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1.
Polymers (Basel) ; 15(22)2023 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-38006171

RESUMO

Vinyl-addition polynorbornenes are of great interest as versatile templates for the targeted design of polymer materials with desired properties. These polymers possess rigid and saturated backbones, which provide them with high thermal and chemical stability as well as high glass transition temperatures. Vinyl-addition polymers from norbornenes with bromoalkyl groups are widely used as precursors of anion exchange membranes; however, high-molecular-weight homopolymers from such monomers are often difficult to prepare. Herein, we report the systematic study of vinyl-addition polymerization of norbornenes with various bromoalkyl groups on Pd-catalysts bearing N-heterocyclic carbene ligands ((NHC)Pd-systems). Norbornenes with different lengths of hydrocarbon linker (one, two, and four CH2 groups) between the bicyclic norbornene moiety and the bromine atom were used as model monomers, while single- and three-component (NHC)Pd-systems were applied as catalysts. In vinyl-addition polymerization, the reactivity of the investigated monomers varied substantially. The relative reactivity of these monomers was assessed in copolymerization experiments, which showed that the closer the bromine is to the norbornene double-bond, the lower the monomer's reactivity. The most reactive monomer was the norbornene derivative with the largest substituent (with the longest linker). Tuning the catalyst's nature and the conditions of polymerization, we succeeded in synthesizing high-molecular-weight homopolymers from norbornenes with bromoalkyl groups (Mn up to 1.4 × 106). The basic physico-chemical properties of the prepared polymers were studied and considered together with the results of vinyl-addition polymerization.

2.
Angew Chem Int Ed Engl ; 62(30): e202304778, 2023 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-37141462

RESUMO

The limited number of methods to directly polymerize ionic monomers currently hinders rapid diversification and production of ionic polymeric materials, namely anion exchange membranes (AEMs) which are essential components in emerging alkaline fuel cell and electrolyzer technologies. Herein, we report a direct coordination-insertion polymerization of cationic monomers, providing the first direct synthesis of aliphatic polymers with high ion incorporations and allowing facile access to a broad range of materials. We demonstrate the utility of this method by rapidly generating a library of solution processable ionic polymers for use as AEMs. We investigate these materials to study the influence of cation identity on hydroxide conductivity and stability. We found that AEMs with piperidinium cations exhibited the highest performance, with high alkaline stability, hydroxide conductivity of 87 mS cm-1 at 80 °C, and a peak power density of 730 mW cm-2 when integrated into a fuel cell device.

3.
Polymers (Basel) ; 15(5)2023 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-36904314

RESUMO

To investigate the effect of perfluorinated substituent on the properties of anion exchange membranes (AEMs), cross-linked polynorbornene-based AEMs with perfluorinated branch chains were prepared via ring opening metathesis polymerization, subsequent crosslinking reaction, and quaternization. The crosslinking structure enables the resultant AEMs (CFnB) to exhibit a low swelling ratio, high toughness, and high water uptake, simultaneously. In addition, benefiting from the ion gathering and side chain microphase separation caused by their flexible backbone and perfluorinated branch chain, these AEMs had high hydroxide conductivity up to 106.9 mS cm-1 at 80 °C even at low ion content (IEC < 1.6 meq g-1). This work provides a new approach to achieve improved ion conductivity at low ion content by introducing the perfluorinated branch chains and puts forward a referable way to prepare AEMs with high performance.

4.
Talanta ; 258: 124473, 2023 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-36989616

RESUMO

Developing efficient photosensitizers which are sensitive to therapeutic tumor signals, but non-toxic to normal cells has always been a tremendous challenge in photodynamic therapy (PDT) process. Herein, a novel copolymer P1 was developed by ring-opening metathesis polymerization (ROMP) with disulfide bond linked ferrocene-norbornene dyad NB-SS-PyFc and the aggregation-induced emission (AIE) fluorephore anchored norbornene NB-TPE, and its nanoparticles (NPs) were obtained by using the amphiphilic Pluronic F-127 as the surfactant via a nanoprecipitation method. The P1 NPs show a weak emission and a low 1O2 generation for the quenching effect from the ferrocene moiety to the AIE group. However, the addition of GSH can recover the AIE fluorephore emission and 1O2 generation for cleavage the disulfide bond. Importantly, P1 NPs have been used for image-guided cancer cells apoptosis for the GSH activated 1O2 generation.


Assuntos
Nanopartículas , Neoplasias , Fotoquimioterapia , Humanos , Sulfetos/química , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacologia , Polímeros/química , Polímeros/farmacologia , Metalocenos/química
5.
Polymers (Basel) ; 14(24)2022 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-36559820

RESUMO

Optically active polymers are of great interest as materials for dense enantioselective membranes, as well as chiral stationary phases for gas and liquid chromatography. Combining the versatility of norbornene chemistry and the advantages of chiral natural terpenes in one molecule will open up a facile route toward the synthesis of diverse optically active polymers. Herein, we prepared a set of new chiral monomers from cis-5-norbornene-2,3-dicarboxylic anhydride and chiral alcohols of various natures. Alcohols based on cyclic terpenes ((-)-menthol, (-)-borneol and pinanol), as well as commercially available alcohols (S-(-)-2-methylbutanol-1, S-(+)-3-octanol), were used. All the synthesized monomers were successfully involved in ring-opening metathesis polymerization, affording polymers in high yields (up to 96%) and with molecular weights in the range of 1.9 × 105-5.8 × 105 (Mw). The properties of the metathesis polymers obtained were studied by TGA and DSC analysis, WAXD, and circular dichroism spectroscopy. The polymers exhibited high thermal stability and good film-forming properties. Glass transition temperatures for the prepared polymers varied from -30 °C to +139 °C and, therefore, the state of the polymers changed from rubbery to glassy. The prepared polymers represent a new attractive platform of chiral polymeric materials for enantioselective membrane separation and chiral stationary phases for chromatography.

6.
Polymers (Basel) ; 14(12)2022 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-35745918

RESUMO

The contamination of water resources with heavy metals is a very serious concern that demands prompt and effective attention due to the serious health risks caused by these contaminants. The synthesis and ring-opening metathesis polymerization (ROMP) of norbornene dicarboximides bearing thiol pendant groups, specifically, N-4-thiophenyl-exo-norbornene-5,6-dicarboximide (1a), N-4-(methylthio)phenyl-exo-norbornene-5,6-dicarboximide (1b) and N-4-(trifluoromethylthio)phenyl-exo-norbornene-5,6-dicarboximide (1c), as well as their assessment for the removal of heavy metals from aqueous systems, is addressed in this work. The polymers were characterized by NMR, SEM and TGA, among others. Single and multicomponent aqueous solutions of Pb2+, Cd2+ and Ni2+ were employed to perform both kinetic and isothermal adsorption studies taking into account several experimental parameters, for instance, the initial metal concentration, the contact time and the mass of the polymer. In general, the adsorption kinetic data fit the pseudo-second-order model more efficiently, while the adsorption isotherms fit the Freundlich and Langmuir models. The maximum metal uptakes were 53.7 mg/g for Pb2+, 43.8 mg/g for Cd2+ and 29.1 mg/g for Ni2+ in the SH-bearing polymer 2a, 46.4 mg/g for Pb2+, 32.9 mg/g for Cd2+ and 27.1 mg/g for Ni2+ in the SCH3-bearing polymer 2b and 40.3 mg/g for Pb2+, 35.9 mg/g for Cd2+ and 27.8 mg/g for Ni2+ in the SCF3-bearing polymer 2c, correspondingly. The better performance of polymer 2a for the metal uptake was ascribed to the lower steric hindrance and higher hydrophilicity imparted by -SH groups to the polymer. The results show that these thiol-functionalized polymers are effective adsorbents of heavy metal ions from aqueous media.

7.
Polymers (Basel) ; 14(3)2022 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-35160434

RESUMO

Commercial metathesis polynorbornene is used for the fabrication of high-damping coatings and bulk materials that dissipate vibration and impact energies. Functionalization of this non-polar polymer can improve its adhesive, gas barrier, and other properties, thereby potentially expanding its application area. With this aim, the post-modification of polynorbornene was carried out by inserting ethylene-vinyl acetate-vinyl alcohol blocks into its backbone via the cross-metathesis of polynorbornene with poly(5-acetoxy-1-octenylene) and subsequent deacetylation and hydrogenation of the obtained multiblock copolymers. For the first time, epoxy groups were introduced into the main chains of these copolymers, followed by the oxirane ring opening reaction. The influence of post-modification on the thermal, gas separation, and mechanical properties of the new copolymers was studied. It was shown that the gas permeability of the copolymer significantly depends on its composition, as well as on the amounts of hydroxyl and epoxy groups. The developed methods efficiently improve the barrier properties, reducing the oxygen permeability by 15-33 times in comparison with polynorbornene. The obtained results are promising for various applications and can be extended to a broader family of polydienes and other polymers containing backbone double bonds.

8.
Spectrochim Acta A Mol Biomol Spectrosc ; 269: 120771, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34952445

RESUMO

A novel aminoquinoline functionalized norbornene (1) and its ring-opening metathesis polymerization (ROMP) copolymer P1 have been designed and synthesized. The polymer probe P1 can self-assemble nano aggregation in aqueous solution. The fluorescent experiments revealed that both 1 and P1 show a ratiometric fluorescence response toward Zn2+ over other mental ions in Tris-HCl buffer solution, with the polymer probe P1 shows a better photostability and higher binding affinity than that of the small molecular probe 1. Furthermore, the in situ formed P1-Zn2+ ensemble was successfully used as the secondary sensor for ATP. P1 is also successfully used for monitoring intracellular Zn2+ and ATP in living cells.


Assuntos
Corantes Fluorescentes , Zinco , Trifosfato de Adenosina , Aminoquinolinas , Plásticos
9.
Materials (Basel) ; 14(12)2021 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-34204638

RESUMO

In this work, tetrakis(dimethyllamino)ethylene (TDAE) plasticized polynorbornene (PNB) was used as the matrix, sulfur (S) and dicumyl peroxide (DCP) were simultaneously used as crosslinking agents to construct dual covalent cross-linking networks in PNB. The effects of different amounts of cross-linkers on the crosslinking degree, mechanical property, glass transition temperature, and PNB shape memory performance were investigated. Two crosslinking mechanisms were examined by Fourier transform infrared spectrometer and Raman spectrometer. The results showed that sulfur-rich cross-linked PNB exhibited a higher crosslinking degree, tensile strength, and slightly higher glass transition temperature than the DCP-rich system. Cross-linked PNB presented better shape memory performance than the uncross-linked one. Sulfur-rich cross-linked PNB showed even better shape memory behavior than the DCP-rich system, both with a shape fixation ratio of over 99% and a shape recovery ratio of over 90%. The reaction mechanism of sulfur and DCP in cross-linking PNB was different. Sulfur reacted with the α-H in PNB to form monosulfide bonds, disulfide bonds, and polysulfide bonds in PNB and the number of polysulfide bonds increased with increased amounts of sulfur. DCP reacted with the double bonds in PNB to form C-C covalent bond crosslinking networks. The crosslinking mechanism revealed that the sulfur-containing cross-linked bonds, especially polysulfide bonds, were more flexible and bore large deformation, which gave the PNB excellent mechanical properties and ensured a higher shape entropy elastic recovery ratio.

10.
Environ Sci Pollut Res Int ; 28(37): 52014-52031, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33997932

RESUMO

The occurrence of heavy metals in the natural aquatic systems arising from anthropogenic sources is an issue of global and environmental concern because of their extremely harmful effects to living beings even in rather low concentrations. The synthesis and ring-opening metathesis polymerization (ROMP) of novel norbornene dicarboximides bearing highly aromatic pendant groups, specifically, N-4-tritylphenyl-norbornene-5,6-dicarboximide (2a) and N-2,4,6-(triphenyl)phenyl-norbornene-5,6-dicarboximide (2b), their hydrogenation and further polymer sulfonation to render them adsorbents for the uptake of heavy metal ions from water is reported in this study. The macromolecules were characterized by means of FT-IR, 1H NMR, and thermal analysis, among others. A thoroughly kinetic and isothermal study of adsorption in single and ternary aqueous solutions of Pb2+, Cd2+, and Ni2+ was performed considering several experimental variables for instance initial metal concentration, contact time and solution pH. In general, the experimental data were adjusted more efficiently to the pseudo-second order kinetic model and to the Freundlich isotherm model, respectively. The maximum removal amounts were found to be 55.7 mg/g for Pb2+, 33.9 mg/g for Cd2+, and 10.2 mg/g for Ni2+ in the sulfonated trityl-bearing polymer 5a while those found for the sulfonated triphenyl-bearing polymer 5b were 31.5 mg/g for Pb2+, 26.6 mg/g for Cd2+, and 7.0 mg/g for Ni2+, respectively. The higher heavy metal removal capacity of polymer 5a was attributed to its also higher degree of sulfonation. The outcomes indicate that these novel sulfonic acid containing polymer-based adsorbents are effective for the uptake of heavy metallic elements from water.


Assuntos
Metais Pesados , Poluentes Químicos da Água , Adsorção , Cádmio/análise , Concentração de Íons de Hidrogênio , Cinética , Plásticos , Espectroscopia de Infravermelho com Transformada de Fourier , Água , Poluentes Químicos da Água/análise
11.
Des Monomers Polym ; 23(1): 141-154, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-33029082

RESUMO

Polynorbornenes, prepared by the 'living' and 'controlled' ring-opening metathesis polymerization (ROMP) method, have emerged as a stimuli-sensitive new class of polymer carriers. Herein, we reported a novel amphiphilic diblock polynorbornene, PNCHO-b-PNTEG, containing active benzaldehyde units, which exhibited good conjugating capacity to amino-containing molecules (e.g., doxorubicin (DOX)) via the pH-sensitive Schiff base linkage. The copolymer and its conjugate with DOX, DOX-PNCHO-b-PNTEG, were adequately analyzed by various techniques including 1H NMR, 13C NMR, gel permeation chromatography, etc. Especially, the formed conjugate of DOX-PNCHO-b-PNTEG could self-assemble into near-spherical micelles with the diameter of 81 ± 10 nm, and exhibit acid-triggered DOX release behavior, and the release rate could be adjusted by changing the environmental pH value. The excellent biological safety of PNCHO-b-PNTEG was further demonstrated by the results from both in vitro toxicity evaluation to murine fibroblast cells (L-929 cells) and in vivo evaluation of acute developmental toxicity and cell death in zebrafish embryos. Hence, the present polynorbornene-based PNCHO-b-PNTEG possesses great potential application as a biocompatible polymeric carrier and could be employed to fabricate various pH-sensitive conjugates.

12.
Angew Chem Int Ed Engl ; 59(45): 20174-20182, 2020 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-32696572

RESUMO

Through-space charge transfer polynorbornenes with fixed and controllable spatial alignment of donor and acceptor in edge-to-face/face-to-face stacking patterns are developed for achieving high-efficiency blue thermally activated delayed fluorescence (TADF). The alignment is realized by using the cis, exo-configuration of norbornene to confine donor and acceptor in close proximity, and utilizing orthogonal and dendritic structures of donors to provide either perpendicular or parallel stacking motif relative to acceptors. Compared to edge-to-face counterparts, polynorbornenes with face-to-face aligned donor and acceptor exhibit much larger oscillator strength and higher photoluminescence quantum yield. The resulting polymers exhibit deep blue (422 nm) to sky blue (482 nm) emission and TADF effect with reverse intersystem crossing rates of 0.4-5.9×106  s-1 , giving the maximum external quantum efficiency of 18.8 % for non-doped blue organic light-emitting diodes by solution process.

13.
Macromol Rapid Commun ; 41(4): e1900598, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31880033

RESUMO

An efficient bimolecular ring-closure method is developed to prepare the well-defined cyclic polynorbornenes by combining the living ring-opening metathesis polymerization (ROMP) with the self-accelerating double strain-promoted azide-alkyne cycloaddition (DSPAAC) reaction. In this method, ROMP is used to synthesize the well-defined linear polynorbornenes with both azide terminals by virtue of a N-hydroxysuccinimide-ester-functionalized Grubbs initiator following the modification of polymer end groups. DSPAAC click reaction is then used to ring-close the linear polymer precursors and prepare the corresponding well-defined cyclic polynorbornenes using the sym-dibenzo-1,5-cyclooctadiene-3,7-diyne (DIBOD) as small linkers. The self-accelerating DSPAAC ring-closing reaction facilitates this method to efficiently prepare pure cyclic polynorbornenes in the presence of a molar excess of DIBOD small linkers to the linear polynorbornene precursors. This is the first report to prepare well-defined polynorbornenes with cyclic topology based on the ring-closure strategy for cyclic polymers.


Assuntos
Reação de Cicloadição/métodos , Plásticos/síntese química , Polímeros/síntese química , Alcinos/química , Azidas/química , Química Click , Plásticos/análise , Plásticos/química , Polimerização , Polímeros/química
14.
Polymers (Basel) ; 11(2)2019 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-30960282

RESUMO

In this review, molecular brushes and other macromolecular architectures bearing a bottlebrush segment where the main chain is synthesized by ring opening metathesis polymerization (ROMP) mediated by Mo or Ru metal complexes are considered. A brief review of metathesis and ROMP is presented in order to understand the problems and the solutions provided through the years. The synthetic strategies towards bottlebrush copolymers are demonstrated and each one discussed separately. The initiators/catalysts for the synthesis of the backbone with ROMP are discussed. Syntheses of molecular brushes are presented. The most interesting properties of the bottlebrushes are detailed. Finally, the applications studied by different groups are presented.

15.
Polymers (Basel) ; 11(4)2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30999614

RESUMO

Polynorbornenes are already used in a wide range of applications. They are also considered materials for polymer gas separation membranes because of their favorable thermal and chemical resistance, rigid backbone and varied chemistry. In this study, the use of 5-vinyl-2-norbornene (VNB), a new monomer in the field of gas separations, is investigated by synthesizing two series of polymers via a vinyl-addition polymerization. The first series investigates the influence of the VNB content on gas separation in a series of homo and copolymers with norbornene. The second series explores the influence of the crosslinking of polyvinylnorbornene (pVNB) on gas separation. The results indicate that while crosslinking had little effect, the gas separation performance could be fine-tuned by controlling the VNB content. As such, this work demonstrates an interesting way to significantly extend the fine-tuning possibilities of polynorbornenes for gas separations.

16.
ACS Appl Bio Mater ; 1(3): 613-626, 2018 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-34405136

RESUMO

A poly(oxanorbornene)-based polyzwitterion with primary ammonium and carboxylate groups (PZI) has been reported previously as the first simultaneously antimicrobial and protein-repellent polyzwitterion. Here, additional physical and biological properties of three poly(oxanorbornene)-based polyzwitterions with different functional groups (PZI, the polycarboxybetaine PCB, and the polysulfobetaine PSB) are compared to understand the molecular origins of this unusual bioactivity. Additionally, the three polyzwitterions and the antimicrobial, polycationic SMAMP are exposed to proteins, bacteria suspensions, human plasma and serum. These interactions are investigated by surface plasmon resonance spectroscopy. In protein adhesion studies, neither fibrinogen nor lysozyme adhere irreversibly to PZI, yet reversible interaction with lysozyme is observed at pH 7 and 8. In the presence of bivalent cations, reversible fibrinogen adhesion on PZI and PSB is observed, but not on PCB. This might explain why mammalian cells grow on PZI and PSB, but not on PCB. PZI does not show human plasma adhesion, while PCB and PSB have 0.27 and 0.48 ng mm-2 adhered plasma, and SMAMP even 6.3 ng mm-2. Both PZI and SMAMP show strong serum adhesion, while no serum adhered to PCB, and only little to PSB. This could be related to the pH difference between serum and plasma, to which the pH-responsive primary ammonium groups are susceptible, while the permanently charged NR4 + groups are unaffected. Both PZI and PCB showed none or only little bacterial adhesion. PCB is also intrinsically antimicrobial against E. coli and S. aureus bacteria and thus is also simultaneously protein-repellent and antimicrobially active. Thus, while the carboxylate groups of PZI and PCB seems to be a prerequisite for the dual antimicrobial activity and protein-repellency, the pH-responsiveness of the primary ammonium group seems to make the PZI molecule vulnerable for protein adhesion in fluids that are slightly out of the physiological range.

17.
J Colloid Interface Sci ; 510: 86-94, 2018 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-28942068

RESUMO

HYPOTHESIS: In situ crosslinking is expected to increase the solvent stability of coatings formed by surface-initiated ring opening metathesis polymerization (SI ROMP). Solvent-associated degradation limits the utility of SI ROMP coatings. SI ROMP coatings have a unique capacity for post-functionalization through reaction of the unsaturated site on the polymer backbone. Any post-reaction scheme which requires a liquid solvent has the potential to degrade the coating and lower the thickness of the resulting film. EXPERIMENTS: We designed a macromolecular crosslinking group based on PEG dinorbornene. The PEG length is tailored to the expected mean chain to chain distance during surface-initiated polymerization. This crosslinking macromer is randomly copolymerized with norbornene through SI ROMP on a gold coated substrate. The solvent stability of polynorbornene coatings with and without PEG dinorbornene is quantitatively determined, and the mechanism of degradation is further supported through XPS and AFM analyses. FINDINGS: The addition of the 0.25mol% PEG dinorbornene significantly increases the solvent stability of the SI ROMP coatings. The crosslinker presence in the more stable films is supported with observable PEG absorbances by FTIR and an increase in contact angle hysteresis when compared to non-crosslinked coatings. The oxidation of the SI ROMP coatings is supported by the observation of carbonyl oxygen in the polynorbornene coatings. The rapid loss of the non-crosslinked SI ROMP coating corresponds to nanoscale pitting across the surface and micron-scale regions of widespread film loss. The crosslinked coatings have uniform nanoscale pitting, but the crosslinked films show no evidence of micron-scale film damage. In all, the incorporation of minimal crosslinking content is a simple strategy for improving the solvent stability of SI ROMP coatings.

18.
Mol Pharm ; 14(7): 2378-2389, 2017 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-28605595

RESUMO

The novel self-assembling bottlebrush polyethylene glycol-polynorbornene-thiocresol block copolymers (PEG-PNB-TC) were synthesized by the ring opening metathesis polymerization (ROMP), followed by functionalization of the polymer backbone via the thio-bromo "click" postpolymerization strategy. The PEG-PNB-TC copolymers could easily self-assemble into the nanoscale core-shell polymeric micelles. The hydrophobic anticancer drugs, such as paclitaxel (PTX), could be loaded into their hydrophobic core to form a stable drug-loaded micelle with a superior drug loading capacity of up to ∼35% (w/w). The sustained drug release behavior of the PEG-PNB-TC micelles was observed under a simulated "sink condition". Compared with commercial PTX formulation (Taxol), the PTX-loaded PEG-PNB-TC micelles showed the enhanced in vitro cellular uptake and comparable cytotoxicity in the drug-sensitive cancer cells, while the copolymers were much safer than Cremophor EL, the surfactant used in Taxol. Furthermore, curcumin (CUR), a natural chemotherapy drug sensitizer, was successfully coloaded with PTX into the PEG-PNB-TC micelles. High drug loading capacity of the PEG-PNB-TC micelles allowed for easy adjustment of drug doses and the ratio of the coloaded drugs. The combination of PTX and CUR showed synergistic anticancer effect in both the drug mixture and drug coloaded micelles at high CUR/PTX ratio, while low CRU/PTX ratio only exhibited additive effects. The combinatorial effects remarkably circumvented the PTX resistance in the multidrug resistant (MDR) cancer cells. Due to the easy polymerization and functionalization, excellent self-assembly capability, high drug loading capability, and great stability, the PEG-PNB-TC copolymers might be a promising nanomaterial for delivery of the hydrophobic anticancer drugs, especially for combination drug therapy.


Assuntos
Antineoplásicos/farmacologia , Curcumina/farmacologia , Micelas , Paclitaxel/farmacologia , Polímeros/química , Células A549 , Antineoplásicos/administração & dosagem , Cromatografia Líquida de Alta Pressão , Curcumina/administração & dosagem , Células HeLa , Humanos , Paclitaxel/administração & dosagem , Plásticos/química
19.
Adv Mater ; 29(12)2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28117506

RESUMO

A thermoplastic high strain multishape memory polymer can be fabricated using a hemiphasmid side-chain polynorbornene (P1) with hexagonal columnar liquid crystalline (ΦH ) phase. Without any chemical crosslinks, P1 can memorize multiple temporary shapes with high strain and exhibit excellent shape fixity and shape recovery. As the building blocks of ΦH , the multichain columns in P1 act as robust physical crosslinks.

20.
Polymers (Basel) ; 9(11)2017 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-30965934

RESUMO

A new class of thermochromic polynorbornene with pendent spiropyran moieties has been synthesized. Functionalization of norbornene monomers with spirobenzopyran moieties has been achieved using Steglich esterification. These new monomeric materials were polymerized via Ring Opening Metathesis Polymerization (ROMP). In spite of their poor solubility, polynorbornenes with spirobenzopyran exhibited thermochromic behavior due to the conversion of their closed spiropyran moieties to the open merocyanine form. Moreover, these polymers displayed bathochromic shifts in their optical response, which was attributed to the J-aggregation of the attached merocyanine moieties that were associated with their high concentration in the polymeric chain. The surface of the obtained polymers was exposed to atmospheric pressure air Dielectric Barrier Discharge (DBD) plasma system, which resulted in the reduction of the surface porosity and converted some surface area into completely non-porous regions. Moreover, the plasma system created some areas with highly ordered J-aggregates of the merocyanine form in thread-like structures. This modification of the polymers' morphology may alter their applications and allow for these materials to be potential candidates for new applications, such as non-porous membranes for reverse osmosis, nanofiltration, or molecular separation in the gas phase.

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