Blend based polymer nanocomposites, comprising Janus nanoparticles at their polymer/polymer interface, were analytically/experimentally evaluated. The modeling procedure was performed in two stages: first, modeling of...Blend based polymer nanocomposites, comprising Janus nanoparticles at their polymer/polymer interface, were analytically/experimentally evaluated. The modeling procedure was performed in two stages: first, modeling of polymer/polymer interface region comprising Janus nanoparticles and second, modeling of the entire systems as a function of the variation of the blend morphology.In the first stage, the modeling procedure was performed based on the development of the model proposed by Ji et al. and in the second stage, the fundamental of Kolarik's model was used in order to propose a developed and more practical model. It was shown that Janus nanoparticles may form dual polymer/particle interphase at polymer/polymer interface which can drastically affect the final mechanical properties of the system. Comparing the results of tensile tests imposed on different prepared samples with the predictions of the model proved its accuracy and reliability(error < 9%).展开更多
In this work,a unique model is proposed for predicting the tensile strength of binary polymer blends considering the effects of polymer/polymer interface and the morphological variation of the system.The modeling was ...In this work,a unique model is proposed for predicting the tensile strength of binary polymer blends considering the effects of polymer/polymer interface and the morphological variation of the system.The modeling was performed based on the combination of analytical and artificial neural network (ANN) modeling methods.For the analytical part,Kolarik’s model was developed in accordance with the system requirements and ANN was simultaneously involved in order to interpret some effective model parameters using the tensile test result of an actual sample (e.g.the yield strength and thickness of the interface,etc.).Furthermore,the model accuracy was evaluated by comparing the tensile test results of differently preparediPP/PA and PS/PMMA blend samples and also some other data from literature with the model predictions.It was revealed that the designed ANN perfectly elevates the capability of the analytical section in order to predict the tensile strength of binary polymer blends with different compositions (prediction error <10%).展开更多
Composite polymer electrolytes(CPEs)offer a promising solution for all-solid-state lithium-metal batteries(ASSLMBs).However,conventional nanofillers with Lewis-acid-base surfaces make limited contribution to improving...Composite polymer electrolytes(CPEs)offer a promising solution for all-solid-state lithium-metal batteries(ASSLMBs).However,conventional nanofillers with Lewis-acid-base surfaces make limited contribution to improving the overall performance of CPEs due to their difficulty in achieving robust electrochemical and mechanical interfaces simultaneously.Here,by regulating the surface charge characteristics of halloysite nanotube(HNT),we propose a concept of lithium-ion dynamic interface(Li^(+)-DI)engineering in nano-charged CPE(NCCPE).Results show that the surface charge characteristics of HNTs fundamentally change the Li^(+)-DI,and thereof the mechanical and ion-conduction behaviors of the NCCPEs.Particularly,the HNTs with positively charged surface(HNTs+)lead to a higher Li^(+)transference number(0.86)than that of HNTs-(0.73),but a lower toughness(102.13 MJ m^(-3)for HNTs+and 159.69 MJ m^(-3)for HNTs-).Meanwhile,a strong interface compatibilization effect by Li^(+)is observed for especially the HNTs+-involved Li^(+)-DI,which improves the toughness by 2000%compared with the control.Moreover,HNTs+are more effective to weaken the Li^(+)-solvation strength and facilitate the formation of Li F-rich solid-electrolyte interphase of Li metal compared to HNTs-.The resultant Li|NCCPE|LiFePO4cell delivers a capacity of 144.9 m Ah g^(-1)after 400 cycles at 0.5 C and a capacity retention of 78.6%.This study provides deep insights into understanding the roles of surface charges of nanofillers in regulating the mechanical and electrochemical interfaces in ASSLMBs.展开更多
Aqueous zinc-ion batteries are regarded as promising electrochemical energy-storage systems for various applications because of their high safety,low costs,and high capacities.However,dendrite formation and side react...Aqueous zinc-ion batteries are regarded as promising electrochemical energy-storage systems for various applications because of their high safety,low costs,and high capacities.However,dendrite formation and side reactions during zinc plating or stripping greatly reduce the capacity and cycle life of a battery and subsequently limit its practical application.To address these issues,we modified the surface of a zinc anode with a functional bilayer composed of zincophilic Cu and flexible polymer layers.The zincophilic Cu interfacial layer was prepared through CuSO_(4)solution pretreatment to serve as a nucleation site to facilitate uniform Zn deposition.Meanwhile,the polymer layer was coated onto the Cu interface layer to serve as a protective layer that would prevent side reactions between zinc and electrolytes.Benefiting from the synergistic effect of the zincophilic Cu and protective polymer layers,the symmetric battery exhibits an impressive cycle life,lasting over 2900 h at a current density of 1 m A·cm^(-2)with a capacity of 1 m A·h·cm^(-2).Moreover,a full battery paired with a vanadium oxide cathode achieves a remarkable capacity retention of 72%even after 500 cycles.展开更多
In-situ polymer electrolytes prepared by Li salt-initiated polymerization are promising electrolytes for solid-state Li metal batteries owing to their enhanced interface contact and facile and green preparation proces...In-situ polymer electrolytes prepared by Li salt-initiated polymerization are promising electrolytes for solid-state Li metal batteries owing to their enhanced interface contact and facile and green preparation process.However,conventional in-situ polymer electrolytes suffer from poor interface stability,low mechanical strength,low oxidation stability,and certain flammability.Herein,a silsesquioxane(POSS)-nanocage-crosslinked in-situ polymer electrolyte(POSS-DOL@PI-F)regulated by fluorinated plasticizer and enhanced by polyimide skeleton is fabricated by Li salt initiated in-situ polymerization.Polyimide skeleton and POSS-nanocage-crosslinked network significantly enhance the tensile strength(22.8 MPa)and thermal stability(200℃)of POSS-DOL@PI-F.Fluorinated plasticizer improves ionic conductivity(6.83×10^(-4)S cm^(-1)),flame retardance,and oxidation stability(5.0 V)of POSS-DOL@PI-F.The fluorinated plasticizer of POSS-DOL@PI-F constructs robust LiF-rich solid electrolyte interphases and cathode electrolyte interphases,thereby dramatically enhancing the interface stability of Li metal anodes and LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NCM811)cathodes.POSS-DOL@PI-F enables stable,long-term(1200 h),and dendrite-free cycle of Li‖Li cells.POSS-DOL@PI-F significantly boosts the performance of Li‖NCM811cells,which display superior cycle stability under harsh conditions of high voltage(4.5 V),high temperature(60℃),low temperature(-20℃),and high areal capacity.This work provides a rational design strategy for safe and efficient polymer electrolytes.展开更多
Electron transfer processes at polymer electrolyte/electrode interfaces play a central role in modern electrochemical devices of energy conversion,however,current understanding of electron transfers through electroche...Electron transfer processes at polymer electrolyte/electrode interfaces play a central role in modern electrochemical devices of energy conversion,however,current understanding of electron transfers through electrochemical interfaces was established exclusively based on the studies of liquid/solid electrochemical interfaces.Thus,similarities and differences of liquid and polymer electrolyte/electrode interfaces need to be mapped out to guide the design of device level electrochemical interfaces.In this work,we employ the sulfonate adsorption/desorption as a probe reaction to understand the electron-transfer steps in polymer and liquid electrolytes.Through cyclic voltametric investigations on the well-define single-crystal Pd_(ML)Pt(111)electrode,we demonstrate that the oxidative adsorption and reductive desorption of sulfonates at the polymer electrolyte/electrode interface are chemically distinct from those in liquid electrolytes,with the former occurring mostly via the proton-coupled pathway while the latter proceeding mainly through the solvation-mediated pathway.Importantly,the sulfonate adsorption/desorption behaviors of alkylsulfonates become increasingly similar to those in Nafion with longer alkyl chains,suggesting that the interfacial hydrophobicity and solvation environment conferred by the perfluorinated polymer play a decisive role in the electron-transfer mechanism.Results reported in this study highlight the mechanistic distinctions between electron-transfer processes at electrochemical interfaces involving polymer and liquid electrolytes,and provide a framework for understanding electron-transfer processes at polymer electrolyte/electrode interfaces.展开更多
Liquid phosphoric acid(PA),as the proton carrier for high temperature polymer electrolyte membrane fuel cells(HT-PEMFCs),presents challenges such as catalyst poisoning,high gas transport resistance and electrolyte los...Liquid phosphoric acid(PA),as the proton carrier for high temperature polymer electrolyte membrane fuel cells(HT-PEMFCs),presents challenges such as catalyst poisoning,high gas transport resistance and electrolyte loss.These issues significantly impede the performance and durability of HT-PEMFCs,thereby limiting their potential for further application.In this study,poly(2,3,5,6-tetrafluorostylene-4-phosphonic acid)(PWN)with intrinsic proton conduction ability was employed as catalyst layer binder to reveal the impacts of the ionomer's molecular structure on mass transport within the catalyst layer.Our findings demonstrated that increasing the phosphorylation degree of PWN could enhance both pore formation at the catalyst layer and electrode acidophilic capability while improving proton conduction ability and reducing cells'internal resistance.However,adverse effects included increased local oxygen transport resistance and decreased catalyst utilization resulting from electrode acidophilic capability.This research offers valuable insights for the relationships between micro-scale molecule structure,mesoscale electrode architecture,and membrane electrode assembly design in HT-PEMFCs.展开更多
Polymer science continues to play a transformative role in materials innovation,enabling breakthroughs across diverse domains including energy storage,flexible electronics,surface engineering,and soft robotics.At the ...Polymer science continues to play a transformative role in materials innovation,enabling breakthroughs across diverse domains including energy storage,flexible electronics,surface engineering,and soft robotics.At the heart of these advances lies a critical,often defining factor:the interface.Whether between polymers and solid substrates,liquids,gases,or other polymers,interfacial phenomena govern adhesion,wetting,energy dissipation,chemical reactivity,and signal transmission.Interfaces are not passive boundaries but active zones of complexity and function,where molecular interactions shape material performance at every scale—from nanometers to entire devices.展开更多
Solid polymer electrolytes(SPEs)are considered one of the most promising materials for all-solid-state lithium metal batteries(ASSLMBs)due to their facile processability.However,developing SPEs with both high ionic co...Solid polymer electrolytes(SPEs)are considered one of the most promising materials for all-solid-state lithium metal batteries(ASSLMBs)due to their facile processability.However,developing SPEs with both high ionic conductivity and interfacial stability remains a challenge.Here,a donor-acceptor(D-A)like solid plasticizer,tris(pentafluorophenyl)borane(TPFPB),containing electron-rich F atoms and electrondeficient B sites,was introduced to regulate the ion transport behavior and interfacial chemistry of polyethylene oxide(PEO)-based SPEs.Owing to the multiple ion-dipole interactions(F Li^(+)TFSI^(-)and B TFSI^(-)Li^(+))between the TPFPB molecule and Li salts,a multimodal electrolyte environment featuring more free Li^(+)and trapped TFSI^(-)anions was generated,which cooperates with the reduced crystallinity of PEO,significantly facilitating the rapid migration of Li^(+).More importantly,TPFPB tends to be preferentially reduced to form a stable inorganic-rich solid electrolyte interphase on the Li-metal anode,ensuring uniform Li plating/stripping behavior.Thus,the TPFPB-modulated SPEs system achieves a high Li^(+)conductivity of 0.74 m S cm^(-1)and effectively suppresses dendrite growth,which enables a long-cycle dendrite-free Li/Li symmetric cell for over 5000 h,and remarkable electrochemical performance has been further validated in operational ASSLMBs.The findings in this work would inspire efforts to develop highperformance SPEs for all-solid-state alkali-metal batteries.展开更多
Among various architectures of polymers,end-group-free rings have attracted growing interests due to their distinct physicochemical performances over the linear counterparts which are exemplified by reduced hydrodynam...Among various architectures of polymers,end-group-free rings have attracted growing interests due to their distinct physicochemical performances over the linear counterparts which are exemplified by reduced hydrodynamic size and slower degradation.It is key to develop facile methods to large-scale synthesis of polymer rings with tunable compositions and microstructures.Recent progresses in large-scale synthesis of polymer rings against single-chain dynamic nanoparticles,and the example applications in synchronous enhancing toughness and strength of polymer nanocomposites are summarized.Once there is the breakthrough in rational design and effective large-scale synthesis of polymer rings and their functional derivatives,a family of cyclic functional hybrids would be available,thus providing a new paradigm in developing polymer science and engineering.展开更多
Thermoelectric(TE)materials,being capable of converting waste heat into electricity,are pivotal for sustainable energy solutions.Among emerging TE materials,organic TE materials,particularly conjugated polymers,are ga...Thermoelectric(TE)materials,being capable of converting waste heat into electricity,are pivotal for sustainable energy solutions.Among emerging TE materials,organic TE materials,particularly conjugated polymers,are gaining prominence due to their unique combination of mechanical flexibility,environmental compatibility,and solution-processable fabrication.A notable candidate in this field is poly(2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene)(PBTTT),a liquid-crystalline conjugated polymer,with high charge carrier mobility and adaptability to melt-processing techniques.Recent advancements have propelled PBTTT’s figure of merit from below 0.1 to a remarkable 1.28 at 368 K,showcasing its potential for practical applications.This review systematically examines strategies to enhance PBTTT’s TE performance through doping(solution,vapor,and anion exchange doping),composite engineering,and aggregation state controlling.Recent key breakthroughs include ion exchange doping for stable charge modulation,multi-heterojunction architectures reducing thermal conductivity,and proton-coupled electron transfer doping for precise Fermi-level tuning.Despite great progress,challenges still persist in enhancing TE conversion efficiency,balancing or decoupling electrical conductivity,Seebeck coefficient and thermal conductivity,and leveraging melt-processing scalability of PBTTT.By bridging fundamental insights with applied research,this work provides a roadmap for advancing PBTTT-based TE materials toward efficient energy harvesting and wearable electronics.展开更多
To investigate the pore structure of graphene oxide modified polymer cement mortar(GOPM)under salt-freeze-thaw(SFT)coupling effects and its impact on deterioration,this study modifies polymer cement mortar(EMCM)with g...To investigate the pore structure of graphene oxide modified polymer cement mortar(GOPM)under salt-freeze-thaw(SFT)coupling effects and its impact on deterioration,this study modifies polymer cement mortar(EMCM)with graphene oxide(GO).The micro-pore structure of GOPM is characterized using LF-NMR and SEM.Fractal theory is applied to calculate the fractal dimension of pore volume,and the deterioration patterns are analyzed based on the evolution characteristics of capillary pores.The experimental results indicate that,after 25 salt-freeze-thaw cycles(SFTc),SO2-4 ions penetrate the matrix,generating corrosion products that fill existing pores and enhance the compactness of the specimen.As the number of cycles increases,the ongoing formation and expansion of corrosion products within the matrix,combined with persistent freezing forces,and result in the degradation of the pore structure.Therefore,the mass loss rate(MLR)of the specimens shows a trend of first decreasing and then increasing,while the relative dynamic elastic modulus(RDEM)initially increases and then decreases.Compared to the PC group specimens,the G3PM group specimens show a 28.71% reduction in MLR and a 31.42% increase in RDEM after 150 SFTc.The fractal dimensions of the transition pores,capillary pores,and macropores in the G3PM specimens first increase and then decrease as the number of SFTc increases.Among them,the capillary pores show the highest correlation with MLR and RDEM,with correlation coefficients of 0.97438 and 0.98555,respectively.展开更多
Bone regeneration for non-load-bearing defects remains a significant clinical challenge requiring advanced biomaterials and cellular strategies.Adiposederived mesenchymal stem cells(AD-MSCs)have garnered significant i...Bone regeneration for non-load-bearing defects remains a significant clinical challenge requiring advanced biomaterials and cellular strategies.Adiposederived mesenchymal stem cells(AD-MSCs)have garnered significant interest in bone tissue engineering(BTE)because of their abundant availability,minimally invasive harvesting procedures,and robust differentiation potential into osteogenic lineages.Unlike bone marrow-derived mesenchymal stem cells,AD-MSCs can be easily obtained in large quantities,making them appealing alternatives for therapeutic applications.This review explores hydrogels containing polymers,such as chitosan,collagen,gelatin,and hyaluronic acid,and their composites,tailored for BTE,and emphasizes the importance of these hydrogels as scaffolds for the delivery of AD-MSCs.Various hydrogel fabrication techniques and biocompatibility assessments are discussed,along with innovative modifications to enhance osteogenesis.This review also briefly outlines AD-MSC isolation methods and advanced embedding techniques for precise cell placement,such as direct encapsulation and three-dimensional bioprinting.We discuss the mechanisms of bone regeneration in the AD-MSC-laden hydrogels,including osteoinduction,vascularization,and extracellular matrix remodeling.We also review the preclinical and clinical applications of AD-MSC-hydrogel systems,emphasizing their success and limitations.In this review,we provide a comprehensive overview of AD-MSC-based hydrogel systems to guide the development of effective therapies for bone regeneration.展开更多
High-performance lithium metal batteries benefit from the construction of composite polymer electrolytes(CPEs)which are synthesized by incorporating inorganic fillers into polymer matrices[1].However,the random distri...High-performance lithium metal batteries benefit from the construction of composite polymer electrolytes(CPEs)which are synthesized by incorporating inorganic fillers into polymer matrices[1].However,the random distribution of added fillers within the polymer matrix can lead to tortuous ion pathways and longer transmission distances(Fig.1).As a result,the ion transport capability of CPEs may decrease,while interface contact may deteriorate.Therefore,the organized arrangement of fillers emerges as a crucial consideration in constructing electrolyte membranes.One highly effective approach is the adoption of a vertically aligned filler configuration,where ceramic fillers are constructed to be perpendicular to the electrolyte membrane.If so,the filler/electrolyte interface impedance can be significantly reduced,while continuous ion transport channels along the specified direction are formed,thus significantly enhancing the ion conduction(Fig.1(a))[1].展开更多
Amyloid-like proteins are critical for interfacial adhesion across various marine organisms and bacteria.However,the specific contributions of different functional residues remain unclear.Herein,we introduce an approa...Amyloid-like proteins are critical for interfacial adhesion across various marine organisms and bacteria.However,the specific contributions of different functional residues remain unclear.Herein,we introduce an approach to deconstruct and mimic these residues using synthetic homopolymers and random copolymers with phenyl,amino,carboxyl,and hydroxyl functional groups using reversible addition-fragmentation chain transfer(RAFT)polymerization.The resulting polymers,designed with comparable molecular weights(M_(n):10–20 kDa)and narrow dispersities(PDI<1.3),mimic the diverse surface chemistry of amyloid-like proteins,enabling systematic investigation of their adhesive properties.The interfacial adhesion forces of different polymer films were quantified using atomic force microscopy(AFM)with a colloidal probe.Remarkably copolymers with multiple functional groups demonstrated significantly enhanced adhesion compared to homopolymers,a trend corroborated by macroscopic shear strength and stability tests.These results highlight that the synergistic effects of multiple functional groups are crucial for achieving universal interfacial adhesion of macromolecules,offering insights into protein adhesion mechanisms,and guiding polymer-based interfacial modifications.展开更多
The solvent-free in situ polymerization technique has the potential to tailor-make conformal interfaces that are essential for developing durable and safe lithium metal polymer batteries(LMPBs).Hence,much attention ha...The solvent-free in situ polymerization technique has the potential to tailor-make conformal interfaces that are essential for developing durable and safe lithium metal polymer batteries(LMPBs).Hence,much attention has been given to the eco-friendly and rapid ultraviolet(UV)-induced in situ photopolymerization process to prepare solid-state polymer electrolytes.In this respect,an innovative method is proposed here to overcome the challenges of UV-induced photopolymerization(UV-curing)in the zones where UV-light cannot penetrate,especially in LMPBs where thick electrodes are used.The proposed frontal-inspired photopolymerization(FIPP)process is a diverged frontal-based technique that uses two classes(dual)of initiators to improve the slow reaction kinetics of allyl-based monomers/oligomers by at least 50%compared with the conventional UV-curing process.The possible reaction mechanism occurring in FIPP is demonstrated using density functional theory calculations and spectroscopic investigations.Indeed,the initiation mechanism identified for the FIPP relies on a photochemical pathway rather than an exothermic propagating front forms during the UV-irradiation step as the case with the classical frontal photopolymerization technique.Besides,the FIPP-based in situ cell fabrication using dual initiators is advantageous over both the sandwich cell assembly and conventional in situ photopolymerization in overcoming the limitations of mass transport and active material utilization in high energy and high power LMPBs that use thick electrodes.Furthermore,the LMPB cells fabricated using the in situ-FIPP process with high mass loading LiFePO_(4)electrodes(5.2 mg cm^(-2))demonstrate higher rate capability,and a 50%increase in specific capacity against a sandwich cell encouraging the use of this innovative process in large-scale solid-state battery production.展开更多
Organic electrochemical transistors(OECTs)have emerged as versatile platforms for broad applications spanning from flexible and wearable integrated circuits to biomedical monitoring to neuromorphic computing.A variety...Organic electrochemical transistors(OECTs)have emerged as versatile platforms for broad applications spanning from flexible and wearable integrated circuits to biomedical monitoring to neuromorphic computing.A variety of materials and tailored micro/nanostructures have recently been developed to realized stretchable OECTs,however,a solid-state OECT with high elasticity has not been demonstrated to date.Herein,we present a general platform developed for the facile generation of highly elastic all-polymer OECTs with high transconductance(up to 12.7 mS),long-term mechanical and environmental durability,and sustainability.Rapid prototyping of these devices was achieved simply by transfer printing lithium bis(trifluoromethane)sulfonimide doped poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS/LiTFSI)microstructures onto a resilient gelatin-based gel electrolyte,in which both depletion-mode and enhancement-mode OECTs were produced using various active channels.Remarkably,the elaborate 3D architectures of the PEDOT:PSS were engineered,and an imprinted 3D-microstructured channel/electrolyte interface combined with wrinkled electrodes provided performance that was retained(>70%)through biaxial stretching of 100%strain and after 1000 repeated cycles of 80%strain.Furthermore,the anti-drying and degradable gelatin and the self-crosslinked PEDOT:PSS/LiTFSI jointly enabled stability during>4 months of storage and on-demand disposal and recycling.This work thus represents a straightforward approach towards high-performance stretchable organic electronics for wearable/implantable/neuromorphic/sustainable applications.展开更多
Accurately estimating the interfacial bond capacity of the near-surface mounted(NSM)carbon fiber-reinforced polymer(CFRP)to concrete joint is a fundamental task in the strengthening and retrofit of existing reinforced...Accurately estimating the interfacial bond capacity of the near-surface mounted(NSM)carbon fiber-reinforced polymer(CFRP)to concrete joint is a fundamental task in the strengthening and retrofit of existing reinforced concrete(RC)structures.The machine learning(ML)approach may provide an alternative to the commonly used semi-empirical or semi-analytical methods.Therefore,in this work we have developed a predictive model based on an artificial neural network(ANN)approach,i.e.using a back propagation neural network(BPNN),to map the complex data pattern obtained from an NSM CFRP to concrete joint.It involves a set of nine material and geometric input parameters and one output value.Moreover,by employing the neural interpretation diagram(NID)technique,the BPNN model becomes interpretable,as the influence of each input variable on the model can be tracked and quantified based on the connection weights of the neural network.An extensive database including 163 pull-out testing samples,collected from the authors’research group and from published results in the literature,is used to train and verify the ANN.Our results show that the prediction given by the BPNN model agrees well with the experimental data and yields a coefficient of determination of 0.957 on the whole database.After removing one non-significant feature,the BPNN becomes even more computationally efficient and accurate.In addition,compared with the existed semi-analytical model,the ANN-based approach demonstrates a more accurate estimation.Therefore,the proposed ML method may be a promising alternative for predicting the bond strength of NSM CFRP to concrete joint for structural engineers.展开更多
As an important component,the bond behavior of carbon fiber-reinforced polymer(CFRP)-concrete interface for a reinforced concrete(RC)beam is very significant.In this study,a theoretical model was established to analyz...As an important component,the bond behavior of carbon fiber-reinforced polymer(CFRP)-concrete interface for a reinforced concrete(RC)beam is very significant.In this study,a theoretical model was established to analyze the flexural behavior of CFRP-strengthened RC beams,and the CFRP-concrete interfacial bond-slip relationship under hygrothermal environment was unified into one model.Two failure criteria corresponding to two types of failure modes,i.e.,concrete crushing and intermediate crack(IC)-induced debonding,were developed.Through the theoretical model,the flexural behavior of deflection,interfacial shear stress distribution and ultimate load of a CFRP-strengthened RC beam under hygrothermal environment were obtained and predicted.Moreover,the theoretical model was verified by test results.The results showed that the hygrothermal environment had a significant impact on the CFRP-concrete interface behavior.Compared with the control beam without hygrothermal environment pretreatment,the deflection and ultimate load of the strengthened RC beam decreased by 51.9%and 20%,respectively.展开更多
The effective conductivity of graphene-based nanocomposites is suggested by the characteristics of polymer-filler interfacial areas as well as the contact resistance between the neighboring nanosheets.The interfacial ...The effective conductivity of graphene-based nanocomposites is suggested by the characteristics of polymer-filler interfacial areas as well as the contact resistance between the neighboring nanosheets.The interfacial properties are expressed by the effective levels of the inverse aspect ratio and the filler volume fraction.Moreover,the resistances of components in the contact regions are used to define the contact resistance,which inversely affects the effective conductivity.The obtained model is utilized to predict the effective conductivity for some examples.The discrepancy of the effective conductivity at various ranks of all factors is clarified.The interfacial conductivity directly controls the effective conductivity,while the filler conductivity plays a dissimilar role in the effective conductivity,due to the incomplete interfacial adhesion.A high operative conductivity is also achieved by small contact distances and high interfacial properties.Additionally,big contact diameters and little tunnel resistivity decrease the contact resistance,thus enhancing the effective conductivity.展开更多
文摘Blend based polymer nanocomposites, comprising Janus nanoparticles at their polymer/polymer interface, were analytically/experimentally evaluated. The modeling procedure was performed in two stages: first, modeling of polymer/polymer interface region comprising Janus nanoparticles and second, modeling of the entire systems as a function of the variation of the blend morphology.In the first stage, the modeling procedure was performed based on the development of the model proposed by Ji et al. and in the second stage, the fundamental of Kolarik's model was used in order to propose a developed and more practical model. It was shown that Janus nanoparticles may form dual polymer/particle interphase at polymer/polymer interface which can drastically affect the final mechanical properties of the system. Comparing the results of tensile tests imposed on different prepared samples with the predictions of the model proved its accuracy and reliability(error < 9%).
文摘In this work,a unique model is proposed for predicting the tensile strength of binary polymer blends considering the effects of polymer/polymer interface and the morphological variation of the system.The modeling was performed based on the combination of analytical and artificial neural network (ANN) modeling methods.For the analytical part,Kolarik’s model was developed in accordance with the system requirements and ANN was simultaneously involved in order to interpret some effective model parameters using the tensile test result of an actual sample (e.g.the yield strength and thickness of the interface,etc.).Furthermore,the model accuracy was evaluated by comparing the tensile test results of differently preparediPP/PA and PS/PMMA blend samples and also some other data from literature with the model predictions.It was revealed that the designed ANN perfectly elevates the capability of the analytical section in order to predict the tensile strength of binary polymer blends with different compositions (prediction error <10%).
基金the financial support from the National Natural Science Foundation of China(52203123 and 52473248)State Key Laboratory of Polymer Materials Engineering(sklpme2024-2-04)+1 种基金the Fundamental Research Funds for the Central Universitiessponsored by the Double First-Class Construction Funds of Sichuan University。
文摘Composite polymer electrolytes(CPEs)offer a promising solution for all-solid-state lithium-metal batteries(ASSLMBs).However,conventional nanofillers with Lewis-acid-base surfaces make limited contribution to improving the overall performance of CPEs due to their difficulty in achieving robust electrochemical and mechanical interfaces simultaneously.Here,by regulating the surface charge characteristics of halloysite nanotube(HNT),we propose a concept of lithium-ion dynamic interface(Li^(+)-DI)engineering in nano-charged CPE(NCCPE).Results show that the surface charge characteristics of HNTs fundamentally change the Li^(+)-DI,and thereof the mechanical and ion-conduction behaviors of the NCCPEs.Particularly,the HNTs with positively charged surface(HNTs+)lead to a higher Li^(+)transference number(0.86)than that of HNTs-(0.73),but a lower toughness(102.13 MJ m^(-3)for HNTs+and 159.69 MJ m^(-3)for HNTs-).Meanwhile,a strong interface compatibilization effect by Li^(+)is observed for especially the HNTs+-involved Li^(+)-DI,which improves the toughness by 2000%compared with the control.Moreover,HNTs+are more effective to weaken the Li^(+)-solvation strength and facilitate the formation of Li F-rich solid-electrolyte interphase of Li metal compared to HNTs-.The resultant Li|NCCPE|LiFePO4cell delivers a capacity of 144.9 m Ah g^(-1)after 400 cycles at 0.5 C and a capacity retention of 78.6%.This study provides deep insights into understanding the roles of surface charges of nanofillers in regulating the mechanical and electrochemical interfaces in ASSLMBs.
基金financially supported by the Science and Technology Development Project of Henan Province,China(No.242102241042)the Joint Fund of Henan Province Science and Technology R&D Program(No.225200810093)+1 种基金the Startup Research of Henan Academy of Sciences(No.231817001)the Key Innovation Projects for Postgraduates of Henan Academy of Sciences(No.24331712)。
文摘Aqueous zinc-ion batteries are regarded as promising electrochemical energy-storage systems for various applications because of their high safety,low costs,and high capacities.However,dendrite formation and side reactions during zinc plating or stripping greatly reduce the capacity and cycle life of a battery and subsequently limit its practical application.To address these issues,we modified the surface of a zinc anode with a functional bilayer composed of zincophilic Cu and flexible polymer layers.The zincophilic Cu interfacial layer was prepared through CuSO_(4)solution pretreatment to serve as a nucleation site to facilitate uniform Zn deposition.Meanwhile,the polymer layer was coated onto the Cu interface layer to serve as a protective layer that would prevent side reactions between zinc and electrolytes.Benefiting from the synergistic effect of the zincophilic Cu and protective polymer layers,the symmetric battery exhibits an impressive cycle life,lasting over 2900 h at a current density of 1 m A·cm^(-2)with a capacity of 1 m A·h·cm^(-2).Moreover,a full battery paired with a vanadium oxide cathode achieves a remarkable capacity retention of 72%even after 500 cycles.
基金supported by the National Natural Science Foundation of China(22375116,22001057)the Science Foundation of High-Level Talents of Wuyi University(2019AL017,2021AL002)Tianjin Lishen Battery Co.,Ltd。
文摘In-situ polymer electrolytes prepared by Li salt-initiated polymerization are promising electrolytes for solid-state Li metal batteries owing to their enhanced interface contact and facile and green preparation process.However,conventional in-situ polymer electrolytes suffer from poor interface stability,low mechanical strength,low oxidation stability,and certain flammability.Herein,a silsesquioxane(POSS)-nanocage-crosslinked in-situ polymer electrolyte(POSS-DOL@PI-F)regulated by fluorinated plasticizer and enhanced by polyimide skeleton is fabricated by Li salt initiated in-situ polymerization.Polyimide skeleton and POSS-nanocage-crosslinked network significantly enhance the tensile strength(22.8 MPa)and thermal stability(200℃)of POSS-DOL@PI-F.Fluorinated plasticizer improves ionic conductivity(6.83×10^(-4)S cm^(-1)),flame retardance,and oxidation stability(5.0 V)of POSS-DOL@PI-F.The fluorinated plasticizer of POSS-DOL@PI-F constructs robust LiF-rich solid electrolyte interphases and cathode electrolyte interphases,thereby dramatically enhancing the interface stability of Li metal anodes and LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NCM811)cathodes.POSS-DOL@PI-F enables stable,long-term(1200 h),and dendrite-free cycle of Li‖Li cells.POSS-DOL@PI-F significantly boosts the performance of Li‖NCM811cells,which display superior cycle stability under harsh conditions of high voltage(4.5 V),high temperature(60℃),low temperature(-20℃),and high areal capacity.This work provides a rational design strategy for safe and efficient polymer electrolytes.
基金supported by the National Key R&D Program of China(No.2021YFA1501003)。
文摘Electron transfer processes at polymer electrolyte/electrode interfaces play a central role in modern electrochemical devices of energy conversion,however,current understanding of electron transfers through electrochemical interfaces was established exclusively based on the studies of liquid/solid electrochemical interfaces.Thus,similarities and differences of liquid and polymer electrolyte/electrode interfaces need to be mapped out to guide the design of device level electrochemical interfaces.In this work,we employ the sulfonate adsorption/desorption as a probe reaction to understand the electron-transfer steps in polymer and liquid electrolytes.Through cyclic voltametric investigations on the well-define single-crystal Pd_(ML)Pt(111)electrode,we demonstrate that the oxidative adsorption and reductive desorption of sulfonates at the polymer electrolyte/electrode interface are chemically distinct from those in liquid electrolytes,with the former occurring mostly via the proton-coupled pathway while the latter proceeding mainly through the solvation-mediated pathway.Importantly,the sulfonate adsorption/desorption behaviors of alkylsulfonates become increasingly similar to those in Nafion with longer alkyl chains,suggesting that the interfacial hydrophobicity and solvation environment conferred by the perfluorinated polymer play a decisive role in the electron-transfer mechanism.Results reported in this study highlight the mechanistic distinctions between electron-transfer processes at electrochemical interfaces involving polymer and liquid electrolytes,and provide a framework for understanding electron-transfer processes at polymer electrolyte/electrode interfaces.
基金supported by The National Key Research and Development Program of China(2021YFB4001204)National Natural Science Foundation of China(22179130,22379143,22479145)。
文摘Liquid phosphoric acid(PA),as the proton carrier for high temperature polymer electrolyte membrane fuel cells(HT-PEMFCs),presents challenges such as catalyst poisoning,high gas transport resistance and electrolyte loss.These issues significantly impede the performance and durability of HT-PEMFCs,thereby limiting their potential for further application.In this study,poly(2,3,5,6-tetrafluorostylene-4-phosphonic acid)(PWN)with intrinsic proton conduction ability was employed as catalyst layer binder to reveal the impacts of the ionomer's molecular structure on mass transport within the catalyst layer.Our findings demonstrated that increasing the phosphorylation degree of PWN could enhance both pore formation at the catalyst layer and electrode acidophilic capability while improving proton conduction ability and reducing cells'internal resistance.However,adverse effects included increased local oxygen transport resistance and decreased catalyst utilization resulting from electrode acidophilic capability.This research offers valuable insights for the relationships between micro-scale molecule structure,mesoscale electrode architecture,and membrane electrode assembly design in HT-PEMFCs.
文摘Polymer science continues to play a transformative role in materials innovation,enabling breakthroughs across diverse domains including energy storage,flexible electronics,surface engineering,and soft robotics.At the heart of these advances lies a critical,often defining factor:the interface.Whether between polymers and solid substrates,liquids,gases,or other polymers,interfacial phenomena govern adhesion,wetting,energy dissipation,chemical reactivity,and signal transmission.Interfaces are not passive boundaries but active zones of complexity and function,where molecular interactions shape material performance at every scale—from nanometers to entire devices.
基金supported by the National Natural Science Foundation of China(No.52203261,No.52473213)。
文摘Solid polymer electrolytes(SPEs)are considered one of the most promising materials for all-solid-state lithium metal batteries(ASSLMBs)due to their facile processability.However,developing SPEs with both high ionic conductivity and interfacial stability remains a challenge.Here,a donor-acceptor(D-A)like solid plasticizer,tris(pentafluorophenyl)borane(TPFPB),containing electron-rich F atoms and electrondeficient B sites,was introduced to regulate the ion transport behavior and interfacial chemistry of polyethylene oxide(PEO)-based SPEs.Owing to the multiple ion-dipole interactions(F Li^(+)TFSI^(-)and B TFSI^(-)Li^(+))between the TPFPB molecule and Li salts,a multimodal electrolyte environment featuring more free Li^(+)and trapped TFSI^(-)anions was generated,which cooperates with the reduced crystallinity of PEO,significantly facilitating the rapid migration of Li^(+).More importantly,TPFPB tends to be preferentially reduced to form a stable inorganic-rich solid electrolyte interphase on the Li-metal anode,ensuring uniform Li plating/stripping behavior.Thus,the TPFPB-modulated SPEs system achieves a high Li^(+)conductivity of 0.74 m S cm^(-1)and effectively suppresses dendrite growth,which enables a long-cycle dendrite-free Li/Li symmetric cell for over 5000 h,and remarkable electrochemical performance has been further validated in operational ASSLMBs.The findings in this work would inspire efforts to develop highperformance SPEs for all-solid-state alkali-metal batteries.
基金Supported by the National Natural Science Foundation of China(Nos.52293472,22473096 and 22471164)。
文摘Among various architectures of polymers,end-group-free rings have attracted growing interests due to their distinct physicochemical performances over the linear counterparts which are exemplified by reduced hydrodynamic size and slower degradation.It is key to develop facile methods to large-scale synthesis of polymer rings with tunable compositions and microstructures.Recent progresses in large-scale synthesis of polymer rings against single-chain dynamic nanoparticles,and the example applications in synchronous enhancing toughness and strength of polymer nanocomposites are summarized.Once there is the breakthrough in rational design and effective large-scale synthesis of polymer rings and their functional derivatives,a family of cyclic functional hybrids would be available,thus providing a new paradigm in developing polymer science and engineering.
基金financial support by Guangdong Basic and Applied Basic Research Foundation(2025A1515012415)National Natural Science Foundation of China(52242305)the Stable Support Project of Shenzhen(Project No.20231122125728001).
文摘Thermoelectric(TE)materials,being capable of converting waste heat into electricity,are pivotal for sustainable energy solutions.Among emerging TE materials,organic TE materials,particularly conjugated polymers,are gaining prominence due to their unique combination of mechanical flexibility,environmental compatibility,and solution-processable fabrication.A notable candidate in this field is poly(2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene)(PBTTT),a liquid-crystalline conjugated polymer,with high charge carrier mobility and adaptability to melt-processing techniques.Recent advancements have propelled PBTTT’s figure of merit from below 0.1 to a remarkable 1.28 at 368 K,showcasing its potential for practical applications.This review systematically examines strategies to enhance PBTTT’s TE performance through doping(solution,vapor,and anion exchange doping),composite engineering,and aggregation state controlling.Recent key breakthroughs include ion exchange doping for stable charge modulation,multi-heterojunction architectures reducing thermal conductivity,and proton-coupled electron transfer doping for precise Fermi-level tuning.Despite great progress,challenges still persist in enhancing TE conversion efficiency,balancing or decoupling electrical conductivity,Seebeck coefficient and thermal conductivity,and leveraging melt-processing scalability of PBTTT.By bridging fundamental insights with applied research,this work provides a roadmap for advancing PBTTT-based TE materials toward efficient energy harvesting and wearable electronics.
基金Funded by the National Natural Science Foundation of China(Nos.5226804252468035)。
文摘To investigate the pore structure of graphene oxide modified polymer cement mortar(GOPM)under salt-freeze-thaw(SFT)coupling effects and its impact on deterioration,this study modifies polymer cement mortar(EMCM)with graphene oxide(GO).The micro-pore structure of GOPM is characterized using LF-NMR and SEM.Fractal theory is applied to calculate the fractal dimension of pore volume,and the deterioration patterns are analyzed based on the evolution characteristics of capillary pores.The experimental results indicate that,after 25 salt-freeze-thaw cycles(SFTc),SO2-4 ions penetrate the matrix,generating corrosion products that fill existing pores and enhance the compactness of the specimen.As the number of cycles increases,the ongoing formation and expansion of corrosion products within the matrix,combined with persistent freezing forces,and result in the degradation of the pore structure.Therefore,the mass loss rate(MLR)of the specimens shows a trend of first decreasing and then increasing,while the relative dynamic elastic modulus(RDEM)initially increases and then decreases.Compared to the PC group specimens,the G3PM group specimens show a 28.71% reduction in MLR and a 31.42% increase in RDEM after 150 SFTc.The fractal dimensions of the transition pores,capillary pores,and macropores in the G3PM specimens first increase and then decrease as the number of SFTc increases.Among them,the capillary pores show the highest correlation with MLR and RDEM,with correlation coefficients of 0.97438 and 0.98555,respectively.
文摘Bone regeneration for non-load-bearing defects remains a significant clinical challenge requiring advanced biomaterials and cellular strategies.Adiposederived mesenchymal stem cells(AD-MSCs)have garnered significant interest in bone tissue engineering(BTE)because of their abundant availability,minimally invasive harvesting procedures,and robust differentiation potential into osteogenic lineages.Unlike bone marrow-derived mesenchymal stem cells,AD-MSCs can be easily obtained in large quantities,making them appealing alternatives for therapeutic applications.This review explores hydrogels containing polymers,such as chitosan,collagen,gelatin,and hyaluronic acid,and their composites,tailored for BTE,and emphasizes the importance of these hydrogels as scaffolds for the delivery of AD-MSCs.Various hydrogel fabrication techniques and biocompatibility assessments are discussed,along with innovative modifications to enhance osteogenesis.This review also briefly outlines AD-MSC isolation methods and advanced embedding techniques for precise cell placement,such as direct encapsulation and three-dimensional bioprinting.We discuss the mechanisms of bone regeneration in the AD-MSC-laden hydrogels,including osteoinduction,vascularization,and extracellular matrix remodeling.We also review the preclinical and clinical applications of AD-MSC-hydrogel systems,emphasizing their success and limitations.In this review,we provide a comprehensive overview of AD-MSC-based hydrogel systems to guide the development of effective therapies for bone regeneration.
基金supported by the National Natural Science Foundation of China(No.51972293)Hangzhou Key Research Program Project(2023SZD0099)LingYan Project(2024C01090).
文摘High-performance lithium metal batteries benefit from the construction of composite polymer electrolytes(CPEs)which are synthesized by incorporating inorganic fillers into polymer matrices[1].However,the random distribution of added fillers within the polymer matrix can lead to tortuous ion pathways and longer transmission distances(Fig.1).As a result,the ion transport capability of CPEs may decrease,while interface contact may deteriorate.Therefore,the organized arrangement of fillers emerges as a crucial consideration in constructing electrolyte membranes.One highly effective approach is the adoption of a vertically aligned filler configuration,where ceramic fillers are constructed to be perpendicular to the electrolyte membrane.If so,the filler/electrolyte interface impedance can be significantly reduced,while continuous ion transport channels along the specified direction are formed,thus significantly enhancing the ion conduction(Fig.1(a))[1].
基金supported by the National Natural Science Foundation of China(Nos.22375122 and 22105065)the National Science Fund for Distinguished Young Scholars(No.52225301)+3 种基金the National Key R&D Program of China(Nos.2020YFA0710400 and 2020YFA0710402)the 111 Project(No.B14041)Fundamental Research Funds for Central Universities(No.GK202304040)Open Project of the State Key Laboratory of Supramolecular Structure and Materials(No.sklssm2024023)。
文摘Amyloid-like proteins are critical for interfacial adhesion across various marine organisms and bacteria.However,the specific contributions of different functional residues remain unclear.Herein,we introduce an approach to deconstruct and mimic these residues using synthetic homopolymers and random copolymers with phenyl,amino,carboxyl,and hydroxyl functional groups using reversible addition-fragmentation chain transfer(RAFT)polymerization.The resulting polymers,designed with comparable molecular weights(M_(n):10–20 kDa)and narrow dispersities(PDI<1.3),mimic the diverse surface chemistry of amyloid-like proteins,enabling systematic investigation of their adhesive properties.The interfacial adhesion forces of different polymer films were quantified using atomic force microscopy(AFM)with a colloidal probe.Remarkably copolymers with multiple functional groups demonstrated significantly enhanced adhesion compared to homopolymers,a trend corroborated by macroscopic shear strength and stability tests.These results highlight that the synergistic effects of multiple functional groups are crucial for achieving universal interfacial adhesion of macromolecules,offering insights into protein adhesion mechanisms,and guiding polymer-based interfacial modifications.
基金The support provided by the German Federal Ministry of Education and Research(BMBF)within the project“Benchbatt”(03XP0047B)is gratefully acknowledged.
文摘The solvent-free in situ polymerization technique has the potential to tailor-make conformal interfaces that are essential for developing durable and safe lithium metal polymer batteries(LMPBs).Hence,much attention has been given to the eco-friendly and rapid ultraviolet(UV)-induced in situ photopolymerization process to prepare solid-state polymer electrolytes.In this respect,an innovative method is proposed here to overcome the challenges of UV-induced photopolymerization(UV-curing)in the zones where UV-light cannot penetrate,especially in LMPBs where thick electrodes are used.The proposed frontal-inspired photopolymerization(FIPP)process is a diverged frontal-based technique that uses two classes(dual)of initiators to improve the slow reaction kinetics of allyl-based monomers/oligomers by at least 50%compared with the conventional UV-curing process.The possible reaction mechanism occurring in FIPP is demonstrated using density functional theory calculations and spectroscopic investigations.Indeed,the initiation mechanism identified for the FIPP relies on a photochemical pathway rather than an exothermic propagating front forms during the UV-irradiation step as the case with the classical frontal photopolymerization technique.Besides,the FIPP-based in situ cell fabrication using dual initiators is advantageous over both the sandwich cell assembly and conventional in situ photopolymerization in overcoming the limitations of mass transport and active material utilization in high energy and high power LMPBs that use thick electrodes.Furthermore,the LMPB cells fabricated using the in situ-FIPP process with high mass loading LiFePO_(4)electrodes(5.2 mg cm^(-2))demonstrate higher rate capability,and a 50%increase in specific capacity against a sandwich cell encouraging the use of this innovative process in large-scale solid-state battery production.
基金supported by National Natural Science Fund of China(21802171,22075325)Guangzhou Municipal Science and Technology Project(202002030434).
文摘Organic electrochemical transistors(OECTs)have emerged as versatile platforms for broad applications spanning from flexible and wearable integrated circuits to biomedical monitoring to neuromorphic computing.A variety of materials and tailored micro/nanostructures have recently been developed to realized stretchable OECTs,however,a solid-state OECT with high elasticity has not been demonstrated to date.Herein,we present a general platform developed for the facile generation of highly elastic all-polymer OECTs with high transconductance(up to 12.7 mS),long-term mechanical and environmental durability,and sustainability.Rapid prototyping of these devices was achieved simply by transfer printing lithium bis(trifluoromethane)sulfonimide doped poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS/LiTFSI)microstructures onto a resilient gelatin-based gel electrolyte,in which both depletion-mode and enhancement-mode OECTs were produced using various active channels.Remarkably,the elaborate 3D architectures of the PEDOT:PSS were engineered,and an imprinted 3D-microstructured channel/electrolyte interface combined with wrinkled electrodes provided performance that was retained(>70%)through biaxial stretching of 100%strain and after 1000 repeated cycles of 80%strain.Furthermore,the anti-drying and degradable gelatin and the self-crosslinked PEDOT:PSS/LiTFSI jointly enabled stability during>4 months of storage and on-demand disposal and recycling.This work thus represents a straightforward approach towards high-performance stretchable organic electronics for wearable/implantable/neuromorphic/sustainable applications.
基金the National Natural Science Foundation of China(No.51808056)the Hunan Provincial Natural Science Foundation of China(No.2020JJ5583)+1 种基金the Research Foundation of Education Bureau of Hunan Province(No.19B012)the China Scholarship Council(No.201808430232)。
文摘Accurately estimating the interfacial bond capacity of the near-surface mounted(NSM)carbon fiber-reinforced polymer(CFRP)to concrete joint is a fundamental task in the strengthening and retrofit of existing reinforced concrete(RC)structures.The machine learning(ML)approach may provide an alternative to the commonly used semi-empirical or semi-analytical methods.Therefore,in this work we have developed a predictive model based on an artificial neural network(ANN)approach,i.e.using a back propagation neural network(BPNN),to map the complex data pattern obtained from an NSM CFRP to concrete joint.It involves a set of nine material and geometric input parameters and one output value.Moreover,by employing the neural interpretation diagram(NID)technique,the BPNN model becomes interpretable,as the influence of each input variable on the model can be tracked and quantified based on the connection weights of the neural network.An extensive database including 163 pull-out testing samples,collected from the authors’research group and from published results in the literature,is used to train and verify the ANN.Our results show that the prediction given by the BPNN model agrees well with the experimental data and yields a coefficient of determination of 0.957 on the whole database.After removing one non-significant feature,the BPNN becomes even more computationally efficient and accurate.In addition,compared with the existed semi-analytical model,the ANN-based approach demonstrates a more accurate estimation.Therefore,the proposed ML method may be a promising alternative for predicting the bond strength of NSM CFRP to concrete joint for structural engineers.
基金The authors would like to acknowledge the financial support from the National Natural Science Foundation of China(Nos.11872185,11627802,51678249,11132004)the Natural Science Foundation of Guangdong Province(No.2019A1515012222).
文摘As an important component,the bond behavior of carbon fiber-reinforced polymer(CFRP)-concrete interface for a reinforced concrete(RC)beam is very significant.In this study,a theoretical model was established to analyze the flexural behavior of CFRP-strengthened RC beams,and the CFRP-concrete interfacial bond-slip relationship under hygrothermal environment was unified into one model.Two failure criteria corresponding to two types of failure modes,i.e.,concrete crushing and intermediate crack(IC)-induced debonding,were developed.Through the theoretical model,the flexural behavior of deflection,interfacial shear stress distribution and ultimate load of a CFRP-strengthened RC beam under hygrothermal environment were obtained and predicted.Moreover,the theoretical model was verified by test results.The results showed that the hygrothermal environment had a significant impact on the CFRP-concrete interface behavior.Compared with the control beam without hygrothermal environment pretreatment,the deflection and ultimate load of the strengthened RC beam decreased by 51.9%and 20%,respectively.
基金Project supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education,Science and Technology(No.2022R1A2C1004437)。
文摘The effective conductivity of graphene-based nanocomposites is suggested by the characteristics of polymer-filler interfacial areas as well as the contact resistance between the neighboring nanosheets.The interfacial properties are expressed by the effective levels of the inverse aspect ratio and the filler volume fraction.Moreover,the resistances of components in the contact regions are used to define the contact resistance,which inversely affects the effective conductivity.The obtained model is utilized to predict the effective conductivity for some examples.The discrepancy of the effective conductivity at various ranks of all factors is clarified.The interfacial conductivity directly controls the effective conductivity,while the filler conductivity plays a dissimilar role in the effective conductivity,due to the incomplete interfacial adhesion.A high operative conductivity is also achieved by small contact distances and high interfacial properties.Additionally,big contact diameters and little tunnel resistivity decrease the contact resistance,thus enhancing the effective conductivity.
