the second polymerization step, epoxide groups were introduced into the particle shell to act as an intermediate linker to immobilize phenylboronic acids, as well as to introduce cis-diol structures on surface. The imprinted polymer nanoparticles modified with boronic acid and cis-diol structures maintained high molecular binding specificity, and the nanoparticles could be induced to form dynamic particle aggregation that responded to pH variation and chemical stimuli. The possibility of modulating molecular binding and nanoparticle assembly in a mutually independent fashion can be exploited in a number of applications where repeated use of precious nanoparticles is needed.
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| 8. |
- Gong, Haiyue, et al.
(författare)
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Imprinted Polymer Beads Loaded with Silver Nanoparticles for Antibacterial Applications
- 2021
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Ingår i: ACS Applied Bio Materials. - : American Chemical Society (ACS). - 2576-6422. ; 4:3, s. 2829-2838
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Tidskriftsartikel (refereegranskat)abstract
- After the emergence of multidrug-resistant strains, antibiotic resistance in bacteria has become an important problem. Thus, materials for combating multidrug-resistant bacteria are of vital importance. In this work, we developed an antibacterial material that can selectively capture and destruct bacteria on the basis of their physical characteristics. To achieve bacterial capture and deactivation with a single material, we used bacterial cells as templates to synthesize surface-imprinted polymer beads in bacteria-stabilized Pickering emulsions. Acrylate-functionalized polyethylenimine was used to coat the bacterial surface so that the coated bacteria can act as a particle stabilizer to establish an oil-in-water Pickering emulsion. Hydrophobic Ag nanoparticles were introduced into the oil phase composed of cross-linking monomers. Bacteria-imprinted beads (BIB) were obtained after the oil phase was polymerized. Bacterial binding experiments confirmed the importance of the imprinted sites for specific recognition with the target bacteria. The Ag nanoparticles embedded inside the polymer beads enhanced bacterial inactivation and reduced the leakage of heavy metal in aquatic environment. The combination of bacteria-imprinting with delivery of general-purpose antibacterial reagents offers a useful approach toward selective capture and destruction of bacteria.
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| 9. |
- Gong, Haiyue
(författare)
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Multifunctional Polymer Materials: From Synthesis to Disinfection
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Polymer materials have wide applications in many industries, such as the food, pharmacy, construction, textile, and cosmetics industries. For the past few years, polymer materials have drawn the attention of scientists and engineers as a good disinfectant due to their advanced manufacturing methods, large surface areas, good stability, and lowcost. More importantly, polymer materials can be functionalized with various chemical groups to increase their affinity towards microorganisms and broaden their applications. In this thesis, four types of multifunctional polymer materials were synthesized to investigate their disinfection ability on bacterial cells.By using molecular imprinting technology, a small molecule-chloramphenicol-imprinted polymer material of nanometer size was prepared via precipitation polymerization, and large bacteria-imprinted polymer materials of micrometer size were synthesized via surface imprinting-Pickering emulsion polymerization. Both materials had highly specific binding to the targeted template and could be used as adsorbents. In precipitation polymerization, 3-(acrylamido)phenylboronic acid was added to introduce boronic acid on the material surface. In neutral and basic aqueous solutions, boronic acid groups formed reversible boronate ester bonds with the cis-diol groups of the polysaccharides on bacterial surfaces. The release of chloramphenicol led to a high antibiotic concentration around the bacterial cells, which killed the cells. In Pickering emulsion polymerization, positively charged vinyl-functionalized polyethylenimine self-assembled with negatively charged bacterial cells and acted as a stabilizer for the emulsion. Therefore, bacteria-recognition sites based on the bacteria’s physical property formed on the surface of polymer beads after crosslinking polymerization. Ag+ was released from the preloaded hydrophobic Ag nanoparticles in the polymer beads to deactivate the bound bacterial cells.To realize multifunctional materials for antibacterial applications, nanometer sized polymer materials were prepared with glycidyl methacrylate by precipitation polymerization and microemulsion polymerization. The epoxide groups were opened by polyethylenimine, which was further used to stabilize Ag nanoparticles. The final material selfassembled with bacterial cells via electrostatic interactions. The amino groups and Ag nanoparticles endowed the composite material with disinfection ability. The molecular spectra of bacteria could also be acquired via surfaceenhanced Raman scattering from the surface Ag nanoparticles.In addition to spherical polymer materials, temperature tunable deactivation polymers were also synthesized with (methacryloyloxy)ethyl]trimethylammonium by atom transfer radical polymerization, which was initiated by an initiator containing a boronic acid group. By further modification of the terminal alkyl bromide, a fluorescent molecule,fluorescein 5(6)-isothiocyanate, was added to the polymer chain. The obtained polymers self-assembled with bacterial cells via reversible boronate ester bonds and electrostatic interactions. At 40 ℃, the polymers showed effective deactivation of bacterial cells via a synergistic effect. At 20 ℃, the polymers displayed lower or no toxicityto bacterial cells and could be used to label bacterial cells in flow cytometry and fluorescence imaging.
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