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1.
Macromol Rapid Commun ; 44(1): e2100933, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-35150178

RESUMEN

Polymer solar cells (PSCs) with a bulk heterojunction (BHJ) device structure have incredible advantages, such as low-cost fabrication and flexibility. However, the power conversion efficiency (PCE) of BHJ PSCs needs to be further improved to realize their practical applications. In this study, boosted PCEs from PSCs based on BHJ composites incorporated with Fe3 O4 magnetic nanoparticles (MNPs), aligned by an external magnetic field (EMF), are reported. It is found that the coercive electric field within the Fe3 O4 MNPs generated by the EMF has a strong and positive influence on the charge generation, which results in a more than 10% increase in free charge carriers. Moreover, the coercive electric field speeds up the charge carrier transport and suppresses charge carrier recombination within PSCs. In addition, a shortened extraction time makes charge carriers more likely to make it to the electrodes. As a result, more than 15% enhancement in PCE is observed from the PSCs based on the BHJ composite incorporated with the Fe3 O4 MNPs and the EMF as compared with that based on the BHJ composite thin film. This work indicates that the incorporation of MNPs and the EMF is a facile way to enhance the PCEs of PSCs.


Asunto(s)
Electricidad , Eritromicina , Electrodos , Campos Magnéticos , Polímeros
2.
Anal Chem ; 93(29): 10301-10309, 2021 07 27.
Artículo en Inglés | MEDLINE | ID: mdl-34269562

RESUMEN

It is of great significance to disclose the diverse aging pathways for polymers under multiple factors, so as to predict and control the potential aging evolution. However, the current methods fail to distinguish multiple pathways (multi-paths) of polymer aging due to the lack of spatiotemporal resolution. In this work, using polyimide as a model polymer, the hydroxyl, carboxyl, and amino groups from the polyimide aging process were labeled using specific fluorescent probes through boron-oxygen, imine, and thiourea linkages, respectively. When the excitation and emission wavelengths of each fluorescent probe were controlled, the multi-paths in polyimide aging can be visualized individually and simultaneously in three-dimensional fluorescent images. The overall aging process under hydrothermal treatment was destructured into the pyrolysis and hydrolysis pathways. Three-dimensional dynamic studies discovered that the increased humidity, along with the decreased oxygen content, could hamper the pyrolysis reaction and accelerate the hydrolysis reaction, leading to severe degradation of the overall polyimide aging. More importantly, the oxygen showed a higher regulation coefficient in accelerating the pyrolysis reaction, than the water vapor in motivating the hydrolysis reactions. Such a multidimensional identification methodology is able to guide the long-term use of polymers and control their aging process to a harmless direction in advance by tuning the contents of oxygen and water vapor.


Asunto(s)
Colorantes Fluorescentes , Polímeros , Hidrólisis , Oxígeno , Pirólisis
3.
Chemistry ; 27(49): 12526-12534, 2021 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-34159653

RESUMEN

Polyimide memory materials with a donor-acceptor structure based on a charge-transfer mechanism exhibit great potential for next-generation information storage technology due to their outstanding high-temperature resistance and good dimensional and chemical stability. Precisely controlling memory performance by limited chemical decoration is one of core challenges in this field. Most reported work mainly focuses on designing novel and elaborate electron donors or acceptors for the expected memory behavior of polyimides; this takes a lot of time and is not always efficacious. Herein, we report a series of porphyrinated copolyimides coPI-Znx (x=5, 10, 20, 50, 80), where x represents the mole percentage of Zn ion in the central core of the porphyrin. Experimental and theoretical analysis indicate that the Zn ion could play a vital bridge role in promoting the formation and stabilization of a charge-transfer complex by enhancing the hybridization of local and charge transfer (HLCT) excitations of porphyrinated polyimides, endowing coPI-Znx with volatile random access memory performance and continuously tunable retention time. This work could provide one simple strategy to precisely regulate memory performance merely by altering the metal content in porphyrinated polyimides.

4.
Small ; 16(49): e2005659, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33201592

RESUMEN

Compared with typical binary polymeric memory materials, functional polymers with ternary memory performance possess significant potential to achieve ultra-high-density data storage. The reported ternary memory polymers are normally driven by dual-mechanism. However, the involved thermodynamically unstable mechanisms (field-induced conformation change or conductive filament formation/fracture) may result in the poor reliability of memory devices under high-temperature working atmosphere. Another strategy to realize ternary memory is introducing charge trapping/de-trapping mechanism by attaching charge trap atom/group at electron donor, which is proved not always effective. Moreover, the synergistic two mechanisms may have difficulty for clarifying the relationship between memory performance and chemical structures, which is the core issue of polymer memory materials. Besides, some multi-level memory materials need the cooperative participation of artificially setting compliance current, which is the extension of typical binary memory and may cause a more complicated technique and logic circuit. Herein, based on charge-transfer mechanism, a concise and effective strategy to realize ternary memory application is proposed. By inserting a Zn ion, the charge-transfer process occurring in electron donors can lead to the novel electrical tri-stability memory behaviors. This work can provide a novel idea for achieving reliable and intrinsic ternary high-density data storage applications.

5.
J Am Chem Soc ; 141(24): 9463-9467, 2019 06 19.
Artículo en Inglés | MEDLINE | ID: mdl-31184144

RESUMEN

Designing highly active oxygen reduction reaction (ORR) catalysts is crucial to boost the fuel cell economy. Previous research has mainly focused on Pt-based alloy catalysts in which surface Pt is the solely active site and the activity improvement was challenged by the discovered scaling relationship. Herein we report a new concept of utilizing dual active sites for the ORR and demonstrate its effectiveness by synthesizing a SnO x/Pt-Cu-Ni heterojunctioned catalyst. A maximum of 40% enhancement in the apparent specific activity, which corresponds to 10-fold enhancement on interface sites, is measured compared with pure Pt-Cu-Ni. Detailed investigations suggest an altered dual-site cascade mechanism wherein the first two steps occur on SnO x sites and the remaining steps occur on adjacent Pt sites, allowing a significant decrease in the energy barrier. This study with the suggested dual-site cascade mechanism shows the potential to overcome the ORR energy barrier bottleneck to develop highly active catalysts.

6.
Macromol Rapid Commun ; 39(20): e1800141, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29873136

RESUMEN

High strength and high modulus polyimide (HSHMPI) fibers are a type of novel high-performance organic fiber with an initial modulus higher than 90 GPa and extremely high tensile strength over 2.5 GPa realizing broad applications in the fields of electronic, engineering, aerospace, and atomic energy industries. There are currently two synthetic pathways, i.e., one-step and two-step methods, developed for the manufacture of HSHMPI fibers. An integrated fabrication process involving wet-spinning followed by thermal imidization is accepted as a typical two-step synthetic route for industrialization of HSHMPI fibers. In this article, the classification, synthetic method and technology, molecular structure, morphology, microstructures, and properties of HSHMPI fibers are summarized extensively. The effects of molecular structure and synthetic technology on the microstructures and overall performance of HSHMPI fibers are discussed. In addition, the trend in development and the application prospect of HSHMPI fibers are analyzed accordingly.


Asunto(s)
Módulo de Elasticidad , Imidas/síntesis química , Resistencia a la Tracción , Imidas/química , Ensayo de Materiales , Estructura Molecular , Propiedades de Superficie
7.
J Am Chem Soc ; 139(41): 14364-14367, 2017 10 18.
Artículo en Inglés | MEDLINE | ID: mdl-28985069

RESUMEN

We demonstrate here the synthesis of a novel class of metallo-supramolecular polymers with shackled structure, via the coordination of cyclic di(bis-terpyridine-triphenyl ether ester) ligands with ruthenium(II) ions. The constraint from the ring topology via the shackling of ligands provides novel properties to these metallo-supramolecular polymers, including the formation of dendritic crystals, red-shift of absorption bands in the UV-vis spectra from interchain charge-transfer transitions, and a typical flash-type memory behavior.

8.
Artículo en Inglés | MEDLINE | ID: mdl-38593385

RESUMEN

The compressive performance of organic fiber has always been a key problem, limiting its development. In this paper, silicon oxide, alumina, and titanium oxide particles were separately deposited on the surface of high-strength and high-modulus polyimide (PI) fibers to form a structural supporting shell by using a magnetron sputtering method. The theoretical thickness was calculated by thermogravimetric analysis in good agreement with the actual thickness determined from scanning electron microscopy. The mechanics, surface, and interface properties of the measured fibers were analyzed mainly from the aspects of surface energy, interfacial shear strength (IFSS), and compression strength. The results showed that after magnetron sputtering, the inorganic shells were uniformly deposited on the surface of PI fiber, resulting in an increase in the content of inorganic elements as well as the roughness. As a result, the surface energy and IFSS of silica-coated fiber was increased by 174 and 85.6%, respectively, and compression strength was increased by 45.7%. This study provides a new approach for improving the interface property and compression strength of high-strength and high-modulus PI-fiber-reinforced composites.

9.
Medicine (Baltimore) ; 103(19): e38106, 2024 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-38728498

RESUMEN

RATIONALE: Recombinant human endostatin (Endostar) is extensively utilized in China for the clinical management of patients with driver gene-negative non-small cell lung cancer (NSCLC) at stage TNM IV. This report describes the case of a lung cancer patient treated exclusively with Endostar maintenance therapy, who experienced a rapid deterioration in respiratory function. PATIENT CONCERNS: The case involved a patient with a pathologically confirmed squamous cell carcinoma of the left lung, treated in our department. Following 1 month of albumin-bound paclitaxel chemotherapy and localized radiotherapy for the left lung lesion, the patient initiated treatment with a single agent, Endostar 30mg, on October 19, 2021. The medication was administered via intravenous infusion over a 7 days. DIAGNOSIS: On October 23, 2021, the patient exhibited symptoms of chest constriction, discomfort, coughing, and sputum production. By October 28, the patient presented with pronounced dyspnea and respiratory distress. An emergency CT scan detected pericardial tamponade and significant deviations in several blood parameters from pretreatment values. INTERVENTIONS: Percardial puncture and catheter drainage were recommended as therapeutic intervention. OUTCOMES: Considering the patient advanced age, the patient and their family opted to refuse this medical procedure, leading to the patient unfortunate demise on November 2, 2021. LESSONS: Medical professionals should remain vigilant for the potential, albeit rare, risk of Endostar inducing acute pericardial tamponade, a severe and potentially fatal complication.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Taponamiento Cardíaco , Endostatinas , Neoplasias Pulmonares , Proteínas Recombinantes , Humanos , Carcinoma de Pulmón de Células no Pequeñas/complicaciones , Endostatinas/uso terapéutico , Neoplasias Pulmonares/complicaciones , Masculino , Taponamiento Cardíaco/etiología , Taponamiento Cardíaco/terapia , Proteínas Recombinantes/uso terapéutico , Proteínas Recombinantes/administración & dosificación , Resultado Fatal , Anciano , Persona de Mediana Edad , Antineoplásicos/efectos adversos , Antineoplásicos/uso terapéutico
10.
Artículo en Inglés | MEDLINE | ID: mdl-38657160

RESUMEN

High-energy-density lithium metal batteries (LMBs) are confronted with crucial concerns of security and a short cycle lifespan caused by the uncontrollable formation of lithium (Li) dendrites. The poor thermal stability and heterogeneous Li deposition of conventional polyolefin separators often cause battery short circuiting and thermal runaway in LMBs. Herein, a novel dual-functional PE composite separator (PI-COOH/PE) coated by carboxyl polyimide (PI) microspheres is fabricated by an etching-acidification method. The three-dimensional (3D) high-temp PI microsphere with rich carboxyl groups on the surface improve the security of LMBs at extremely high temperatures and facilitate the formation of a stable and uniform SEI layer, which contributes to accelerating the Li+ transport and stabilizing the formation of the SEI layer. Consequently, the Li symmetric cell assembled with the (PI-COOH)/PE separator exhibits stable overpotential over 3000 h, and the corresponding Li//NCM811 full cells also show a high-level discharge capacity of 146.6 mAh g-1 at 5 C. Meanwhile, it also demonstrates outstanding cycling stability and thermal safety, which can survive continuously over 160 min at 140 °C (vs 21 min for PE). The above results indicate the (PI-COOH)/PE separator constructed by a low-cost and industrial-friendly strategy simultaneously addresses high-temperature stability and dendrite resistance.

11.
J Affect Disord ; 353: 38-47, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38417715

RESUMEN

PURPOSE: Previous studies have suggested a potential association between gut microbiota and neurological and psychiatric disorders. However, the causal relationship between gut microbiota and cognitive performance remains uncertain. METHODS: A two-sample Mendelian randomization (MR) study used SNPs linked to gut microbiota (n = 18,340) and cognitive performance (n = 257,841) from recent GWAS data. Inverse-variance weighted (IVW), MR Egger, weighted median, simple mode, and weighted mode were employed. Heterogeneity was assessed via Cochran's Q test for IVW. Results were shown with funnel plots. Outliers were detected through leave-one-out method. MR-PRESSO and MR-Egger intercept tests were conducted to address horizontal pleiotropy influence. LIMITATIONS: Limited to European populations, generic level, and potential confounding factors. RESULTS: IVW analysis revealed detrimental effects on cognitive perfmance associated with the presence of genus Blautia (P = 0.013, 0.966[0.940-0.993]), Catenibacterium (P = 0.035, 0.977[0.956-0.998]), Oxalobacter (P = 0.043, 0.979[0.960-0.999]). Roseburia (P < 0.001, 0.935[0.906-0.965]), in particular, remained strongly negatively associated with cognitive performance after Bonferroni correction. Conversely, families including Bacteroidaceae (P = 0.043, 1.040[1.001-1.081]), Rikenellaceae (P = 0.047, 1.026[1.000-1.053]), along with genera including Paraprevotella (P = 0.044, 1.020[1.001-1.039]), Ruminococcus torques group (P = 0.016, 1.062[1.011-1.115]), Bacteroides (P = 0.043, 1.040[1.001-1.081]), Dialister (P = 0.027, 1.039[1.004-1.074]), Paraprevotella (P = 0.044, 1.020[1.001-1.039]) and Ruminococcaceae UCG003 (P = 0.007, 1.040[1.011-1.070]) had a protective effect on cognitive performance. CONCLUSIONS: Our results suggest that interventions targeting specific gut microbiota may offer a promising avenue for improving cognitive function in diseased populations. The practical application of these findings has the potential to enhance cognitive performance, thereby improving overall quality of life.


Asunto(s)
Microbioma Gastrointestinal , Trastornos Mentales , Humanos , Microbioma Gastrointestinal/genética , Análisis de la Aleatorización Mendeliana , Calidad de Vida , Cognición
12.
Polymers (Basel) ; 15(4)2023 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-36850315

RESUMEN

Developing polyimide (PI) fibers with excellent interfacial adhesion and high mechanical properties for the PI fiber-reinforced polymer matrix composites (PFRPs) industry has been challenging. In this work, 4,4'-diamino-(1,1'-biphenyl)-3,3'-diol (HAB) diamine was introduced into the rigid molecular chains, and the high-performance PI fibers, presenting an interfacial shear strength (IFSS) value of 46.33 MPa, tensile strength of 2.62 GPa, and modulus of 100.15 GPa, were successfully manufactured when the content of HAB in mixed diamines was 30 mol %. Fourier transform infrared (FTIR) spectroscopy identified the presence of intermolecular H-bonding interactions, and 2D small-angle X-ray scattering indicated that the introduction of HAB moiety contributed to reducing the radii of microvoids in the fibers, which were considered to be the key factors leading to a significant enhancement in the mechanical properties of the fibers. X-ray photoelectron spectroscopy (XPS) and the static contact angle intuitively illustrated that the synthetic fiber surface contained active hydroxyl groups. The IFSS value of PI fiber/epoxy resin composites (PI/EPs) was 56.47 MPa when the content of HAB reached 70 mol %. Failure morphologies confirmed that the interfacial adhesion of PI/EPs was enhanced owing to the surface activity of PI fibers. Consequently, this study provides an effective strategy to the long-standing problems of high mechanical performances and poor surface activity for traditional PI fibers used in the PFRPs industry.

13.
Radiol Case Rep ; 18(7): 2366-2369, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37179807

RESUMEN

Bevacizumab is widely used in the treatment of colorectal cancer, liver cancer, and other advanced solid tumors because of its multiple targets, no genetic testing and better safety. Globally, the use of bevacizumab in the clinic has been climbing year by year based on several large-scale, multicenter prospective studies. While bevacizumab undeniably has a good clinical safety profile, it has also been associated with adverse effects such as drug-related hypertension and anaphylaxis. In our recent clinical work, we met a female patient with acute aortic coarctation previously treated with multiple cycles of bevacizumab, who was admitted with sudden onset of back pain. Because the patient had just had an enhanced CT of the chest and abdomen a month earlier, no abnormal lesions apparently associated with low back pain were found. So when the patient was seen on this occasion, our clinical diagnosis was first considered to be neuropathic pain, but a further multiphase enhancement CT was done again for further exclusion and the final diagnosis was acute aortic dissection. The patient later died within 1 hour after the chest pain had worsened again while waiting for a surgical blood supply within 72 hours of presentation. The risk of fatal acute aortic dissection is not sufficiently emphasized in the revised instructions for bevacizumab, although the adverse effects associated with aortic dissection and aneurysm are mentioned. Our report is of high practical value in raising clinicians' vigilance and safe management of patients using bevacizumab worldwide.

14.
Dis Markers ; 2022: 2192001, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35845138

RESUMEN

Background: The competing endogenous RNA (CeRNA) network plays important roles in the occurrence and development of colon cancer. This research is aimed at constructing a miRNA-mRNA network associated with exosomes in colon cancer. Methods: We explored the GEO database and then analyzed the RNAs of 722 samples to obtain differentially expressed miRNAs (DEMs) and mRNAs (DEGs) alongside the progress of colon cancer. Next, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of DEM target genes and DEGs were performed. In addition, a miRNA-mRNA network related to exosomes in colon cancer was constructed based on DEMs and DEGs. Finally, the expression of miRNA and mRNA in the network was verified by GEPIA2 on the base of TCGA database. Results: Through our analysis, 19 DEMs (17 up and 2 down) and 1672 DEGs (954 up and 718 down) were screened. The GO and KEGG results show that these DEGs were mainly enriched in ribonucleoprotein complex biogenesis, noncoding RNA metabolic process, cell-substrate junction, cadherin binding, transcription coregulator activity, and regulation of the human T-cell leukemia virus 1 infection-related pathway. Besides, a miRNA-mRNA network, including 4 miRNAs (hsa-miR-623, hsa-miR-320c, hsa-miR-486-5p, and hsa-miR-1290) and 7 mRNAs (GNAI1, CADM1, PGRMC2, etc.), was constructed. Three of these seven mRNAs were downregulated in colon cancer. Ultimately, the GNAI1, CADM1, and PGRMC2 expression levels were verified by TCGA database. Conclusions: This study reveals the network relationship between colon cancer exosome-derived miRNA and targeted mRNA. It deepens our understanding of new molecular mechanisms and pathways that may play a role in the occurrence and metastasis of colon cancer.


Asunto(s)
Neoplasias del Colon , Exosomas , MicroARNs , ARN Largo no Codificante , Molécula 1 de Adhesión Celular/genética , Neoplasias del Colon/genética , Exosomas/genética , Exosomas/metabolismo , Redes Reguladoras de Genes , Humanos , MicroARNs/genética , MicroARNs/metabolismo , ARN Largo no Codificante/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo
15.
J Colloid Interface Sci ; 625: 936-945, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-35777100

RESUMEN

Separators are applied to segregate cathode and anode, and provide ion transport channels in lithium-ion batteries (LIBs). Nevertheless, present commercial polyolefin separators represent high thermal shrinkage and inferior electrolyte wettability, seriously limiting wider development of LIBs. In this work, we prepared zirconia (ZrO2) nanolayer encapsulated polyimide (PI) nanofiber compound separator through in-situ polar adsorption and hydrolysis strategy. The obtained PI/ZrO2 compound separator has superior thermal stability, electrolyte wettability and flame retardance in comparison with polypropylene (PP) separator. The shrinkage ratio of prepared PI/ZrO2 compound separator is 0 even at 300 °C, while the PP separator significantly shrank at 160 °C. Furthermore, the ionic conductivity of PI/ZrO2 separator reaches up to 1.32 mS cm-1, far higher than 0.34 mS cm-1 of PP separator. Besides, the coin batteries of LiNi0.8Co0.1Mn0.1O2 (NCM811)/electrolyte-separator/lithium (Li) assembled with PI/ZrO2 compound separator exhibit enhanced rate performance, high discharge capacity retention rate of 88.3% after 100 cycles at 1C and excellent battery safety performance even at 140 °C. Thus, combined with its advantages, such as preparation, thermostability, electrolyte wettability, electrochemical property and safety, the PI/ZrO2 compound separator exhibits promising prospect in the application of commercial LIBs.

16.
Nat Commun ; 13(1): 885, 2022 02 16.
Artículo en Inglés | MEDLINE | ID: mdl-35173177

RESUMEN

The evergrowing plastic production and the caused concerns of plastic waste accumulation have stimulated the need for waste plastic chemical recycling/valorization. Current methods suffer from harsh reaction conditions and long reaction time. Herein we demonstrate a non-thermal plasma-assisted method for rapid hydrogenolysis of polystyrene (PS) at ambient temperature and atmospheric pressure, generating high yield (>40 wt%) of C1-C3 hydrocarbons and ethylene being the dominant gas product (Selectivity of ethylene, SC2H4 > 70%) within ~10 min. The fast reaction kinetics is attributed to highly active hydrogen plasma, which can effectively break bonds in polymer and initiate hydrogenolysis under mild condition. Efficient hydrogenolysis of post-consumer PS materials using this method is also demonstrated, suggesting a promising approach for fast retrieval of small molecular hydrocarbon modules from plastic materials as well as a good capability to process waste plastics in complicated conditions.

17.
Macromol Rapid Commun ; 32(4): 384-9, 2011 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-21433188

RESUMEN

A functional polyimide, hexafluoroisopropyl bis(phthalic dianhydride)/3,6-diaminocarbazole (6FDA/DAC), in which DAC serves as electron donor and 6FDA as electron acceptor, has been synthesized in our present work. Electrical characterization results on the sandwiched polyimide memory device (ITO/Thin polyimide Layer/Au) indicate that the polyimide possesses electrical bistability and the device exhibits two accessible conductivity states, which can be reversibly switched from the low-conductivity (OFF) state to the high-conductivity (ON) state with an ON/OFF current ratio of about 10(4). Different from the widely reported write-once-read-many-times (WORM) effects, the device with the 6FDA/DAC polyimide as the active layer shows dynamic random access memory (DRAM) behavior. The ON state of the device was lost immediately after removal of the applied voltage, while by applying a constant bias (e.g., 3 V) the ON state can be electrically sustained. The roles of donor and acceptor components in the polyimide main chain were elucidated through molecular simulation.


Asunto(s)
Conductividad Eléctrica , Resinas Sintéticas/química , Transporte de Electrón , Estructura Molecular , Propiedades de Superficie
18.
J Colloid Interface Sci ; 583: 470-486, 2021 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-33011414

RESUMEN

Temperature/pH dual-stimuli-responsive phase-change microcapsules (Dual-SR-MEPCM) were designed that can form the basis of smart drug delivery systems. They employed n-eicosane as a phase change material (PCM) microencapsulated in an acrylate-functionalized silica shell via emulsion-templated interfacial polycondensation. A poly(N-isopropylacrylamide-co-acrylate acid) functional layer was then fabricated on the surface of the silica shell through surfactant-assisted radical polymerization. The combination of phase-change microcapsules and stimuli-responsive material results in a system that synchronously implements thermal self-regulation by its PCM core together with controllable drug release through its polymeric functional layer. The resultant Dual-SR-MEPCM exhibits regularly spherical morphology, uniform particle-size distribution and well-defined core-shell microstructure, which indicates successful construction according to our design principle. This system has been further evaluated for multipurpose applications in thermal regulation and drug delivery with independent temperature and pH triggering. The Dual-SR-MEPCM not only shows a high thermal energy-storage capacity of over 160 J/g, but also good anti-leakage performance, thermal cycle stability and high-temperature shape stability. Our studies also reveal independent stimuli-responsive behaviors for temperature and pH when using bovine serum albumin and doxorubicin hydrochloride as model drugs. All of these features indicate that the Dual-SR-MEPCM designed in this study can serve as a promising candidate for smart drug delivery systems, with great potential for future multipurpose applications in advanced pharmaceutical areas.


Asunto(s)
Doxorrubicina , Sistemas de Liberación de Medicamentos , Cápsulas , Liberación de Fármacos , Concentración de Iones de Hidrógeno , Temperatura
19.
ACS Appl Mater Interfaces ; 13(46): 55292-55298, 2021 Nov 24.
Artículo en Inglés | MEDLINE | ID: mdl-34780157

RESUMEN

Hydrogen storage presents a major difficulty in the development of hydrogen economy. Herein, we report a new electrochemical ethylamine/acetonitrile redox method for hydrogen storage with an 8.9 wt % theoretical storage capacity under ambient conditions. This method exhibits low onset overpotentials of 0.19 V in CH3CH2NH2 dehydrogenation to CH3CN and 0.09 V in CH3CN hydrogenation to CH3CH2NH2 using commercial Pt black catalyst. By assembling a full cell that couples CH3CH2NH2/CH3CN redox reactions with hydrogen evolution and oxidation reactions, we demonstrate a complete hydrogen storage cycle at fast rates, with only 52.5 kJ/mol energy consumption for H2 uptake and release at a rate of 1 L/m2·h. This method provides a viable hydrogen storage strategy that meets the 2025 Department of Energy onboard hydrogen storage target.

20.
Nanomaterials (Basel) ; 11(11)2021 Nov 12.
Artículo en Inglés | MEDLINE | ID: mdl-34835800

RESUMEN

Electromagnetic (EM) and infrared (IR) stealth play an important role in the development of military technology and the defense industry. This study focused on developing a new type of multifunctional composite film based on polyimide (PI)/graphene/Fe3O4 hybrid aerogel and polyethylene glycol (PEG) as a phase change material (PCM) for EM and IR bi-stealth applications. The composite films were successfully fabricated by constructing a series of PI-based hybrid aerogels containing different contents of graphene nanosheets and Fe3O4 nanoparticles through prepolymerizaton, film casting, freeze-drying, and thermal imidization, followed by loading molten PEG through vacuum impregnation. The construction of PI/graphene/Fe3O4 hybrid aerogel films provides a robust, flexible, and microwave-absorption-functionalized support material for PEG. The resultant multifunctional composite films not only exhibit high microwave absorption effectiveness across a broad frequency range, but also show a good ability to implement thermal management and temperature regulation under a high latent-heat capacity of over 158 J/g. Most of all, the multifunctional composite films present a wideband absorption capability at 7.0-16.5 GHz and a minimum reflection loss of -38.5 dB. This results in excellent EM and IR bi-stealth performance through the effective wideband microwave absorption of graphene/Fe3O4 component and the thermal buffer of PEG. This study offers a new strategy for the design and development of high-performance and lightweight EM-IR bi-stealth materials to meet the requirement of stealth and camouflage applications in military equipment and defense engineering.

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