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1.
Angew Chem Int Ed Engl ; : e202416114, 2024 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-39376066

RESUMO

Natural photosynthetic systems require spatiotemporal organization to optimize photosensitized reactions and maintain overall efficiency, involving the hierarchical self-assembly of photosynthetic components and their stabilization through synergistic interactions. However, replicating this level of organization is challenging due to the difficulty in efficiently communicating supramolecular nano-assemblies with nanoparticles or biological architectures, owing to their dynamic instability. Herein, we demonstrate that the supramolecular reconstruction of self-assembled amphiphilic rhodamine B nanospheres (RN) through treatment with metal-phenolic coordination complexes results in the formation of a stable hybrid structure. This reconstructed structure enhances electron transfer efficiency, leading to improved photocatalytic performance. Due to the photoluminescence quenching property of RN and its electronic synergy with tannic acid (T) and zirconium (Z), the supramolecular complexes of hybrid nanospheres (RNTxZy) with Pt nanoparticles or a biological workhorse, Shewanella oneidensis MR-1, showed marked improvement in photocatalytic hydrogen production. The supramolecular hybrid particles with a metal-phenolic coordination layer showed 5.6- and 4.0-fold increases, respectively, in the productivities of hydrogen evolution catalyzed by Pt (Pt/RNTxZy) and MR-1 (M/RNTxZy), respectively. These results highlight the potential for further advancements in the structural and photochemical control of supramolecular nanomaterials for energy harvesting and bio-hybrid systems.

2.
J Comput Chem ; 41(13): 1261-1270, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32058612

RESUMO

The interaction of a carbon nanotube (CNT) with various aromatic molecules, such as aniline, benzophenone, and diphenylamine, was studied using density functional theory able to compute intermolecular weak interactions (B3LYP-D3). CNTs of varying lengths were used, such as 4-CNT, 6-CNT, and 8-CNT (the numbers denoting relative lengths), with the lengths being chosen appropriately to save computation times. All aromatic molecules were found to exhibit strong intermolecular binding energies with the inner surface of the CNT, rather than the outer surface. Hydrogen bonding between two aromatic molecules that include N and O atoms is shown to further stabilize the intermolecular adsorption process. Therefore, when benzophenone and diphenylamine were simultaneously allowed to interact with a CNT, the aromatic molecules were expected to preferably enter the CNT. Furthermore, additional calculations of the intermolecular adsorption energy for aniline adsorbed on a graphene surface showed that the concavity of graphene-like carbon sheet is in proportion to the intermolecular binding energy between the graphene-like carbon sheet and the aromatic molecule.

3.
Angew Chem Int Ed Engl ; 56(20): 5485-5489, 2017 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-28334479

RESUMO

The coordination chemistry of plant polyphenols and metal ions can be used for coating various substrates and for creating modular superstructures. We herein explored this chemistry for the controlled release of guests from mesoporous silica nanoparticles (MSNs). The selective adsorption of tannic acids (TAs) on MSN silica walls opens the MSN mesoporous channels without disturbing mass transport. The channel may be closed by the coordination of TA with CuII ions. Upon exposure to light, photolysis of Trojan horse guests (photoacid generators, PAGs) leads to acid generation, which enables the release of payloads by decomposing the outer coordination shell consisting of TA and CuII . We also fabricated a modular assembly of MSNs on glass substrates. The photoresponsive release characteristics of the resulting film are similar to those of the individual MSNs. This method is a fast and facile strategy for producing photoresponsive nanocontainers by non-covalent engineering of MSN surfaces that should be suitable for various applications in materials science.

4.
Angew Chem Int Ed Engl ; 56(51): 16180-16185, 2017 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-29024369

RESUMO

We herein report a facile, cost-competitive, and scalable method for producing viscoelastic conductors via one-pot melt-blending using polymers and supramolecular gels composed of carbon nanotubes (CNTs), diphenylamine (DP), and benzophenone (BP). When mixed, a non-volatile eutectic liquid (EL) produced by simply blending DP with BP (1:1 molar ratio) enabled not only the gelation of CNTs (EL-CNTs) but also the dissolution of a number of commodity polymers. To make use of these advantages, viscoelastic conductors were produced via one-pot melt-blending the EL and CNTs with a model thermoplastic elastomer, poly(styrene-b-butadiene-b-styrene) (SBS, styrene 30 wt %). The resulting composites displayed an excellent electromechanical sensory along with re-mendable properties. This simple method using cost-competitive EL components is expected to provide an alternative to the use of expensive ionic liquids as well as to facilitate the fabrication of novel composites for various purposes.

5.
Angew Chem Int Ed Engl ; 54(36): 10483-7, 2015 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-26212227

RESUMO

We report here a strategy for influencing the phase and lattice of the inverse mesophases of a single branched-linear block copolymer (BCP) in solution which does not require changing the structure of the BCP. The phase of the self-assembled structures of the block copolymer can be controlled ranging from bilayer structures of positive curvature (polymersomes) to inverse mesophases (triply periodic minimal surfaces and inverse hexagonal structures) by adjusting the solvent used for self-assembly. By using solvent mixtures to dissolve the block copolymer we were able to systematically change the affinity of the solvent toward the polystyrene block, which resulted in the formation of inverse mesophases with the desired lattice by self-assembly of a single branched-linear block copolymer. Our method was also applied to a new solution self-assembly method for a branched-linear block copolymer on a stationary substrate under humidity, which resulted in the formation of large mesoporous films. Our results constitute the first controlled transition of the inverse mesophases of block copolymers by adjusting the solvent composition.

6.
Transfusion ; 54(6): 1542-51, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24313463

RESUMO

BACKGROUND: Transfusional iron overload and its consequences are challenges in chronically transfused patients with myelodysplastic syndromes (MDSs) or aplastic anemia (AA). STUDY DESIGN AND METHODS: This was a prospective, multicenter, open-label study to investigate the efficacy of deferasirox (DFX) by serial measurement of serum ferritin (S-ferritin) level, liver iron concentration (LIC) level using relaxation rates magnetic resonance imaging, and other laboratory variables in patients with MDS or AA. RESULTS: A total of 96 patients showing S-ferritin level of at least 1000 ng/mL received daily DFX for up to 1 year. At the end of the study, S-ferritin level was significantly decreased in MDS (p=0.02366) and AA (p=0.0009). LIC level was also significantly reduced by more than 6.7 mg Fe/g dry weight from baseline. Hemoglobin level and platelet counts were significantly increased from baseline (p=0.002 and p=0.025, respectively) for patients showing significant anemia or thrombocytopenia. Elevated alanine aminotransferase was also significantly decreased from baseline. CONCLUSIONS: This study shows that DFX is effective in reducing S-ferritin and LIC level in transfusional iron overload patients with MDS or AA and is well tolerated. In addition, positive effects in hematologic and hepatic function can be expected with DFX. Iron chelation treatment should be considered in transfused patients with MDS and AA when transfusion-related iron overload is documented.


Assuntos
Anemia Aplástica/terapia , Benzoatos/uso terapêutico , Sobrecarga de Ferro/tratamento farmacológico , Ferro/metabolismo , Fígado/metabolismo , Síndromes Mielodisplásicas/terapia , Reação Transfusional , Triazóis/uso terapêutico , Adulto , Idoso , Deferasirox , Feminino , Ferritinas/sangue , Humanos , Fígado/efeitos dos fármacos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
7.
Jpn J Clin Oncol ; 44(2): 153-8, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24298042

RESUMO

OBJECTIVE: The purpose of this study was to investigate the quality of life among cancer survivors compared with individuals without a history of cancer (noncancer controls) using the Korea National Health and Nutrition Examination Survey. METHODS: The study subjects were 783 adult cancer survivors and 36 456 noncancer controls who participated in the third, fourth and fifth Korea National Health and Nutrition Examination Survey. Demographic factors, health-related behavior, clinical characteristics and health-related quality of life were assessed with self-reported questionnaires. The EuroQoL-5Dimension was used to evaluate health-related quality of life. Descriptive statistics and multiple regression analysis were used to compare health-related quality of life between cancer survivors and noncancer controls. RESULTS: About 67% were women and the mean age of the cancer survivors was 60.9 ± 12.4 years. About 52% of survivors were diagnosed with cancer between 45 and 64 years, and more than half of cancer survivors were diagnosed 5 years or less before the interview. The pain/discomfort dimension was the highest reported problem: 43.6% for cancer survivors. The proportion of any reported problem was significantly higher among cancer survivors compared with noncancer controls in terms of mobility (adjusted odds ratio (aOR), 1.56, 95% confidence interval, 1.24-1.97), usual activities (aOR, 1.45, 95% confidence interval, 1.11-1.89), pain/discomfort (aOR, 1.26, 95% confidence interval, 1.04-1.52) and anxiety/depression (aOR, 1.61, 95% confidence interval, 1.29-2.01). CONCLUSIONS: Cancer survivors had a significantly lower quality of life compared with noncancer controls. The pain/discomfort dimension was the highest reported problem in cancer survivors.


Assuntos
Neoplasias , Qualidade de Vida , Sobreviventes , Adulto , Idoso , Feminino , Nível de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , República da Coreia/epidemiologia , Inquéritos e Questionários , Sobreviventes/estatística & dados numéricos
8.
Angew Chem Int Ed Engl ; 53(16): 4102-6, 2014 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-24554521

RESUMO

A facile, scalable route to new nanocomposites that are based on carbon nanotubes/heteroatom-doped carbon (CNT/HDC) core-sheath nanostructures is reported. These nanostructures were prepared by the adsorption of heteroatom-containing ionic liquids on the walls of CNTs, followed by carbonization. The design of the CNT/HDC composite allows for combining the electrical conductivity of the CNTs with the catalytic activity of the heteroatom-containing HDC sheath layers. The CNT/HDC nanostructures are highly active electrocatalysts for the oxygen reduction reaction and displayed one of the best performances among heteroatom-doped nanocarbon catalysts in terms of half-wave potential and kinetic current density. The four-electron selectivity and the exchange current density of the CNT/HDC nanostructures are comparable with those of a Pt/C catalyst, and the CNT/HDC composites were superior to Pt/C in terms of long-term durability and poison tolerance. Furthermore, an alkaline fuel cell that employs a CNT/HDC nanostructure as the cathode catalyst shows very high current and power densities, which sheds light on the practical applicability of these new nanocomposites.

9.
Anticancer Res ; 44(1): 347-359, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38160001

RESUMO

BACKGROUND/AIM: This study investigated the treatment patterns and prognosis of patients with metastatic or unresectable colorectal cancer (mCRC) treated with chemotherapy with targeting agents. PATIENTS AND METHODS: This longitudinal multicenter study included 963 patients with mCRC who were treated in Korea between 2016 and 2020. Treatment patterns and efficacy were compared according to the mutation status and clinical factors. RESULTS: As first-line therapy, most of the patients (83.5%) received FOLFOX plus bevacizumab (35.4%), followed by FOLFIRI plus bevacizumab (18.8%), FOLFIRI plus cetuximab (17.0%), and FOLFOX plus cetuximab (12.3%). Bevacizumab was the most frequent agent (78.8%) combined with chemotherapy in RAS-mutated CRC, while cetuximab (57.2%) in RAS wild-type CRC. Cetuximab was frequently combined with a doublet regimen in patients with left-sided CRC than in those with right-sided CRC (34.4% vs. 16%). As second-line therapy, most patients (63.4%) also received doublet regimens with bevacizumab, and FOLFIRI plus aflibercept was administered in 15.1%. The objective response rate with FOLFIRI plus cetuximab was significantly higher in patients with left-sided CRC than in those with right-sided CRC (59.2% vs. 30.8%, p=0.008) and marginally higher in patients with RAS wild-type CRC than in those with RAS-mutated CRC (55.6% vs. 0.0%, p=0.092). Progression-free survival (PFS) with FOLFOX plus bevacizumab was significantly shorter than that with FOLFIRI plus bevacizumab (p=0.030) in RAS-mutated CRC, whereas there were no significant differences between regimens in RAS wild-type CRC. CONCLUSION: In patients with unresectable metastatic colorectal cancer, doublet chemotherapy with targeting agents is the most common therapy and efficacy depends on the mutation status as well as clinical factors.


Assuntos
Neoplasias do Colo , Neoplasias Colorretais , Neoplasias Retais , Humanos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Bevacizumab/uso terapêutico , Cetuximab , Neoplasias do Colo/tratamento farmacológico , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Prognóstico , Neoplasias Retais/tratamento farmacológico
10.
Jpn J Clin Oncol ; 43(10): 981-7, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23975890

RESUMO

OBJECTIVE: This study aimed to describe the health behaviors of cancer survivors in the Republic of Korea and to compare them with the health behaviors of two control groups: (i) individuals with no history of cancer but with other chronic diseases and (ii) individuals with no history of cancer or other chronic diseases. METHODS: This is a cross-sectional study of 17 311 adults at least 19 years of age who participated in the Fourth Korea National Health and Nutrition Examination Survey (2007-09). Smoking, alcohol drinking, physical activity and cancer screening behaviors of cancer survivors were assessed and compared with those of the two control groups. χ(2) tests and multiple logistic regression analyses were performed to determine the likelihood and predictors of health behaviors. RESULTS: The proportion of cancer survivors who were current smokers, heavy drinkers and engaged in physical activity were 9.6, 6.6 and 26.0%, respectively. Cancer screening rates reported among survivors were 44.2, 17.0, 49.8 and 47.7% for stomach, colorectal, breast and cervical cancers, respectively. Cancer survivors showed lower smoking and alcohol drinking rates compared with both control groups after adjusting for sex, age, marital status, education, household income and health insurance. Cancer survivors also showed stomach, breast and cervical cancer screening rates that differed from both control groups. However, in multiple analyses, these differences were not significant. CONCLUSIONS: Cancer survivors are more likely to adopt good health behaviors than individuals without a history of cancer. Further study is needed to determine the factors that lead to continued unhealthy behaviors after cancer diagnosis.


Assuntos
Consumo de Bebidas Alcoólicas/epidemiologia , Detecção Precoce de Câncer/estatística & dados numéricos , Comportamentos Relacionados com a Saúde , Atividade Motora , Neoplasias , Fumar/epidemiologia , Sobreviventes/estatística & dados numéricos , Adulto , Idoso , Neoplasias da Mama , Estudos Transversais , Feminino , Humanos , Coreia (Geográfico)/epidemiologia , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Neoplasias/prevenção & controle , Inquéritos Nutricionais , Prevenção Secundária , Neoplasias Gástricas , Neoplasias do Colo do Útero
11.
Adv Mater ; 34(50): e2206982, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36121423

RESUMO

Freshwater shortage is becoming one of the most critical global challenges owing to severe water pollution caused by micropollutants and volatile organic compounds (VOCs). However, current purification technology shows slow adsorption of micropollutants and requires an energy-intensive process for VOCs removal from water. In this study, a highly efficient molecularly engineered covalent triazine framework (CTF) for rapid adsorption of micropollutants and VOC-intercepting performance using solar distillation is reported. Supramolecular design and mild oxidation of CTFs (CTF-OXs) enable hydrophilic internal channels and improve molecular sieving of micropollutants. CTF-OX shows rapid removal efficiency of micropollutants (>99.9% in 10 s) and can be regenerated several times without performance loss. Uptake rates of selected micropollutants are high, with initial pollutant uptake rates of 21.9 g mg-1  min-1 , which are the highest rates recorded for bisphenol A (BPA) adsorption. Additionally, photothermal composite membrane fabrication using CTF-OX exhibits high VOC rejection rate (up to 98%) under 1 sun irradiation (1 kW m-2 ). A prototype of synergistic purification system composed of adsorption and solar-driven membrane can efficiently remove over 99.9% of mixed phenol derivatives. This study provides an effective strategy for rapid removal of micropollutants and high VOC rejection via solar-driven evaporation process.

12.
J Am Chem Soc ; 133(9): 2840-3, 2011 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-21314183

RESUMO

When poly(isopropylidene diallylmalonate) rich in threo-disyndiotactic sequences (st(rich)-2) was utilized as a cross-linkable ink for microcontact printing, the resultant submicrometer-scale patterns featuring 700 and 300 nm wide stripes were successfully insolubilized while maintaining their high dimensional integrity by heat-induced cross-linking with elimination of CO(2) and acetone. In sharp contrast, although the thermal properties and reactivities of a polymer rich in threo-diisotactic sequences (it(rich)-2) and a polymer having low stereoregularity (2(low)) are little different from those of st(rich)-2, the patterns printed with these reference polymers collapsed considerably upon heating as a result of a volume shrinkage effect. The striking difference between st(rich)-2 and the other two polymers most likely arises from the nanofiber-forming character of st(rich)-2, where the printed stripes are porous and much less affected by the volume shrinkage of individual nanofibers.

13.
ACS Nano ; 15(9): 14580-14586, 2021 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-34499481

RESUMO

Recent advances have led to the development of intelligent drug-delivery systems such as microchips, micropumps, and soft devices with sensors; however, the facile preparation of transdermal and implantable systems modulable to various stimuli remains elusive. In addition, the use of a battery limits their wearable and implantable applications. Therefore, to overcome these disadvantages, we herein suggest a facile strategy to prepare electro-mechanochemically responsive soft gel composites with molecular gatekeeper-based nanocontainers. We found that a metal-phenolic coordination network can act as an efficient self-healable and adaptive gatekeeper in response to electrical and mechanical stimuli owing to the reversible dynamic bonds and adhesiveness to the silica surface. The porous channels of mesoporous silica nanoparticles are filled with guest molecules, and the exterior is wrapped with metal-tannic acid (TA) networks. Owing to the robustness of metal-phenolic network, the guest molecules are efficiently entrapped in the channels but released by electrical and ultrasound input. Voltage-dependent changes in the guest release rate provide control over the dosage on demand. The combination of hydrogel matrixes with the responsive nanocapsules enables the construction of a series of adaptive gel composites capable of successive guest release in response to electrical, ultrasound, electromechanical, and triboelectric stimuli. The Korsmeyer-Peppas model revealed that the release mechanism is non-Fickian, which indicates the presence of boundaries around the guest-loading channels (n = 0.739, R2 = 0.9574 when 2 V is applied). This study realized efficient platforms for active-type drug-delivery applications based on transdermal patches and implantable gels with remotely controllable release characteristics.


Assuntos
Sistemas de Liberação de Medicamentos , Géis , Nanoestruturas
14.
J Am Chem Soc ; 131(46): 16614-5, 2009 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-19919132

RESUMO

The cyclodextrin covered porous silica nanoparticles (Si-MPs) exhibited enzyme responsive characteristics. The cyclodextrin gatekeepers on the surface of Si-MPs can be hydrolyzed by a-amylase to release guest molecules from the porous reservoir. The ester linkage in the stalk part of the cyclodextrin gatekeeper can also be cleaved by lipase to release guests from the channel. Our approach would provide a unique methodology for controlled delivery systems.


Assuntos
Ciclodextrinas/química , Nanoestruturas/química , Dióxido de Silício/química , alfa-Amilases/química , Hidrólise
15.
Angew Chem Int Ed Engl ; 48(7): 1275-8, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19137522

RESUMO

Springing the trap: Cyclodextrin-covered mesoporous silica nanoparticles with photocleavable linkers exhibit photoinduced release characteristics and a sol-gel transition that is induced by molecular recognition (see picture). Upon exposure to UV light, the guest molecules were released from the pore by removal of the CD "gatekeeper", which was linked on the surface of the silica nanoparticle through a photocleavable o-nitrobenzyl ester moiety.


Assuntos
Ciclodextrinas/química , Ciclodextrinas/metabolismo , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Estrutura Molecular , Transição de Fase , Fotoquímica , Dióxido de Silício/química , Raios Ultravioleta
16.
Chem Commun (Camb) ; (48): 6570-2, 2008 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-19057782

RESUMO

We report biocompatible, cell-permeable core-shell-corona polymer micelles bearing glutathione-cleavable shell cross-links, which allow the facilitated release of entrapped anticancer drugs at cytoplasm in response to an intracellular glutathione level.


Assuntos
Aminoácidos/química , Dissulfetos/química , Sistemas de Liberação de Medicamentos , Glutationa/química , Micelas , Polietilenoglicóis/química
17.
Chem Commun (Camb) ; (46): 4887-9, 2007 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-18361358

RESUMO

We have synthesized a highly efficient organic dye for a dye-sensitized solar cell; the overall solar-to-energy conversion efficiency was 9.1% at AM 1.5 illumination (100 mW cm(-2)): short-circuit current density (J(sc)) = 18.1 mA cm(-2), open circuit photovoltage (V(oc)) = 743 mV and fill factor (ff) = 0.675.

18.
Diagn Microbiol Infect Dis ; 89(1): 1-6, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28679481

RESUMO

This retrospective study aimed to evaluate the levels of coagulation factors and presence of disseminated intravascular coagulation (DIC) in patients with scrub typhus. We included patients confirmed to have scrub typhus at the Chosun University Hospital between September 2004 and December 2009. The DIC scores were evaluated in 365 patients and 36 healthy controls. The median concentrations of fibrinogen, d-dimer, and fibrin/fibrinogen degradation products (FDP) were compared between patients and healthy controls (p<0.001 for all tests). Patients with scrub typhus had longer prothrombin time and lower platelet counts than the controls. Major bleeding was observed in 18/365 patients with scrub typhus. Fifty-one (14.0%) patients presented with severe complications of scrub typhus. Overt DIC and thrombocytopenia (<100,000 platelets/mm3) were observed more frequently in patients with bleeding and severe illness. Furthermore, median platelet counts were low in both groups. Approximately 2.7% (n=10) and 16.4% (n=60) patients with scrub typhus had overt DIC, as defined by the International Society on Thrombosis and Hemostasis DIC score (DIC1) and the DIC-scoring template with a fibrinogen/C-reactive protein-ratio (DIC2), respectively. Three (16.7%) and 10 (55.6%) patients with bleeding had overt DIC, as defined by the DIC1 and DIC2, respectively. Seven (13.7%) and 26 (51%) patients with severe illness had overt DIC, as defined by DIC1 and DIC2, respectively. In conclusion, activation of the coagulation system is an important feature of scrub typhus and is correlated with severe disease, including bleeding. This is the first study to report a relationship between DIC and scrub typhus.


Assuntos
Coagulação Intravascular Disseminada/epidemiologia , Coagulação Intravascular Disseminada/patologia , Tifo por Ácaros/complicações , Tifo por Ácaros/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Coagulação Intravascular Disseminada/complicações , Feminino , Hemorragia/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , República da Coreia/epidemiologia , Estudos Retrospectivos , Trombocitopenia/complicações , Trombocitopenia/epidemiologia
19.
Chem Commun (Camb) ; (13): 1372-4, 2006 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-16550270

RESUMO

New macromolecular self-assembling building blocks, dendron-helical polypeptide copolymers, have been synthesized; these materials possess a well-defined 3-D shape and self-assemble in solution to form nanoribbon and lyotropic liquid crystalline phases.


Assuntos
Antracenos/química , Géis/química , Cristais Líquidos/química , Peptídeos/química , Polímeros/química , Microscopia Eletrônica de Transmissão , Estrutura Molecular
20.
Nat Chem ; 7(9): 730-6, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26291945

RESUMO

Graphene has shown much promise as an organic electronic material but, despite recent achievements in the production of few-layer graphene, the quantitative exfoliation of graphite into pristine single-layer graphene has remained one of the main challenges in developing practical devices. Recently, reduced graphene oxide has been recognized as a non-feasible alternative to graphene owing to variable defect types and levels, and attention is turning towards reliable methods for the high-throughput exfoliation of graphite. Here we report that microwave irradiation of graphite suspended in molecularly engineered oligomeric ionic liquids allows for ultrahigh-efficiency exfoliation (93% yield) with a high selectivity (95%) towards 'single-layer' graphene (that is, with thicknesses <1 nm) in a short processing time (30 minutes). The isolated graphene sheets show negligible structural deterioration. They are also readily redispersible in oligomeric ionic liquids up to ~100 mg ml(-1), and form physical gels in which an anisotropic orientation of graphene sheets, once induced by a magnetic field, is maintained.

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