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1.
Chem Rev ; 123(2): 701-735, 2023 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-36577085

RESUMEN

Self-healing materials open new prospects for more sustainable technologies with improved material performance and devices' longevity. We present an overview of the recent developments in the field of intrinsically self-healing polymers, the broad class of materials based mostly on polymers with dynamic covalent and noncovalent bonds. We describe the current models of self-healing mechanisms and discuss several examples of systems with different types of dynamic bonds, from various hydrogen bonds to dynamic covalent bonds. The recent advances indicate that the most intriguing results are obtained on the systems that have combined different types of dynamic bonds. These materials demonstrate high toughness along with a relatively fast self-healing rate. There is a clear trade-off relationship between the rate of self-healing and mechanical modulus of the materials, and we propose design principles of polymers toward surpassing this trade-off. We also discuss various applications of intrinsically self-healing polymers in different technologies and summarize the current challenges in the field. This review intends to provide guidance for the design of intrinsic self-healing polymers with required properties.

2.
Angew Chem Int Ed Engl ; 62(47): e202310989, 2023 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-37783669

RESUMEN

Despite intensive research on sustainable elastomers, achieving elastic vitrimers with significantly improved mechanical properties and recyclability remains a scientific challenge. Herein, inspired by the classical elasticity theory, we present a design principle for ultra-tough and highly recyclable elastic vitrimers with a defined network constructed by chemically crosslinking the pre-synthesized disulfide-containing polydimethylsiloxane (PDMS) chains with tetra-arm polyethylene glycol (PEG). The defined network is achieved by the reduced dangling short chains and the relatively uniform molecular weight of network strands. Such elastic vitrimers with the defined network, i.e., PDMS-disulfide-D, exhibit significantly improved mechanical performance than random analogous, previously reported PDMS vitrimers, and even commercial silicone-based thermosets. Moreover, unlike the vitrimers with random network that show obvious loss in mechanical properties after recycling, those with the defined network enable excellent thermal recyclability. The PDMS-disulfide-D also deliver comparable electrochemical signals if utilized as substrates for electromyography sensors after the recycling. The multiple relaxation processes are revealed via a unique physical approach. Multiple techniques are also applied to unravel the microscopic mechanism of the excellent mechanical performance and recyclability of such defined network.

3.
Langmuir ; 38(32): 9751-9759, 2022 08 16.
Artículo en Inglés | MEDLINE | ID: mdl-35921602

RESUMEN

Interfacial properties of polymeric materials are significantly influenced by their architectural structures and spatial features, while such a study of topologically interesting macromolecules is rarely reported. In this work, we reported, for the first time, the interfacial behavior of catenated poly(l-lactide) (C-PLA) at the air-water interface and compared it with its linear analogue (L-PLA). The isotherms of surface pressure-area per repeating unit showed significant interfacial behavioral differences between the two polymers with different topologies. Isobaric creep experiments and compression-expansion cycles also showed that C-PLA demonstrated higher stability at the air-water interface. Interestingly, when the films at different surface pressures were transferred via the Langmuir-Blodgett method, successive atomic force microscopy imaging displayed distinct nanomorphologies, in which the surface of C-PLA exhibited nanofibrous structures, while that of the L-PLA revealed a smoother topology with less fiber-like structures.


Asunto(s)
Aire , Agua , Microscopía de Fuerza Atómica , Poliésteres/química , Polímeros/química , Propiedades de Superficie , Agua/química
4.
Soft Matter ; 16(2): 390-401, 2020 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-31840152

RESUMEN

Recent findings that the association bond lifetimes τα* in associating polymers diverge from their supramolecular network relaxation times τc challenge past theories. The bond lifetime renormalization proposed by Rubinstein and coworkers [Stukalin et al., Macromolecules, 2013, 46, 7525] provides a promising explanation. To examine systematically its applicability, we employ shear rheology and dielectric spectroscopy to study telechelic associating polymers with different main chain (polypropylene glycol and polydimethylsiloxane), molecular weight (below entanglement molecular weight) and end groups (amide, and carboxylic acid) which form dimeric associations by hydrogen bonding. The separation between τc (probed by rheology) and τα* (probed by dielectric spectroscopy) strongly increases with chain length as qualitatively predicted by the model. However, to describe the increase quantitatively, a transition from Rouse to reptation dynamics must be assumed. This suggests that dynamics of super-chains must be considered to properly describe the transient network.

5.
Chemistry ; 25(47): 10976-10994, 2019 Aug 22.
Artículo en Inglés | MEDLINE | ID: mdl-31041811

RESUMEN

Silicon (Si) is a promising candidate for high-capacity anode materials owing to its high theoretical capacity (3579 mAh g-1 ), low working voltage, and wide natural abundance, although its huge volume variation during charge/discharge processes always results in a short cycling life. Polymer binders play a vital role in improving the cycling performance of Si-based anodes, although traditional polyvinylidene difluoride cannot fulfil the requirements owing to its weak van der Waals forces with the Si surface. Recently, polymer binders constructed by dynamic bonds have been developed, which are reported to allow high-energy-density electrodes with improved electrochemical performance. With dynamic bonds including hydrogen bonding, ionic bonding, and host-guest interactions, these polymer binders possess self-healing capabilities and enhanced mechanical performance, achieving a tremendous advance in addressing the capacity fading of Si-based anodes. In this review, we will summarize the research progress of polymer binders constructed with dynamic bonds, and the challenges for their real applications in advanced Li-ion batteries will also be discussed.

6.
Small ; 14(22): e1800115, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-29700977

RESUMEN

Poly(ε-caprolactone) (PCL)-based nanomaterials, such as nanoparticles and liposomes, have exhibited great potential as controlled release systems, but the difficulties in large-scale fabrication limit their practical applications. Among the various methods being developed to fabricate polymer nanosheets (PNSs) for different applications, such as Langmuir-Blodgett technique and layer-by-layer assembly, are very effort consuming, and only a few PNSs can be obtained. In this paper, poly(ε-caprolactone)-based PNSs with adjustable thickness are obtained in large quantity by simple water exposure of multilayer polymer films, which are fabricated via a layer multiplying coextrusion method. The PNS is also demonstrated as a novel controlled guest release system, in which release kinetics are adjustable by the nanosheet thickness, pH values of the media, and the presence of protecting layers. Theoretical simulations, including Korsmeyer-Peppas model and Finite-element analysis, are also employed to discern the observed guest-release mechanisms.

7.
Environ Microbiol ; 19(2): 566-583, 2017 02.
Artículo en Inglés | MEDLINE | ID: mdl-27554678

RESUMEN

Ganoderma lucidum is one of the most important medicinal fungi, but the lack of basic study on the fungus has hindered the further development of its value. To investigate the roles of the redox system in G. lucidum, acetic acid (HAc) was applied as a reactive oxygen species (ROS) stress inducer, and hydrogen-rich water (HRW) was used to relieve the ROS stress in this study. Our results demonstrate that the treatment of 5% HRW significantly decreased the ROS content, maintained biomass and polar growth morphology of mycelium, and decreased secondary metabolism under HAc-induced oxidative stress. Furthermore, the roles of HRW were largely dependent on restoring the glutathione system under HAc stress in G. lucidum. To provide further evidence, we used two glutathione peroxidase (GPX)-defective strains, the gpxi strain, the mercaptosuccinic acid (MS, a GPX inhibitor)-treated wide-type (WT) strain, and gpx overexpression strains for further research. The results show that HRW was unable to relieve the HAc-induced ROS overproduction, decreased biomass, mycelium morphology change and increased secondary metabolism biosynthesis in the absence of GPX function. The gpx overexpression strains exhibited resistance to HAc-induced oxidative stress. Thus, we propose that HRW regulates morphology, growth and secondary metabolism via glutathione peroxidase under HAc stress in the fungus G. lucidum. Furthermore, our research also provides a method to study the ROS system in other fungi.


Asunto(s)
Glutatión Peroxidasa/metabolismo , Estrés Oxidativo , Especies Reactivas de Oxígeno/metabolismo , Reishi/enzimología , Agua/química , Regulación Enzimológica de la Expresión Génica , Regulación Fúngica de la Expresión Génica , Glutatión/metabolismo , Hidrógeno , Micelio/metabolismo , Oxidación-Reducción , Reishi/metabolismo , Metabolismo Secundario
8.
Appl Environ Microbiol ; 83(20)2017 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-28802268

RESUMEN

Putrescine is an important polyamine that participates in a variety of stress responses. Ornithine decarboxylase (ODC) is a key enzyme that catalyzes the biosynthesis of putrescine. A homolog of the gene encoding ODC was cloned from Ganoderma lucidum In the ODC-silenced strains, the transcript levels of the ODC gene and the putrescine content were significantly decreased. The ODC-silenced strains were more sensitive to oxidative stress. The content of ganoderic acid was increased by approximately 43 to 46% in the ODC-silenced strains. The content of ganoderic acid could be recovered after the addition of exogenous putrescine. Additionally, the content of reactive oxygen species (ROS) was significantly increased by approximately 1.3-fold in the ODC-silenced strains. The ROS content was significantly reduced after the addition of exogenous putrescine. The gene transcript levels and the activities of four major antioxidant enzymes were measured to further explore the effect of putrescine on the intracellular ROS levels. Further studies showed that the effect of the ODC-mediated production of putrescine on ROS might be a factor influencing the biosynthesis of ganoderic acid. Our study reports the role of putrescine in large basidiomycetes, providing a basis for future studies of the physiological functions of putrescine in microbes.IMPORTANCE It is well known that ODC and the ODC-mediated production of putrescine play an important role in resisting various environmental stresses, but there are few reports regarding the mechanisms underlying the effect of putrescine on secondary metabolism in microorganisms, particularly in fungi. G. lucidum is gradually becoming a model organism for studying environmental regulation and metabolism. In this study, a homolog of the gene encoding ODC was cloned in Ganoderma lucidum We found that the transcript level of the ODC gene and the content of putrescine were significantly decreased in the ODC-silenced strains. The content of ganoderic acid was significantly increased in the ODC-silenced strains. Further studies showed that the effect of the ODC-mediated production of putrescine on ROS might be a factor influencing the biosynthesis of ganoderic acid. Our study reports the role of putrescine in large basidiomycetes, providing a basis for future studies of the physiological functions of putrescine in microbes.


Asunto(s)
Proteínas Fúngicas/metabolismo , Ganoderma/metabolismo , Ornitina Descarboxilasa/metabolismo , Putrescina/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Triterpenos/metabolismo , Proteínas Fúngicas/genética , Ganoderma/enzimología , Ganoderma/genética , Ornitina Descarboxilasa/genética , Estrés Oxidativo
9.
Appl Environ Microbiol ; 82(14): 4112-4125, 2016 07 15.
Artículo en Inglés | MEDLINE | ID: mdl-27129961

RESUMEN

UNLABELLED: Heat stress (HS) influences the growth and development of organisms. Thus, a comprehensive understanding of how organisms sense HS and respond to it is required. Ganoderma lucidum, a higher basidiomycete with bioactive secondary metabolites, has become a potential model system due to the complete sequencing of its genome, transgenic systems, and reliable reverse genetic tools. In this study, we found that HS inhibited mycelium growth, reduced hyphal branching, and induced the accumulation of ganoderic acid biosynthesis and heat shock proteins (HSPs) in G. lucidum Our data showed that HS induced a significant increase in cytosolic Ca(2+) concentration. Further evidence showed that Ca(2+) might be a factor in the HS-mediated regulation of hyphal branching, ganoderic acid (GA) biosynthesis, and the accumulation of HSPs. Our results further showed that the calcium-permeable channel gene (cch)-silenced and phosphoinositide-specific phospholipase gene (plc)-silenced strains reduced the HS-induced increase in HSP expression compared with that observed for the wild type (WT). This study demonstrates that cytosolic Ca(2+) participates in heat shock signal transduction and regulates downstream events in filamentous fungi. IMPORTANCE: Ganoderma lucidum, a higher basidiomycete with bioactive secondary metabolites, has become a potential model system for evaluating how environmental factors regulate the development and secondary metabolism of basidiomycetes. Heat stress (HS) is an important environmental challenge. In this study, we found that HS inhibited mycelium growth, reduced hyphal branching, and induced HSP expression and ganoderic acid biosynthesis in G. lucidum Further evidence showed that Ca(2+) might be a factor in the HS-mediated regulation of hyphal branching, GA biosynthesis, and the accumulation of HSPs. This study demonstrates that cytosolic Ca(2+) participates in heat shock signal transduction and regulates downstream events in filamentous fungi. Our research offers a new way to understand the mechanism underlying the physiological and metabolic responses to other environmental factors in G. lucidum This research may also provide the basis for heat shock signal transduction studies of other fungi.


Asunto(s)
Calcio/metabolismo , Proteínas de Choque Térmico/biosíntesis , Calor , Micelio/efectos de la radiación , Reishi/efectos de la radiación , Estrés Fisiológico , Triterpenos/metabolismo , Señalización del Calcio , Citosol/química , Micelio/crecimiento & desarrollo , Micelio/metabolismo , Reishi/crecimiento & desarrollo , Reishi/metabolismo
10.
Angew Chem Int Ed Engl ; 54(17): 5127-31, 2015 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-25728998

RESUMEN

A synthetic strategy is reported for the production of a trefoil knotted polymer from a copper(I)-templated helical knot precursor through ring expansion. The expected changes in the properties of the knotted polymer compared to a linear analogue, for example, reduced hydrodynamic radius and lower intrinsic viscosity, together with an atomic force microscopy (AFM) image of individual molecular knots, confirmed the formation of the resulting trefoil knotted polymer. The strategies employed here could be utilized to enrich the variety of available polymers with new architectures.


Asunto(s)
Polímeros/química , Cobre/química , Espectroscopía de Resonancia Magnética , Microscopía de Fuerza Atómica , Polímeros/síntesis química , Viscosidad
11.
Tumour Biol ; 35(4): 3223-8, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24272086

RESUMEN

In clinical practice, we found that some primary gastrointestinal mucosa-associated lymphoid tissue (MALT) lymphoma had different prognosis. This study aimed to explore the role of IGH rearrangement, p53 and ATM gene variations in the assessment of prognosis in primary gastrointestinal MALT lymphoma. In 50 cases of primary gastrointestinal MALT lymphoma (1) IGH arrangement was found in 59.5% of patients with primary gastrointestinal MALT lymphoma; IGH arrangement was found in 48.4% of patients with primary gastrointestinal MALT lymphoma at stage I-II and in 90.9% of patients at stage III-IV (χ(2) = 6.093, p < 0.05). Average survival time in patients with IGH rearrangement was 16.39 months, being shorter than that in patients with non-IGH rearrangement (38.13 months) (t = 3.239, p < 0.01). (2) p53 gene deletion was found in 31.0% of patients with primary gastrointestinal MALT lymphoma; p53 gene deletion was found in 22.6 % of patients with primary gastrointestinal MALT lymphoma at stage I-II and in 54.5% of patients at stage III-IV (χ(2) = 3.882, p < 0.05). Average survival time in patients with p53 gene deletion was 8.0 months, being shorter than that of patients with normal p53 gene (32.81 months) (t = 3.609, p < 0.01). (3) ATM gene deletion was found in 23.8% of patients with primary gastrointestinal MALT lymphoma; ATM gene deletion was found in 16.1 % of patients with primary gastrointestinal MALT lymphoma at stage I-II and in 45.5% of patients at stage III-IV (χ(2) = 3.849, p < 0.05). Average survival time in patients with ATM gene deletion was 6.10 months, which is shorter than that of patients with normal ATM gene (31.71 months) (t = 3.503, p < 0.01). (4) IGH rearrangement, p53 and ATM gene deletion were no correlation with tumor location. (5) Average survival time in primary gastrointestinal MALT lymphoma patients of non-gene or single gene change was 33.42 months, which is longer than that of patients with multiple genes change (6.67 months) (t = 4.013,p < 0.01). There was a high incidence of IGH rearrangement or p53 and ATM gene deletion in patients at stage III-IV. The average survival time was shorter in these patients. Average survival time in primary gastrointestinal MALT lymphoma patients with multiple genes abnormalities was shorter than that in non-gene or single gene change patients. IGH rearrangement, p53 and ATM gene deletion may play a synergistic role in the occurrence and development of the primary gastrointestinal MALT lymphoma. Patients with multiple genes abnormalities had poor prognosis, and they should be advised early united chemotherapy.


Asunto(s)
Neoplasias Gastrointestinales/genética , Regulación Neoplásica de la Expresión Génica , Linfoma de Células B de la Zona Marginal/genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Proteínas de la Ataxia Telangiectasia Mutada/genética , Femenino , Neoplasias Gastrointestinales/microbiología , Neoplasias Gastrointestinales/patología , Eliminación de Gen , Genes p53 , Helicobacter pylori/aislamiento & purificación , Humanos , Hibridación Fluorescente in Situ , Linfoma de Células B de la Zona Marginal/microbiología , Linfoma de Células B de la Zona Marginal/patología , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias
12.
ACS Mater Au ; 4(2): 185-194, 2024 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-38496049

RESUMEN

Elastic vitrimers, i.e., elastic polymers with associative dynamic covalent bonds, can afford elastomers with recyclability while maintaining their thermal and chemical stability. Herein, we report a series of boronic ester-based vitrimers with tunable mechanical properties and recyclability by varying the substitute groups of boronic acid in polymer networks. The dynamic polymer networks are formed by reacting diol-containing tetra-arm poly(amidoamine) with boronic acid-terminated tetra-arm poly(ethylene glycol), which possesses different substituents adjacent to boronic acid moieties. Varying the substituent adjacent to the boronic ester unit will significantly affect the binding strength of the boronic ester, therefore affecting their dynamics and mechanical performance. The electron-withdrawing substituents noticeably suppress the dynamics of boronic ester exchange and increase the activation energy and relaxation time while enhancing the mechanical strength of the resulting elastic vitrimers. On the other hand, the presence of electron-rich substituent affords relatively reduced glass transition temperature (Tg), faster relaxation, and prominent recyclability and malleability at lower temperatures. The developed pathway will guide the rational design of elastomers with well-tunable dynamics and processabilities.

13.
ACS Appl Mater Interfaces ; 16(10): 12374-12384, 2024 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-38414436

RESUMEN

Metallic lithium (Li) is considered as the "Holy Grail" anode material for next-generation energy storage systems due to its extremely high theoretical capacity and low electrochemical potential. Before the commercialization of the Li electrode, dendritic Li growth and the unstable solid electrolyte interphase layer should be conquered. Herein, a hybrid covalent adaptable polymer network (HCAPN) is prepared via the random copolymerization of poly(ethylene glycol) methyl ether methacrylate and -acetoacetoxyethyl methacrylate, followed by chemical cross-linking with polyethylenimine (PEI) and amine-modified silicon dioxide (SiO2). Such a hybrid network, where PEI and amine-modified SiO2 formed a vinylogous urethane-based dynamic covalent bond with the copolymer, respectively, shows improved mechanical properties, solvent resistance, and excellent healability/recyclability. As the protecting layer on the Li electrode, the assembled HCAPN@Li||HCAPN@Li symmetric cell shows a long cycle life of 800 h with low overpotential at a current density of 1 mA cm-2, and superior electrochemical performance can be achieved in the HCAPN@Li||LiFePO4 full cell (capacity retention of 77% over 400 cycles at 1.5 C) and HCAPN@Li||NCM811 cell (capacity retention of 79% after 300 cycles). Surface morphology analysis is also performed for physical insight into their role as protecting layer. This work provides a new perspective for constructing a hybrid dynamic covalent network-based polymer protecting layer for inhibiting Li dendrite growth.

14.
Mater Horiz ; 11(4): 969-977, 2024 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-38053446

RESUMEN

Elastomers play a vital role in many forthcoming advanced technologies in which their adhesive properties determine materials' interface performance. Despite great success in improving the adhesive properties of elastomers, permanent adhesives tend to stick to the surfaces prematurely or result in poor contact depending on the installation method. Thus, elastomers with on-demand adhesion that is not limited to being triggered by UV light or heat, which may not be practical for scenarios that do not allow an additional external source, provide a solution to various challenges in conventional adhesive elastomers. Herein, we report a novel, ready-to-use, ultra high-strength, ductile adhesive elastomer with an on-demand adhesion feature that can be easily triggered by a compression force. The precursor is mainly composed of a capsule-separated, two-component curing system. After a force-trigger and curing process, the ductile adhesive elastomer exhibits a peel strength and a lap shear strength of 1.2 × 104 N m-1 and 7.8 × 103 kPa, respectively, which exceed the reported values for advanced ductile adhesive elastomers. The ultra-high adhesion force is attributed to the excellent surface contact of the liquid-like precursor and to the high elastic modulus of the cured elastomer that is reinforced by a two-phase design. Incorporation of such on-demand adhesion into an elastomer enables a controlled delay between installation and curing so that these can take place under their individual ideal conditions, effectively reducing the energy cost, preventing failures, and improving installation processes.

15.
ACS Nano ; 18(1): 1226-1236, 2024 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-38153997

RESUMEN

Dielectric elastomer transducers (DETs), with a dielectric elastomer (DE) film sandwiched between two compliant electrodes, are highly sought after in the fields of soft robotics, energy harvesting, and human-machine interaction. To achieve a high-performance DET, it is essential to develop electrodes with high conductivity, strain-insensitive resistance, and adaptability. Herein, we design an electrode (Supra-LMNs) based on multiple dynamic bond cross-linked supramolecular networks (Ns) and liquid metal (LM), which realizes high conductivity (up to 16,000 S cm-1), negligible resistance changes at high strain (1.3-fold increase at 1000% strain), instantaneous self-healability at ambient temperature, and rapid recycling. The conductive pathway can be activated through simple friction by transmitting stress through the silver nanowires (AgNWs) and cross-linking sites of LM particles. This method is especially attractive for printing circuits on flexible substrates, especially DE films. Utilized as dielectric elastomer generator (DEG) electrodes, it reduces the charge loss by 3 orders of magnitude and achieves high generating energy density and energy conversion efficiency on a low-resistance load. Additionally, serving as sensor (DES) and actuator (DEA) electrodes, it enables a highly sensitive sensing capability and complex interaction.

16.
Mater Horiz ; 10(8): 2868-2875, 2023 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-37403693

RESUMEN

The structural design of self-healing materials determines the ultimate performance of the product that can be used in a wide range of applications. Incorporating intrinsic self-healing moieties into puncture-resistant materials could significantly improve the failure resistance and product longevity, since their rapidly rebuilt bonds will provide additional recovery force to resist the external force. Herein, we present a series of tailored urea-modified poly(dimethylsiloxane)-based self-healing polymers (U-PDMS-SPs) that exhibit excellent puncture-resistant properties, fast autonomous self-healing, multi-cycle adhesion capabilities, and well-tunable mechanical properties. Controlling the composition of chemical and physical cross-links enables the U-PDMS-SPs to have an extensibility of 528% and a toughness of 0.6 MJ m-3. U-PDMS-SPs exhibit fast autonomous self-healability with 25% strain recovery within 2 minutes of healing, and over 90% toughness recovery after 16 hours. We further demonstrate its puncture-resistant properties under the ASTM D5748 standard with an unbreakable feature. Furthermore, the multi-cycle adhesive properties of U-PDMS-SPs are also revealed. High puncture resistance (>327 mJ) and facile adhesion with rapid autonomous self-healability will have a broad impact on the design of adhesives, roofing materials, and many other functional materials with enhanced longevity.

17.
ACS Appl Mater Interfaces ; 15(19): 23765-23776, 2023 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-37158416

RESUMEN

Lithium (Li) metal is a highly promising anode material for next-generation high-energy-density batteries, while Li dendrite growth and the unstable solid electrolyte interphase layer inhibit its commercialization. Herein, a chemically grafted hybrid dynamic network (CHDN) is rationally designed and synthesized by the 4,4'-thiobisbenzenamine cross-linked poly(poly(ethylene glycol) methyl ether methacrylate-r-glycidyl methacrylate) and (3-glycidyloxypropyl) trimethoxysilane-functionalized SiO2 nanoparticles, which is utilized as a protective layer and hybrid solid-state electrolyte (HSE) for stable Li-metal batteries. The presence of a dynamic exchangeable disulfide affords self-heability and recyclability, and the chemical attachment between SiO2 nanoparticles and the polymer matrix enables the homogeneous distribution of inorganic fillers and mechanical robustness. With integrated flexibility, fast segmental dynamics, and autonomous adaptability, the as-prepared CHDN-based protective layer enables superior electrochemical performance in half cells and full cells (capacity retention of 83.7% over 400 cycles for the CHDN@Li/LiFePO4 cell at 1 C). Furthermore, benefiting from intimate electrode/electrolyte interfacial contact, CHDN-based solid-state cells deliver excellent electrochemical performance (capacity retention of 89.5% over 500 cycles for the Li/HSE/LiFePO4 cell at 0.5 C). In addition, the Li/HSE/LiFePO4 pouch cell exhibits superior safety, even exposing various physical damage conditions. This work thereby provides a fresh insight into a rational design principle for dynamic network-based protective layers and solid-state electrolytes for battery applications.

18.
Mater Horiz ; 10(9): 3360-3368, 2023 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-37482885

RESUMEN

Plastic represents an essential material in our society; however, a major imbalance between their high production and end-of-life management is leading to unrecovered energy, economic hardship, and a high carbon footprint. The adoption of plastic recycling has been limited, mainly due to the difficulty of recycling mixed plastics. Here, we report a versatile organocatalyst for selective glycolysis of diverse consumer plastics and their mixed waste streams into valuable chemicals. The developed organocatalyst selectively deconstructs condensation polymers at a specific temperature, and additives or other polymers such as polyolefin or cellulose can be readily separated from the mixed plastics, providing a chemical recycling path for many existing mixed plastics today. The Life Cycle Assessment indicates that the production of various condensation polymers from the deconstructed monomers will result in a significant reduction in greenhouse gas emissions and energy input, opening a new paradigm of plastic circularity toward a net-zero carbon society.

19.
ACS Nano ; 16(3): 4746-4755, 2022 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-35234439

RESUMEN

Incorporation of dynamic (reversible) bonds within polymer structure enables properties such as self-healing, shape transformation, and recyclability. These dynamic bonds, sometimes refer as stickers, can form clusters by phase-segregation from the polymer matrix. These systems can exhibit interesting viscoelastic properties with an unusually high and extremely long rubbery plateau. Understanding how viscoelastic properties of these materials are controlled by the hierarchical structure is crucial for engineering of recyclable materials for various future applications. Here we studied such systems made from short telechelic polydimethylsiloxane chains by employing a broad range of experimental techniques. We demonstrate that formation of a percolated network of interfacial layers surrounding clusters enhances mechanical modulus in these phase-separated systems, whereas single chain hopping between the clusters results in macroscopic flow. On the basis of the results, we formulated a general scenario describing viscoelastic properties of phase-separated dynamic polymers, which will foster development of recyclable materials with tunable rheological properties.

20.
ACS Appl Mater Interfaces ; 14(22): 26014-26023, 2022 Jun 08.
Artículo en Inglés | MEDLINE | ID: mdl-35608943

RESUMEN

Although numerous studies on polymeric protective films to stabilize lithium (Li)-metal electrodes have been reported, the construction of self-healing polymers that enables the long-term operation of Li-metal batteries (LMBs) at relatively low temperatures has rarely been demonstrated. Herein, a highly stretchable, autonomous self-healable, and ionic-conducting polymer network (SHIPN) is synthesized as an efficient protective film for LMBs. The network backbone, synthesized from copolymerization of poly(ethylene glycol)-mono-methacrylate (PEGMMA) and 2-[[(butylamino)carbonyl]oxy]ethyl acrylate (BCOE), is chemically cross-linked via diisocyanate. With SHIPN-modified electrodes, enhanced electrochemical performance can be achieved in Li/Cu, Li/Li, and Li/LiFePO4 (Li/LFP) cells. The SHIPN@Li/LFP cell delivers a capacity retention of 85.6% after 500 cycles at 5 °C, resulting from the low-temperature self-healability of SHIPN. In full cells with a high-mass-loading LFP cathode (∼17 mg cm-2), the capacity retention is at least 300% higher than that with a bare Li electrode. Further physical characterizations of electrodes confirm the effect of SHIPN in enhancing the interfacial stability and suppressing Li dendrite growth. Our results will provide insights into rationally designing soft and hybrid materials toward stable LMBs at different temperatures.

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