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1.
Nature ; 599(7884): 229-233, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34759362

RESUMO

Inspired by living organisms, soft robots are developed from intrinsically compliant materials, enabling continuous motions that mimic animal and vegetal movement1. In soft robots, the canonical hinges and bolts are replaced by elastomers assembled into actuators programmed to change shape following the application of stimuli, for example pneumatic inflation2-5. The morphing information is typically directly embedded within the shape of these actuators, whose assembly is facilitated by recent advances in rapid prototyping techniques6-11. Yet, these manufacturing processes have limitations in scalability, design flexibility and robustness. Here we demonstrate a new all-in-one methodology for the fabrication and the programming of soft machines. Instead of relying on the assembly of individual parts, our approach harnesses interfacial flows in elastomers that progressively cure to robustly produce monolithic pneumatic actuators whose shape can easily be tailored to suit applications ranging from artificial muscles to grippers. We rationalize the fluid mechanics at play in the assembly of our actuators and model their subsequent morphing. We leverage this quantitative knowledge to program these soft machines and produce complex functionalities, for example sequential motion obtained from a monotonic stimulus. We expect that the flexibility, robustness and predictive nature of our methodology will accelerate the proliferation of soft robotics by enabling the assembly of complex actuators, for example long, tortuous or vascular structures, thereby paving the way towards new functionalities stemming from geometric and material nonlinearities.


Assuntos
Robótica/instrumentação , Materiais Biomiméticos/síntese química , Materiais Biomiméticos/química , Polivinil/síntese química , Polivinil/química , Elastômeros de Silicone/síntese química , Elastômeros de Silicone/química , Siloxanas/síntese química , Siloxanas/química
2.
J Cell Mol Med ; 28(11): e18389, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38864691

RESUMO

Chemotherapy resistance remains a significant challenge in treating ovarian cancer effectively. This study addresses this issue by utilizing a dual drug-loaded nanomicelle system comprising albendazole (ABZ) and paclitaxel (PTX), encapsulated in a novel carrier matrix of D-tocopheryl polyethylene glycol 1000 succinate vitamin E (TPGS), soluplus and folic acid. Our objective was to develop and optimize this nanoparticulate delivery system using solvent evaporation techniques to enhance the therapeutic efficacy against ovarian cancer. The formulation process involved pre-formulation, formulation, optimization, and comprehensive characterization of the micelles. Optimization was conducted through a 32 factorial design, focusing on the effects of polymer ratios on particle size, zeta potential, polydispersity index (PDI) and entrapment efficiency (%EE). The optimal formulation demonstrated improved dilution stability, as indicated by a critical micelle concentration (CMC) of 0.0015 mg/mL for the TPGS-folic acid conjugate (TPGS-FOL). Extensive characterization included differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR), and Fourier-transform infrared spectroscopy (FTIR). The release profile exhibited an initial burst followed by sustained release over 90 h. The cytotoxic potential of the formulated micelles was superior to that of the drugs alone, as assessed by MTT assays on SKOV3 ovarian cell lines. Additionally, in vivo studies confirmed the presence of both drugs in plasma and tumour tissues, suggesting effective targeting and penetration. In conclusion, the developed TPGS-Fol-based nanomicelles for co-delivering ABZ and PTX show promising results in overcoming drug resistance, enhancing solubility, sustaining drug release, and improving therapeutic outcomes in ovarian cancer treatment.


Assuntos
Albendazol , Micelas , Neoplasias Ovarianas , Paclitaxel , Feminino , Paclitaxel/farmacologia , Paclitaxel/administração & dosagem , Paclitaxel/uso terapêutico , Paclitaxel/química , Albendazol/química , Albendazol/farmacologia , Albendazol/administração & dosagem , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/patologia , Humanos , Animais , Linhagem Celular Tumoral , Portadores de Fármacos/química , Polietilenoglicóis/química , Vitamina E/química , Ácido Fólico/química , Camundongos , Liberação Controlada de Fármacos , Tamanho da Partícula , Polivinil/química , Polímeros/química , Ensaios Antitumorais Modelo de Xenoenxerto
3.
J Am Chem Soc ; 146(36): 25383-25393, 2024 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-39196894

RESUMO

The regulation of the cell membrane potential plays a crucial role in governing the transmembrane transport of various ions and cellular life processes. However, in situ and on-demand modulation of cell membrane potential for ion channel regulation is challenging. Herein, we have constructed a supramolecular assembly system based on water-soluble cationic oligo(phenylenevinylene) (OPV) and cucurbit[7]uril (CB[7]). The controllable disassembly of OPV/4CB[7] combined with the subsequent click reaction provides a step-by-step adjustable surface positive potential. These processes can be employed in situ on the plasma membrane to modulate the membrane potential on-demand for precisely controlling the activation of the transient receptor potential vanilloid 1 (TRPV1) ion channel and up-regulating exogenous calcium-responsive gene expression. Compared with typical optogenetics, electrogenetics, and mechanogenetics, our strategy provides a perspective supramolecular genetics toolbox for the regulation of membrane potential and downstream intracellular gene regulation events.


Assuntos
Imidazóis , Potenciais da Membrana , Imidazóis/química , Humanos , Hidrocarbonetos Aromáticos com Pontes/química , Polivinil/química , Membrana Celular/metabolismo , Membrana Celular/química , Canais de Cátion TRPV/metabolismo , Células HEK293 , Cálcio/metabolismo , Cálcio/química , Canais de Cálcio/metabolismo , Canais de Cálcio/química , Compostos Heterocíclicos com 2 Anéis , Compostos Macrocíclicos , Imidazolidinas
4.
Anal Chem ; 96(15): 5887-5896, 2024 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-38567874

RESUMO

Microcystin-LR (MC-LR) is a severe threat to human and animal health; thus, monitoring it in the environment is essential, especially in water quality protections. Herein, in this work, we synthesize PVDF/CNT/Ag molecular imprinted membranes (PCA-MIMs) via an innovative combination of surface-enhanced Raman spectroscopy (SERS) detection, membrane separation, and molecular-imprinted technique toward the analysis of MC-LR in water. In particular, a light-initiated imprint is employed to protect the chemical structure of the MC-LR molecules. Furthermore, in order to ensure the detection sensitivity, the SERS substrates are combined with the membrane via the assistance of magnetism. The effect of synthesis conditions on the SERS sensitivity was investigated in detail. It is demonstrated from the characteristic results that the PCA-MIMs present high sensitivity to the MC-LR molecules with excellent selectivity against the interfere molecules. Results clearly show that the as-prepared PCA-MIMs hold great potential applications to detect trace MC-LR for the protection of water quality.


Assuntos
Biomimética , Polímeros de Fluorcarboneto , Polivinil , Análise Espectral Raman , Humanos , Análise Espectral Raman/métodos , Microcistinas/análise , Toxinas Marinhas
5.
Electrophoresis ; 45(15-16): 1443-1449, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38234009

RESUMO

The main goal of the work was to find biochemical protein markers specific for grapes and wine in ancient amphorae shards and fermentation pools. Grape-specific proteins are more reliable markers than tartaric acid and other small organic acids (tartaric acid natural source are not only grape but also apple, mango, and other plants). The Yavne winery (located in the Central District of Israel) is stated to be the largest known wine production complex from the Byzantine period (ca. 1500 years ago). The site has been excavated recently, and a number of wine jar have been recovered. We have applied our ethylene vinyl acetate (EVA) (EVA studded with strong cation and anion exchangers) diskettes to the inner surface of a number of jars, thus capturing residual grape proteins therein. Via mass spectrometry analyses, we have been able to identify four grape and three yeast proteins. This has been possible because the EVA films, applied to such surfaces, are able to harvest and concentrate any trace species, rendering them amenable to instrumental analysis. Our analysis makes it possible to propose an explanation for the Holy Grail phenomenon as a dish in which wine or water begins to smell pleasant. We attribute this to the slow release of terpenes, aldehydes, and ketones from the clay walls of pottery. After digital modeling, we identified that "scallop-shaped" niches in winery were used for the condensation of high percentage alcohol by passive evaporation from fermentation tanks.


Assuntos
Argila , Proteínas de Plantas , Vitis , Vinho , Vitis/química , Vinho/análise , Argila/química , Proteínas de Plantas/análise , Silicatos de Alumínio/química , Polivinil/química
6.
Chem Res Toxicol ; 37(9): 1588-1597, 2024 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-39237351

RESUMO

Histones and their posttranslational modifications (PTMs) are critical regulators of gene expression. Differentiation, environmental stressors, xenobiotics, and major human diseases cause significant changes in histone variants and PTMs. Western blotting is the mainstay methodology for detection of histones and their PTMs in the majority of studies. Surprisingly, despite their high abundance in cells, immunoblotting of histones typically involves loading of large protein amounts that are normally used for detection of sparse cellular proteins. We systematically examined technical factors in the Western-blotting-based detection of human histones with >30 antibodies. We found that under multiple protein transfer conditions, many histone epitopes on polyvinylidene fluoride (PVDF) membranes had a very low antibody accessibility, which was dramatically increased by the addition of a simple denaturation step. Denaturation of membrane-bound proteins also enhanced the specificity of some histone antibodies. In comparison to standard PVDF membranes, the sensitivity of histone detection on standard nitrocellulose membranes was typically much higher, which was further increased by the inclusion of the same denaturation step. Optimized protocols increased by >100-times detection sensitivity for the genotoxic marker γ-H2AX with two monoclonal antibodies. The impact of denaturation and nitrocellulose use varied for different histones, but for each histone, it was generally similar for antibodies targeting N-terminal and C-terminal regions. In summary, denaturation of membrane-bound histones strongly improves their detection by Westerns, resulting in more accurate measurements and permitting analyses with small biological samples.


Assuntos
Histonas , Histonas/química , Histonas/metabolismo , Histonas/análise , Humanos , Western Blotting , Polivinil/química , Polímeros de Fluorcarboneto
7.
Biotechnol Bioeng ; 121(9): 2678-2690, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38702962

RESUMO

The growing demand for biological therapeutics has increased interest in large-volume perfusion bioreactors, but the operation and scalability of perfusion membranes remain a challenge. This study evaluates perfusion cell culture performance and monoclonal antibody (mAb) productivity at various membrane fluxes (1.5-5 LMH), utilizing polyvinylidene difluoride (PVDF), polyethersulfone (PES), or polysulfone (PS) membranes in tangential flow filtration mode. At low flux, culture with PVDF membrane maintained higher cell culture growth, permeate titer (1.06-1.34 g/L) and sieving coefficients (≥83%) but showed lower permeate volumetric throughput and higher transmembrane pressure (TMP) (>1.50 psi) in the later part of the run compared to cultures with PES and PS membrane. However, as permeate flux increased, the total mass of product decreased by around 30% for cultures with PVDF membrane, while it remained consistent with PES and PS membrane, and at the highest flux studied, PES membrane generated 12% more product than PVDF membrane. This highlights that membrane selection for large-volume perfusion bioreactors depends on the productivity and permeate flux required. Since operating large-volume perfusion bioreactors at low flux would require several cell retention devices and a complex setup, PVDF membranes are suitable for low-volume operations at low fluxes whereas PES membranes can be a desirable alternative for large-volume higher demand products at higher fluxes.


Assuntos
Anticorpos Monoclonais , Reatores Biológicos , Cricetulus , Membranas Artificiais , Anticorpos Monoclonais/química , Anticorpos Monoclonais/biossíntese , Células CHO , Animais , Técnicas de Cultura de Células/métodos , Técnicas de Cultura de Células/instrumentação , Polímeros/química , Sulfonas/química , Perfusão/métodos , Perfusão/instrumentação , Polivinil/química , Cricetinae , Polímeros de Fluorcarboneto
8.
Mol Pharm ; 21(4): 1933-1941, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38502549

RESUMO

Islatravir, a highly potent nucleoside reverse transcriptase translocation inhibitor (NRTTI) for the treatment of HIV, has great potential to be formulated as ethylene-vinyl acetate (EVA) copolymer-based implants via hot melt extrusion. The crystallinity of EVA determines its physical and rheological properties and may impact the drug-eluting implant performance. Herein, we describe the systematic analysis of factors affecting the EVA crystallinity in islatravir implants. Differential scanning calorimetry (DSC) on EVA and solid-state NMR revealed drug loading promoted EVA crystallization, whereas BaSO4 loading had negligible impact on EVA crystallinity. The sterilization through γ-irradiation appeared to significantly impact the EVA crystallinity and surface characteristics of the implants. Furthermore, DSC analysis of thin implant slices prepared with an ultramicrotome indicated that the surface layer of the implant was more crystalline than the core. These findings provide critical insights into factors affecting the crystallinity, mechanical properties, and physicochemical properties of the EVA polymer matrix of extruded islatravir implants.


Assuntos
Desoxiadenosinas , Etilenos , Polivinil , Compostos de Vinila , Polivinil/química
9.
Biomacromolecules ; 25(9): 5541-5591, 2024 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-39129463

RESUMO

The future development of wearable/implantable sensing and medical devices relies on substrates with excellent flexibility, stability, biocompatibility, and self-powered capabilities. Enhancing the energy efficiency and convenience is crucial, and converting external mechanical energy into electrical energy is a promising strategy for long-term advancement. Poly(vinylidene fluoride) (PVDF), known for its piezoelectricity, is an outstanding representative of an electroactive polymer. Ingeniously designed PVDF-based polymers have been fabricated as piezoelectric devices for various applications. Notably, the piezoelectric performance of PVDF-based platforms is determined by their structural characteristics at different scales. This Review highlights how researchers can strategically engineer structures on microscopic, mesoscopic, and macroscopic scales. We discuss advanced research on PVDF-based piezoelectric platforms with diverse structural designs in biomedical sensing, disease diagnosis, and treatment. Ultimately, we try to give perspectives for future development trends of PVDF-based piezoelectric platforms in biomedicine, providing valuable insights for further research.


Assuntos
Polivinil , Polivinil/química , Humanos , Materiais Biocompatíveis/química , Polímeros de Fluorcarboneto
10.
Biomacromolecules ; 25(9): 6060-6071, 2024 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-39172158

RESUMO

This work aims at synthesizing tailor-made poly(vinyl alcohol-co-vinyl acetate) (PVA) amphiphilic copolymers, obtained by alcoholysis of poly(vinyl acetate) (PVAc) that could display improved properties as stabilizers compared to commercially available PVAs. Well-defined PVAs with different alcoholysis degrees were produced from a library of PVAc homopolymers synthesized by macromolecular design via interchange of xanthate polymerization and exhibiting different degrees of polymerization degrees. Subsequently, these PVAs were evaluated as stabilizers in the emulsion copolymerization of VAc and vinyl neodecanoate (VERSA 10, referred to as V10) and compared to a commercially available reference PVA obtained by alcoholysis of PVAc formed by conventional radical polymerization. In all cases, stable latexes were obtained and compared in terms of their colloidal characteristics. To identify the best stabilizer candidate, the amount of PVA remaining in water and not participating to the particle stabilization was evaluated in each case.


Assuntos
Emulsões , Polimerização , Álcool de Polivinil , Compostos de Vinila , Emulsões/química , Compostos de Vinila/química , Álcool de Polivinil/química , Polivinil/química , Polivinil/síntese química , Polímeros/química , Polímeros/síntese química
11.
Biomacromolecules ; 25(4): 2621-2634, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38457653

RESUMO

Postpolymerization modification of highly defined "scaffold" polymers is a promising approach for overcoming the existing limitations of controlled radical polymerization such as batch-to-batch inconsistencies, accessibility to different monomers, and compatibility with harsh synthesis conditions. Using multiple physicochemical characterization techniques, we demonstrate that poly(2-vinyl-4,4-dimethyl azlactone) (PVDMA) scaffolds can be efficiently modified with a coumarin derivative, doxorubicin, and camptothecin small molecule drugs. Subsequently, we show that coumarin-modified PVDMA has a high cellular biocompatibility and that coumarin derivatives are liberated from the polymer in the intracellular environment for cytosolic accumulation. In addition, we report the pharmacokinetics, biodistribution, and antitumor efficacy of a PVDMA-based polymer for the first time, demonstrating unique accumulation patterns based on the administration route (i.e., intravenous vs oral), efficient tumor uptake, and tumor growth inhibition in 4T1 orthotopic triple negative breast cancer (TNBC) xenografts. This work establishes the utility of PVDMA as a versatile chemical platform for producing polymer-drug conjugates with a tunable, stimuli-responsive delivery.


Assuntos
Lactonas , Neoplasias , Polímeros , Humanos , Distribuição Tecidual , Polímeros/química , Polivinil/química , Cloreto de Polivinila , Doxorrubicina/farmacologia
12.
Inorg Chem ; 63(31): 14699-14711, 2024 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-39047187

RESUMO

The selective separation and purification of artesunate (ARU) and artemisinin (ART) using zirconium-based metal-organic frameworks (MOF), especially UiO-66 MOF, are receiving increasing attention. In this study, tunable "hydrophobic" sites of thiol (-SH) were introduced to amino-functionalized MOFs (UiO-66-NH2) to fabricate a thiol-amino bifunctional UiO-66/polyvinylidene fluoride (PVDF)-blended membrane (S1-UiO/PVDF-DPIM) via the delayed-phase-inversion method for selective separation of ARU/ART. The adsorption results indicated that the modification of UiO-66-NH2 with thiol can indeed increase the ARU adsorption. The thiol-functional MOF (S1-UiO-66-NH2) was chosen as the optimal thiol-amino bifunctional MOF, as it possessed the maximum ARU adsorption capacity (111.14 mg g-1) and the highest selective-separation factor (α = 51.84). The ATR FT-IR dynamic spectrum disclosed the recognition mechanism, indicating that incorporating thiol groups into a hydrophilic MOF as hydrophobic sites can boost adsorption efficiency. Moreover, the static-selective permeation results showed that the S1-UiO/PVDF-DPIM preferentially transfers ARU when mixed with ART, even achieving complete ARU/ART separation. The most crucial aspect was the introduction of a hydrophobic core of -SH and new spontaneously formed disulfide bonds to S1-UiO/PVDF-DPIM, creating alternated hydrogen bonds and hydrophobic interactions. This work provides an alternative strategy to prepare hydrophobic-hydrophilic MOF-based membranes for the highly efficient and selective separation of complex analogue systems.


Assuntos
Artesunato , Interações Hidrofóbicas e Hidrofílicas , Estruturas Metalorgânicas , Compostos de Sulfidrila , Estruturas Metalorgânicas/química , Estruturas Metalorgânicas/síntese química , Compostos de Sulfidrila/química , Compostos de Sulfidrila/isolamento & purificação , Artesunato/química , Artesunato/farmacologia , Artesunato/isolamento & purificação , Adsorção , Polivinil/química , Membranas Artificiais , Estrutura Molecular , Artemisininas/química , Artemisininas/isolamento & purificação , Zircônio/química , Propriedades de Superfície , Polímeros de Fluorcarboneto , Ácidos Ftálicos
13.
Nanotechnology ; 35(36)2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38861959

RESUMO

Here we report the liquid-solid interaction in droplet-based triboelectric nanogenerators (TENG) for estimation of human Na+/K+levels. The exploitation of PVDF-HFP encapsulated WS2as active layer in the droplet-based TENG (DTENG) leads to the generation of electrical signal during the impact of water droplet. Comparison over the control devices indicates that surface quality and dielectric nature of the PVDF-HFP/WS2composite largely dictates the performance of the DTENG. The demonstration of excellent sensitivity of the DTENG towards water quality indicates its promising application towards water testing. In addition, the alteration in output signal with slightest variation in ionic concentration (Na+or K+) in water has been witnessed and is interpreted with charge transfer and ion transfer processes during liquid-solid interaction. The study reveals that the ion mobility largely affects the ion adsorption process on the active layer of PVDF-HFP/WS2and thus generates distinct output profiles for diverse ions like Na+and K+. Following that, the DTENG characteristics have been exploited to artificial urine where the varying output signals have been recorded for variation in urinary Na+ion concentration. Therefore, the deployment of PVDF-HFP/WS2in DTENG holds promising application towards the analyse of ionic characteristics of body fluids.


Assuntos
Nanoestruturas , Polímeros de Fluorcarboneto/química , Polivinil/química , Nanoestruturas/química , Cápsulas , Compostos de Tungstênio/química , Sulfetos/química , Eletricidade , Potássio/química , Íons/química , Cloro/química
14.
Macromol Rapid Commun ; 45(4): e2300585, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37931222

RESUMO

Flexible dielectrics with large dielectric constant (ε') coupled with low loss are highly pursued in many applications. To bolster the ε' of raw Zn (zinc)/poly(vinylidene fluoride, PVDF) while maintaining pimping dielectric loss, in this study, the core@double-shell structured Zn@zinc carbonate (ZnCH)@polystyrene (PS) particles are first synthesized through a suspension polymerization of styrene, and then composited with PVDF to elevate the ε' and keep low loss of the composites. By optimizing the PS shells' thickness and tailoring the electrical resistivity of Zn@ZnCH@PS particles, both the slow inter-particle polarization and fast intra-particle polarization in the composites can be decoupled and synergistically tuned, thus, the Zn@ZnCH@PS/PVDF achieves a much higher ε' and lower dielectric loss, simultaneously, which far exceed the unmodified Zn/PVDF. Both experiment and theoretic calculation reveal that the double-shell ZnCH@PS not only induces and promotes multiple polarizations enhancing the composites' ε', especially at the optimized PS's thickness, but also maintains suppressed loss and conductivity thanks to their obvious barrier effect on long-range charge migration. The core@double-shell filler design strategy facilitates the development of polymer composites with desirable dielectric properties for applications in electronic and electrical power systems.


Assuntos
Polímeros de Fluorcarboneto , Poliestirenos , Polivinil , Condutividade Elétrica , Zinco
15.
Macromol Rapid Commun ; 45(2): e2300485, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37906622

RESUMO

The residual polarization of antiferroelectric ceramics is very small, yet they possess high energy storage density and efficiency. Incorporating antiferroelectric ceramic particles into a polymer matrix is beneficial for improving the energy storage performance of composites. However, excessive amounts of ceramic particles can lead to aggregation within the polymer, resulting in defects and a significant reduction in composite film performance. In this study, the antiferroelectric AgNbO3 is selected as the filler and modified with silane coupling agent KH550. poly(vinylidene fluoride) (PVDF) and polymethyl methacrylate (PMMA) are blended as the matrix, and the energy storage performance of the composite is improved by adjusting the additional amount of PVDF. The structure, dielectric properties, and energy storage properties of the composites are systematically studied. The results show that hydrogen bonds are formed between PVDF and PMMA, and PVDF and PMMA are tightly bonded under the action of hydrogen bonds. The compatibility of PVDF with PMMA is optimal when the mass fraction of PVDF is 30 wt%. Moreover, with the synergistic effect of the antiferroelectric filler AgNbO3 , the breakdown strength of AgNbO3 /PVDF/PMMA composites reaches 430 kV mm-1 , and the energy storage density reaches 14.35 J cm-3 .


Assuntos
Polímeros de Fluorcarboneto , Polímeros , Polimetil Metacrilato , Polivinil , Cerâmica
16.
Macromol Rapid Commun ; 45(8): e2300674, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38234077

RESUMO

Defined, branched polymer architectures with low dispersity and architectural purity are of great interest to polymer science but are challenging to synthesize. Besides star and comb, especially the pom-pom topology is of interest as it is the simplest topology with exactly two branching points. Most synthetic approaches to a pom-pom topology reported a lack of full control and variability over one of the three topological parameters, the backbone or arm molecular weight and arm number. A new, elegant, fast, and scalable synthetic route without the need for post-polymerization modification (PPM) or purification steps during the synthesis to a pom-pom and a broad variety of topologies made from styrene and dienes is reported, with potential application to barbwire, bottlebrush, miktoarm star, Janus type polymers, or multi-graft copolymers. The key is to inset short poly(2-vinyl-pyridine) blocks (<2 mol% in the branched product) into the backbone as branching points. Carb anions can react at the C6 carbon of the pyridine ring, grafting the arms onto the backbone. Since the synthetic route to polystyrene pom-poms has only two steps and is free of PPM or purification, large amounts of up to 300 g of defined pom-pom structures can be synthesized in one batch.


Assuntos
Ânions , Polimerização , Poliestirenos , Poliestirenos/química , Ânions/química , Estrutura Molecular , Polímeros/química , Polímeros/síntese química , Polivinil/química , Polivinil/síntese química
17.
Macromol Rapid Commun ; 45(16): e2400168, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38644552

RESUMO

This study focuses on the development of regiospecific hydroarylation polyaddition of naphthalene- and carbazole-based monomers with diynes under mild reaction conditions at room temperature. A 1-pyrazole substituent serves as an appropriate directing group for a Co-catalyst to efficiently activate the C-H bonds of generally inactive six-membered aromatic hydrocarbons. The 1-pyrazole groups in 2,6-di(1-pyrazolyl)naphthalene adopt planar conformations and act as directing groups, resulting in a smooth hydroarylation reaction. In contrast, the reaction with 1,5-di(1-pyrazolyl)naphthalene do not proceed. The polyaddition reaction of 2,6-di(1-pyrazolyl)naphthalene selectively proceeds at 3,7-positions under mild reaction conditions at 30 °C, and yields corresponding poly(arylenevinylene) (PAV) with high molecular weight. This molecular design is also applicable to the hydroarylation polyaddition of carbazole; the polyaddition reaction of 9-(2-ethylhexyl)-3,6-di(1-pyrazolyl)carbazole selectively occurred at 2,7-positions. The optical and electronic properties of the synthesized compounds are evaluated. The obtained PAVs serve as an emitting material in organic light-emitting diode (OLED). This study aims to develop a Co-catalyzed hydroarylation polyaddition via C-H activation of generally inactive polyaromatic hydrocarbons (PAHs) under mild conditions.


Assuntos
Carbazóis , Naftalenos , Carbazóis/química , Carbazóis/síntese química , Catálise , Naftalenos/química , Naftalenos/síntese química , Estrutura Molecular , Polivinil/química , Polivinil/síntese química , Reação de Cicloadição , Estereoisomerismo
18.
Macromol Rapid Commun ; 45(15): e2400148, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38733365

RESUMO

Flexoelectricity is the universal electric polarization of dielectrics upon exertion of a non-uniform strain gradient. With the advancement of nano-technology and miniaturization of electronic devices, flexoelectricity holds the promise to address the power requirements for such device operation. The direct flexoelectric effect in liquid crystal (LC) embedded poly(vinylidene fluoride) (PVDF) polymer films is examined for the first time by the application of external strain on the films. Physical characterizations such as Differential Scanning Calorimetry (DSC), dielectric spectroscopy, X-ray diffraction, and field emission scanning electron microscopy (FESEM) are carried out to study the composite films' intrinsic and extrinsic properties like dielectric, crystallinity, and morphologies. The value of the flexoelectric coefficient (µ12) increases with the concentration of LC incorporation. At 3 wt%, µ12 attains a maximum value of 68 nC m-1, which is more than a threefold increase compared to that of the pure PVDF film. The role of Maxwell-Wagner-Sillars (MWS) polarization in determining flexoelectric polarization in polymer composites is also discussed. Moreover, the influence of the microstructure and domain size formation in determining the flexoelectric response are discussed in detail to infer the behavior of the flexoelectric coefficients of the films. Potential device applications based on this phenomenon have been proposed for future research in sensing and actuation.


Assuntos
Cristais Líquidos , Polivinil , Polivinil/química , Cristais Líquidos/química , Polímeros/química , Fontes de Energia Elétrica , Polímeros de Fluorcarboneto
19.
Macromol Rapid Commun ; 45(6): e2300619, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38232954

RESUMO

Piezoelectric nanogenerator (PENG) produces stable electrical signals in response to external mechanical stimuli and holds promise in the fields of flexible sensors and smart wearable devices. In practice, a high-performance PENG with a straightforward structure and exceptional reliability is deeply desired. This study optimally synthesizes piezoelectric composites comprising polyvinylidene fluoride (PVDF) incorporated with barium titanate (BTO) nanoparticles (NPs) and fabricated a PENG with heightened sensitivity by using the electrospinning technique. The polar ß-phase content of the dual-optimized BTO-PVDF (barium titanate and polyvinylidene fluoride) electrospun fiber reaches up to 82.39%. In the bending mode, it achieves a remarkable maximum open-circuit voltage of 19.152 V, a transferred charge of 8.058 nC, and an output voltage per unit area of 2.128 V cm- 2. Under vertical pressure conditions, the BP-PENG exhibits an impressive voltage of 12.361 V while the force is 2.156 N, demonstrating a notable pressure sensing sensitivity of 5.159 V kPa-1, with an excellent linear relationship. Furthermore, the BP-PENG displays sensitive sensing features in monitoring hand movements. The sensitive response and high performance make it promising for applications in human motion monitoring and smart wearable devices.


Assuntos
Polímeros de Fluorcarboneto , Nanofibras , Polivinil , Humanos , Bário , Reprodutibilidade dos Testes , Eletricidade
20.
Macromol Rapid Commun ; 45(14): e2400093, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38639102

RESUMO

The formation of ABC triblock terpolymers through solution casting is still challenging. In this study, core-shell double gyroid network structures are fabricated via solution casting using poly(2,2,2-trifluoroethyl methacrylate) (PTFEMA) (F)-b-[poly(4-vinylpyridine) (P4VP) (P)]-b-[polystyrene (PS) (S)] (FPS) triblock terpolymers in N,N-dimethylformamide (DMF). Upon heat treatment, the polymer tends to form a sphere-in-lamellar structure at the F/S interface. Given the solubility properties of each component in DMF, it is anticipated that the effective volume fraction of F relative to P would increase in concentrated solutions and the effective volume fraction of S would decrease. The microphase-separated structure derived from the DMF solution consistently results in the formation of a network structure composed of a core-shell double gyroid, with F as the matrix, P as the shell, and S as the core, and their periodic lengths gradually increase to 110.8, 131.8, and 162.7 nm as increase molecular weights of PS blocks to 13.8, 20.7, and 28.8 kg mol-1. Based on the solubility properties of the polymer components highlighted in this study, the solvent selection strategy is broadly applicable to ABC triblock terpolymers featuring various polymer components, offering a more efficient avenue for fabricating core-shell double gyroid structures.


Assuntos
Polímeros , Solubilidade , Polímeros/química , Dimetilformamida/química , Polivinil/química , Estrutura Molecular , Poliestirenos/química , Solventes/química , Tamanho da Partícula
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