Conductive hydrogels have garnered widespread attention as a versatile class of flexible electronics.Despite considerable advancements,current methodologies struggle to reconcile the fundamental trade-off between high...Conductive hydrogels have garnered widespread attention as a versatile class of flexible electronics.Despite considerable advancements,current methodologies struggle to reconcile the fundamental trade-off between high conductivity and effective absorption-dominated electromagnetic interference(EMI)shielding,as dictated by classical impedance matching theory.This study addresses these limitations by introducing a novel synthesis of aramid nanofiber/MXene-reinforced polyelectrolyte hydrogels.Leveraging the unique properties of polyelectrolytes,this innovative approach enhances ionic conductivity and exploits the hydration effect of hydrophilic polar groups to induce the formation of intermediate water.This critical innovation facilitates polarization relaxation and rearrangement in response to electromagnetic fields,thereby significantly enhancing the EMI shielding effectiveness of hydrogels.The electromagnetic wave attenuation capacity of these hydrogels was thoroughly evaluated across both X-band and terahertz band frequencies,with further investigation into the impact of varying water content states-hydrated,dried,and frozen-on their electromagnetic properties.Moreover,the hydrogels exhibited promising capabilities beyond mere EMI shielding;they also served effectively as strain sensors for monitoring human motions,indicating their potential applicability in wearable electronics.This work provides a new approach to designing multifunctional hydrogels,advancing the integration of flexible,multifunctional materials in modern electronics,with potential applications in both EMI shielding and wearable technology.展开更多
Moisture-enabled electricity generation(MEG)has emerged as a promising sustainable energy harvesting technology,comparable to photovoltaics,thermoelectrics,and triboelectrics[1].MEGs generate electricity by converting...Moisture-enabled electricity generation(MEG)has emerged as a promising sustainable energy harvesting technology,comparable to photovoltaics,thermoelectrics,and triboelectrics[1].MEGs generate electricity by converting the chemical potential of moisture into electric energy through interactions with hygroscopic materials and nanostructured interfaces.Unlike solar or thermal harvesters,MEGs operate continuously by utilizing ubiquitous atmospheric moisture,granting them unique spatial and temporal adaptability.Despite nearly a decade of progress and the exploration of diverse material systems for MEG,the overall output power remains significantly limited due to inherently low charge carrier concentrations and restricted ion diffusion fluxes[2].As a result,standalone MEG devices often deliver low and unstable output,limiting practical applications.To enhance performance and versatility,recent efforts have explored hybridization of MEG with other ambient energy sources such as triboelectric or thermoelectric effects.展开更多
Polyelectrolytes(PEs)are polymers carrying ionizable groups along the chain backbone and play an important role in life and environmental sciences,industrial applications and other fields.Due to the complicated topolo...Polyelectrolytes(PEs)are polymers carrying ionizable groups along the chain backbone and play an important role in life and environmental sciences,industrial applications and other fields.Due to the complicated topological structure and electrostatic correlations of PEs,PEs exhibit very rich phase behavior and morphologies in both bulk and confined solutions.So far,many theories,simulations and machine learning approaches have been proposed to study the behavior of polyelectrolyte solutions,especially the intrinsic structure-property relationships.In this perspective,from a personal point of view,we present several recent trends in polyelectrolyte solutions.The main themes considered here are accelerated development of sequence-defined polyelectrolyte(SDPE)via artificial intelligence technology,liquid-liquid phase separation in bulk SDPE solutions,adsorption behaviors of SDPE in the vicinity of a single dielectric surface,and surface forces between two charged surfaces mediated by SDPE solutions.展开更多
In this work,we have developed a lignin-derived polymer electrolyte(LSELi),which demonstrates exceptional ionic conductivity of 1.6×10^(-3)S cm^(−1)and a high cation transference number of 0.57 at 25°C.Time ...In this work,we have developed a lignin-derived polymer electrolyte(LSELi),which demonstrates exceptional ionic conductivity of 1.6×10^(-3)S cm^(−1)and a high cation transference number of 0.57 at 25°C.Time of flight secondary ion mass spectrometry(TOF-SIMS)analysis shows that the large-size 1-ethyl-3-methylimidazolium cations(EMIM^(+))can induce the aggregation of the anionic segments in lignosulfonate to reconstruct the three-dimensional(3D)spatial structure of polyelectrolyte,thereby forming a fluent Li^(+)transport 3D network.Dielectric loss spectroscopy further reveals that within this transport network,Li^(+)transport is decoupled from the relaxation of lignosulfonate chain segments,exhibiting characteristics of rapid Li^(+)transport.Furthermore,in-situ distribution of relaxation times analysis indicates that a stable solid electrolyte interface layer is formed at the Li plating interface with LSELi,optimizing the Li plating interface and exhibiting low charge transfer impedance and stable Li plating and stripping.Thus,a substantially prolonged cycling stability and reversibility are obtained in the Li||LSELi||Li battery at 25°C(1800 h at 0.1 mA cm^(−2),0.1 mAh cm^(−2)).At 25°C,the Li||LSELi||LiFePO_(4)cell shows 132 mAh g^(−1)of capacity with 92.7%of retention over 120 cycles at 0.1 mA cm^(−2).展开更多
Molecular dynamics simulations were performed to investigate the sliding dynamics of a small charged ring chain along rigid cyclic diblock polyelectrolyte in catenane immersed in salt solution.We found that both the m...Molecular dynamics simulations were performed to investigate the sliding dynamics of a small charged ring chain along rigid cyclic diblock polyelectrolyte in catenane immersed in salt solution.We found that both the mean-square displacement g_(3)(t)and diffusion coefficient D of ring are influenced by the salt type,electrostatic interaction strength A and salt concentration cs.D first decreases and then increases as A increases when Ais not large.At large A,D decreases with an increase in A owing to the polyelectrolyte charge reversal caused by the aggregation of ions near it.Meanwhile,g_(3)(t)exhibited intermediate oscillating behavior at moderate A in monovalent cation salt solution.The sliding dynamics of ring can be attributed to the free energy landscape for diffusion.According to the potential of mean force(PMF)of ring chain,we found that our simulation results agreed well with the theoretical results of Lifson-Jackson formula.This study can provide a practical model for the diffusion of charged particles in different dielectric and periodic media,and provides a new perspective for regulating the sliding dynamics of mechanically interlocked molecules in electrolyte solutions.展开更多
Polyelectrolyte solutions are more variable than uncharged macromolecule due to electrical interaction between charged molecules and surrounding counterions.Therefore,the subject of polyelectrolyte solutions has attra...Polyelectrolyte solutions are more variable than uncharged macromolecule due to electrical interaction between charged molecules and surrounding counterions.Therefore,the subject of polyelectrolyte solutions has attracted a wide range of interests in both basic and applied research,and has also been extensively explored.However,the understanding of the molecular dynamics and conformation of polyelectrolytes in solution remains to be deepened,and universal consensus on some key issues have not been reached.Many methods have contributed to solving the above problems in different ways,including dielectric relaxation spectroscopy(DRS).In this perspective,we briefly reviewed the history of dielectric spectroscopic research on polyelectrolyte solution,with emphasis on summarizing our efforts.In particular,we expound the characteristics of DRS and its ability to obtain the internal information of the system of interest.Finally,we evaluate the advantages and limitations of the dielectric method and discussed future prospects of this field.展开更多
Polyelectrolyte brushes(PEBs)are commonly used to modify surface that have attracted great research interest.The dielectric permittivity of the grafted surface is typically significantly different from that of solutio...Polyelectrolyte brushes(PEBs)are commonly used to modify surface that have attracted great research interest.The dielectric permittivity of the grafted surface is typically significantly different from that of solution,which results in surface polarization(SP)effect with a jump of electric field.It is thus important to study how SP alters the PEB’s structure and properties.In this work,the SP effects on PEB structure was studied using a statistical thermodynamic theory.The free energy functional to describe SP effect was constructed by using the image-charge method.Meanwhile,the electrostatic potential was solved from a modified Poisson-Boltzmann equation taking the ion solvation effect into consideration.In the absence of SP,the thickness of PEB exhibited a continuous collapse transition when decreasing the solvent quality.In the presence of SP,the collapse became a jump-like transition.Free energy analysis showed that the long-range Coulombic interaction dominated the transition because of the enhanced counterion condensation in the presence of SP.The theory provides an effective tool to study SP effect on PEBs,and the results explain the underlying physics in PEB collapse transition.展开更多
The counterion-mediated hydrogen bonding(CMHB)is related to the hydrogen bonding between bound counterions and polyelectrolyte chains in polyelectrolyte systems,where the counterions can both electrostatically bind to...The counterion-mediated hydrogen bonding(CMHB)is related to the hydrogen bonding between bound counterions and polyelectrolyte chains in polyelectrolyte systems,where the counterions can both electrostatically bind to the charged groups of polyelectrolyte chains and act as hydrogen bond donors or acceptors to form hydrogen bonds with the hydrogen bond sites associated with polyelectrolyte chains simultaneously.A large number of literatures illustrate that strong polyelectrolytes(SPs)are insensitive to pH,which severely limmits the applications of SPs as smart materials.However,our studies have demonstrated that the CMHB makes SPs pH-responsive.This perspective discusses the mechanism of pH responsiveness of SPs and the pH-tunable properties of SPs,based on the pH-controlled CMHB effect.The future research directions on the pH responsiveness of SPs are also discussed here.It is anticipated that the study of the pH responsiveness of SPs not only will provide a new understanding of the fundamental properties of SPs,but also will greatly expand the applications of SPs in the field of smart materials.展开更多
Titanium dioxide(TiO_(2))hollow nanoparticles present significant potential for photocatalytic applications while their straightforward preparation with precise structure control is still challenging.This work reports...Titanium dioxide(TiO_(2))hollow nanoparticles present significant potential for photocatalytic applications while their straightforward preparation with precise structure control is still challenging.This work reports the approach to preparing tunable hollow TiO_(2) nanospheres by utilization of spherical polyelectrolyte brushes(SPB)as nanoreactors and templates.During the preparation,the evolution of the structure was characterized by small angle X-ray scattering(SAXS),and in combination with dynamic light scattering and transmission electron microscopy.The formation of TiO_(2) shell within the brush(SPB@TiO_(2))is confirmed by the significant increase of the electron density,and its internal structure has been analyzed by fitting SAXS data,which can be influenced by Titanium precursors and ammonia concentration.After calcining SPB@TiO_(2) in a muffle furnace,hollow TiO_(2) nanospheres are produced,and their transition to the anatase crystal form is triggered,as confirmed by X-ray diffraction analysis.Utilizing the advantages of their hollow structure,these TiO_(2) nanospheres exhibit exceptional catalytic degradation efficiency of methylene blue(MB),tetracycline(TC),and 2,4-dichlorophenoxyacetic acid(2,4-D),and also demonstrate excellent recyclability.展开更多
The liquid-liquid phase separation of biopolymers in living cells contains multiple interactions and occurs in a dynamic environment.Resolving the regulation mechanism is still a challenge.In this work,we designed a s...The liquid-liquid phase separation of biopolymers in living cells contains multiple interactions and occurs in a dynamic environment.Resolving the regulation mechanism is still a challenge.In this work,we designed a series of peptides(XXLY)_(6)SSSGSS and studied their complexation and coacervation behavior with single-stranded oligonucleotides.The“X”and“Y”are varied to combine known amounts of charged and non-charged amino acids,together with the introduction of secondary structures and pH responsiveness.Results show that the electrostatic interaction,which is described as charge density,controls both the strength of complexation and the degree of chain relaxation,and thus determines the growth and size of the coacervates.The hydrophobic interaction is prominent when the charges are neutralized.Interestingly,the secondary structures of peptides exhibit profound effect on the morphology of the phases,such as solid phase to liquid phase transition.Our study gains insight into the phase separation under physiological conditions.It is also helpful to create coacervates with desirable structures and functions.展开更多
Polyelectrolytes are charged polymers comprising macromolecules in which substantial portions of the constituent units contain cationic(e.g.,pyridinium,ammonium)or anionic(e.g.,sulfonate,carboxylate)groups,which posse...Polyelectrolytes are charged polymers comprising macromolecules in which substantial portions of the constituent units contain cationic(e.g.,pyridinium,ammonium)or anionic(e.g.,sulfonate,carboxylate)groups,which possess special functions from the features of counterions,such as dissociation to charged species,mechanical stability,phase behavior,etc.Therefore,functional polyelectrolytes have been widely applied in many fields.In this perspective,we present some progresses in the studies of poly(polyoxometalate)s,denoted as poly(POM)s,as a kind of new charged polymers/polyelectrolytes,by covalent bonding between the inorganic polyoxometalate(POM)clusters and the organic polymer chains.According to the distinct positions of POMs in polymer chain and functions of poly(POM)s,they are divided into the following four categories:crosslinked poly(POM);side-chain poly(POM);backbone poly(POM),including poly(POM)-conjugated polymer hybrid and block poly(POM)-polymer;and POM-based covalent organic framework(PCOF).This perspective introduces the synthesis methods of poly(POM)polyelectrolytes and their macromolecular and aggregate structural characteristics,while also focusing on their properties and functions.Their application areas include catalysis,thermal resistance,optical functions,fuel cells and batteries,etc.展开更多
We utilize molecular dynamics simulations to investigate the microstructures of ions and polyelectrolytes in aqueous solutions under external electric fields.By focusing on the multi-body interactions between ionic co...We utilize molecular dynamics simulations to investigate the microstructures of ions and polyelectrolytes in aqueous solutions under external electric fields.By focusing on the multi-body interactions between ionic components and H_(2)O molecules,as well as their responses to the external electric fields,we clarify several nontrivial molecular features of the ionic and polyelectrolyte solutions,such as the solvations of cations and anions,clustering of the ions,and dispersions/aggregations of polyelectrolyte chains,as well as the corresponding responses of H_(2)O molecules in these contexts.Our simulations illustrate the variations in structures of ionic solutions caused by reversing the charge sign of the ions,and elucidate the disparity in structures between anionic and cationic polyelectrolyte solutions in the presence of the external electric fields.This work clarifies the mechanism for the alternations in complex multi-body interactions in aqueous solutions caused by the application electric field,which can contribute to the fundamental understanding of the physical and chemical natures of ion-containing and charged polymeric systems.展开更多
We investigate the solution self-assembly of a mixture of positively charged homopolymers and AB diblock copolymers,in which the A blocks are negatively charged,and the B blocks are neutral.The electrostatic complexat...We investigate the solution self-assembly of a mixture of positively charged homopolymers and AB diblock copolymers,in which the A blocks are negatively charged,and the B blocks are neutral.The electrostatic complexation between oppositely charged polymers drives the formation of many ordered phases.The microstructures and phase diagrams are calculated using self-consistent field theory(SCFT)based on an ion-pair model with an equilibrium constant K to characterize the strength of binding between positively and negatively charged monomers.The effects of the charge ratio,representing the ratio of charges from the homopolymer over all charges from polymers in the system,on the ordered structure are systematically studied,both for hydrophobic and hydrophilic A blocks.The charge ratio plays an important role in determining the phase boundaries in the phase diagram of salt concentration versus polymer concentration.We also provide information about the varying tendency of the domain spacing and core size of the spherical phase when the charge ratio is changed,and the results are in good agreement with experiments.These studies provide a deep understanding of the self-assembled microstructures of oppositely charged diblock copolymer-homopolymer systems.展开更多
Polyelectrolyte complexes(PECs)of hyperbranched(HB)and linear polysaccharides are promising as more effective encapsulation agents compared to PECs formed by linear polysaccharides.We investigated the PECs between the...Polyelectrolyte complexes(PECs)of hyperbranched(HB)and linear polysaccharides are promising as more effective encapsulation agents compared to PECs formed by linear polysaccharides.We investigated the PECs between the HB anionic polysaccharide fucoidan(FUC)and the cationic linear polysaccharide chitosan(CS).The FUC had a molecular weight(MW)of 30×106.The PECs were prepared in three solvents(water,0.01 and 0.1 mol/L acetic acid)with CS of MW of 15,110 and 170 kDa,and deacetylation degrees(DDA)of 70%and 97%.The structures of the PECs and the initial FUC were investigated by multi-angle static and dynamic light scattering.As the FUC contained 18 wt%of—OSO3 groups and 5 wt%of uronic acid units,it was a“strong-weak”copolyanion,so the HB macromolecules of the FUC formed nanogel particles in 0.1 mol/L AcOH and open branched structures in water,as confirmed by the Kratky plots.After mixing the solutions of original components,the PEC structures underwent an equilibration period,the duration of which increased with the MW of CS.As the charge stoichiometry was approached,the PECs shrank;the fractal dimension approached unity,indicating the side-by-side packing of adjacent FUC branches with the help of CS.Secondary aggregation in the vicinity of the charge compensation was hardly observed,as it occurred in a very narrow region.The PEC content at theζ-potential inversion depended on solvents’pH and the DDA of CS.In the extreme case of core-shell PECs in 0.1 mol/L AcOH,obtained by mixing FUC nanogels with the solutions of high MW CS of 97%DDA,the protruding tails of CS formed a positively charged shell in the whole range of FUC content(10 wt%<WFUC<90 wt%).Scanning electron microscopy and atomic force microscopy images of dried samples were discussed in relation to the light scattering results.展开更多
Polyelectrolyte(PE)gels,distinguished by their unique stimuli-responsive swelling behavior,serve as the basis of broad applications,such as artificial muscles and drug delivery.In this work,we present a theoretical mo...Polyelectrolyte(PE)gels,distinguished by their unique stimuli-responsive swelling behavior,serve as the basis of broad applications,such as artificial muscles and drug delivery.In this work,we present a theoretical model to analyze the electrostatics and its contribution to the swelling behavior of PE gels in salt solutions.By minimizing the free energy of PE gels,we obtain two distinct scaling regimes for the swelling ratio at equilibrium with respect to the salt concentration.We compare our predictions for the swelling ratio with experimental measurements,which show excellent agreement.In addition,we employ a finite element method to assess the applicability range of our theoretical model and assumptions.We anticipate that our model will also provide valuable insights into drug adsorption and release,deformation of red blood cells,4D printing and soft robotics,where the underlying mechanism of swelling remains enigmatic.展开更多
The self-consistent field theory(SCFT)was employed to numerically study the interaction and interpenetration between two opposing weak polyelectrolyte(PE)brushes formed by grafting weak PE chains onto the surfaces of ...The self-consistent field theory(SCFT)was employed to numerically study the interaction and interpenetration between two opposing weak polyelectrolyte(PE)brushes formed by grafting weak PE chains onto the surfaces of two long and parallel columns with rectangularshaped cross-section immersed in a salty aqueous solution.The dependences of the brush heights and the average degree of ionization on various system parameters were also investigated.When the brush separation is relatively large compared with the unperturbed brush height,the degree of interpenetration between the two opposing PE brushes was found to increase with increasing grafting density and bulk degree of ionization.The degree of interpenetration also increases with the bulk salt concentration in the osmotic brush regime.Numerical results further revealed that,at a brush separation comparable to the unperturbed brush height,the degree of interpenetration does not increase further with increasing bulk degree of ionization,bulk salt concentration in the osmotic regime and grafting density.The saturation of the degree of interpenetration with these system parameters indicates that the grafted PE chains in the gap between the two columns retract and tilt in order to reduce the unfavorable electrostatic and steric repulsions between the two opposing PE brushes.Based on salt ion concentrations at the midpoint between the two opposing brushes,a quantitative criterion in terms of the unperturbed brush height and Debye screening length was established to determine the threshold value of the brush separation beyond which they are truly independent from each other.展开更多
Polymer density-functional theories(PDFTs)have distinct advantages in the study of polyelectrolyte(PE)systems over experiments and molecular simulations.Here we give an introductory review of some PDFTs recently devel...Polymer density-functional theories(PDFTs)have distinct advantages in the study of polyelectrolyte(PE)systems over experiments and molecular simulations.Here we give an introductory review of some PDFTs recently developed for PE systems.We start with a general formalism of PDFTs and its relation to the widely used polymer self-consistent field theory(SCFT),then explain the various correlations that are neglected in SCFT but can be accounted for in PDFTs,including those due to the excluded-volume interaction and chain connectivity of uncharged polymers,the electrostatic correlations of small ions,and the chain correlations in PEs.We also list some applications of PDFTs for PE systems,and finally give some perspectives on future work.We hope that our review can attract more researchers to apply and further develop PDFTs as a promising class of theoretical and computational tools.展开更多
Bioactive coating of ceramic scaffolds is an effective way to ameliorate osseointegration and attenuate implant-induced inflammatory responses,which should be biocompatible and possess suitable mechani-cal properties ...Bioactive coating of ceramic scaffolds is an effective way to ameliorate osseointegration and attenuate implant-induced inflammatory responses,which should be biocompatible and possess suitable mechani-cal properties to regulate cell adhesion and migration.In this study,a poly(ethylene glycol)diacry-late/tricalcium phosphate(PEGDA/TCP)ceramic scaffold was prepared using SLA-3D printing,and its com-pressive strength was 8.9±1.0 MPa.Chitosan(Chi)and chondroitin sulfate(CS)were assembled on the sur-face of the PEGDA/TCP scaffolds and crosslinked with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide/N-hydroxysuccinimide(EDC/NHS).Scanning electron microscope(SEM),Fourier transform infrared(FTIR),and laser scanning microscope were used to evaluate the surface modification of the PEGDA/TCP scaffolds.Cellu-lar tests showed that polyelectrolyte multilayers(PEMs)promoted cell adhesion and proliferation of osteoblasts relative to unmodified scaffolds.Furthermore,it can be demonstrated that the SLA-3D printed TCP scaffolds could meet the compressive requirements of trabecular bones,and the bioactivity of the bone scaffolds could be effectively improved by combining them with Chi/CS PEM.展开更多
It was found that the interface effects in viscous capillary flow influenced the process of viscosity measurement greatly, and the abnormal viscosity behaviors of polyelectrolytes as well as neutral polymers in dilute...It was found that the interface effects in viscous capillary flow influenced the process of viscosity measurement greatly, and the abnormal viscosity behaviors of polyelectrolytes as well as neutral polymers in dilute solution region were ascribed to interface effect. According to this theory, we have reviewed the previous viscosity data of derivatives of poly-2- vinylpyridine reported by Maclay and Fuoss first. Then, the abnormal viscosity behaviors of a series of sodium polystyrene sulfonate samples with various molecular weights in dilute aqueous solutions were studied further. The solute adsorption behaviors and structural information of polymers have been discussed carefully.展开更多
The authors have investigated the pH and ionic strength response of self-assembled layers formed by adsorption of amphiphilic weak polyelectrolytes. Using the SFA （Surface Forces Apparatus） the authors measured forc...The authors have investigated the pH and ionic strength response of self-assembled layers formed by adsorption of amphiphilic weak polyelectrolytes. Using the SFA （Surface Forces Apparatus） the authors measured force-distance profiles of poly （isoprene）-poly （acrylic acid） block copolymers adsorbed on mica. Also by Atomic Force Microscopy the authors captured single polyelectrolyte molecule adsorbed on a surface. The effect of salt concentration （Cs） and pH upon the height of the brush layers was explored mainly by measuring the forces between two adsorbed polyelectrolyte brushes. At pH = 4 our results are in good agreement with the scaling prediction L0 ∝Cs-1/3 Changing the pH from 4 to 10 causes a remarkable swelling of the polymer layer, but only a weak dependence on salt concentration was detected at the higher pH. This can be attributed to the degree of dissociation, which depends on the local pH value. At low pH the polyelectrolyte chains have a low charge density, while on increasing the pH the degree of dissociation rises, and the increased charge density is followed by swelling of the adsorbed layer. The local concentration of ions in the brush is now greater than that of pH = 4 and approximately equivalent to 0.3 M. So the swelling is only weakly dependent on salt concentration in the range 0.01-1.0 M. The results demonstrate the tunable nature of such self-assembled polyelectroiyte brushes whose height and range of interactions, can be systematically controlled by adjusting the pH and ionic strength of the medium.展开更多
基金supported by the National Natural Science Foundation of China(52375204)Shaanxi Provincial Science and Technology Innovation Team(2024RS-CXTD-63)+4 种基金Xianyang 2023 Key Research and Development Plan(L2023-ZDYF-QYCX-009)the Fundamental Research Funds for the Central Universities(D5000230356)2024“Double First-Class University”Construction Special Fund Project(0604024GH0201332,0604024SH0201332)Zhiyuan Laboratory(NO.ZYL2024007)Horizon Europe Framework Programme(101086071-CUPOLA).
文摘Conductive hydrogels have garnered widespread attention as a versatile class of flexible electronics.Despite considerable advancements,current methodologies struggle to reconcile the fundamental trade-off between high conductivity and effective absorption-dominated electromagnetic interference(EMI)shielding,as dictated by classical impedance matching theory.This study addresses these limitations by introducing a novel synthesis of aramid nanofiber/MXene-reinforced polyelectrolyte hydrogels.Leveraging the unique properties of polyelectrolytes,this innovative approach enhances ionic conductivity and exploits the hydration effect of hydrophilic polar groups to induce the formation of intermediate water.This critical innovation facilitates polarization relaxation and rearrangement in response to electromagnetic fields,thereby significantly enhancing the EMI shielding effectiveness of hydrogels.The electromagnetic wave attenuation capacity of these hydrogels was thoroughly evaluated across both X-band and terahertz band frequencies,with further investigation into the impact of varying water content states-hydrated,dried,and frozen-on their electromagnetic properties.Moreover,the hydrogels exhibited promising capabilities beyond mere EMI shielding;they also served effectively as strain sensors for monitoring human motions,indicating their potential applicability in wearable electronics.This work provides a new approach to designing multifunctional hydrogels,advancing the integration of flexible,multifunctional materials in modern electronics,with potential applications in both EMI shielding and wearable technology.
基金the financial support of the National Natural Science Foundation of China(No.22205165).
文摘Moisture-enabled electricity generation(MEG)has emerged as a promising sustainable energy harvesting technology,comparable to photovoltaics,thermoelectrics,and triboelectrics[1].MEGs generate electricity by converting the chemical potential of moisture into electric energy through interactions with hygroscopic materials and nanostructured interfaces.Unlike solar or thermal harvesters,MEGs operate continuously by utilizing ubiquitous atmospheric moisture,granting them unique spatial and temporal adaptability.Despite nearly a decade of progress and the exploration of diverse material systems for MEG,the overall output power remains significantly limited due to inherently low charge carrier concentrations and restricted ion diffusion fluxes[2].As a result,standalone MEG devices often deliver low and unstable output,limiting practical applications.To enhance performance and versatility,recent efforts have explored hybridization of MEG with other ambient energy sources such as triboelectric or thermoelectric effects.
基金supported by the National Natural Science Foundation of China(Nos.22273112 and 22203100).
文摘Polyelectrolytes(PEs)are polymers carrying ionizable groups along the chain backbone and play an important role in life and environmental sciences,industrial applications and other fields.Due to the complicated topological structure and electrostatic correlations of PEs,PEs exhibit very rich phase behavior and morphologies in both bulk and confined solutions.So far,many theories,simulations and machine learning approaches have been proposed to study the behavior of polyelectrolyte solutions,especially the intrinsic structure-property relationships.In this perspective,from a personal point of view,we present several recent trends in polyelectrolyte solutions.The main themes considered here are accelerated development of sequence-defined polyelectrolyte(SDPE)via artificial intelligence technology,liquid-liquid phase separation in bulk SDPE solutions,adsorption behaviors of SDPE in the vicinity of a single dielectric surface,and surface forces between two charged surfaces mediated by SDPE solutions.
基金support from the National Natural Science Foundation of China(NSFC,22393901,22021001,22272143,22441030)the National Key Research and Development Program(2021YFA1502300)+1 种基金the Fundamental Research Funds for the Central Universities(20720220009)the Natural Science Foundation of Fujian Province,China(Grant No.2024J01213135)。
文摘In this work,we have developed a lignin-derived polymer electrolyte(LSELi),which demonstrates exceptional ionic conductivity of 1.6×10^(-3)S cm^(−1)and a high cation transference number of 0.57 at 25°C.Time of flight secondary ion mass spectrometry(TOF-SIMS)analysis shows that the large-size 1-ethyl-3-methylimidazolium cations(EMIM^(+))can induce the aggregation of the anionic segments in lignosulfonate to reconstruct the three-dimensional(3D)spatial structure of polyelectrolyte,thereby forming a fluent Li^(+)transport 3D network.Dielectric loss spectroscopy further reveals that within this transport network,Li^(+)transport is decoupled from the relaxation of lignosulfonate chain segments,exhibiting characteristics of rapid Li^(+)transport.Furthermore,in-situ distribution of relaxation times analysis indicates that a stable solid electrolyte interface layer is formed at the Li plating interface with LSELi,optimizing the Li plating interface and exhibiting low charge transfer impedance and stable Li plating and stripping.Thus,a substantially prolonged cycling stability and reversibility are obtained in the Li||LSELi||Li battery at 25°C(1800 h at 0.1 mA cm^(−2),0.1 mAh cm^(−2)).At 25°C,the Li||LSELi||LiFePO_(4)cell shows 132 mAh g^(−1)of capacity with 92.7%of retention over 120 cycles at 0.1 mA cm^(−2).
基金supported by the National Natural Science Foundation of China(Nos.22173080,22403062,and22363005)the Jiangxi Provincial Natural Science Foundation(No.20202BABL203015)。
文摘Molecular dynamics simulations were performed to investigate the sliding dynamics of a small charged ring chain along rigid cyclic diblock polyelectrolyte in catenane immersed in salt solution.We found that both the mean-square displacement g_(3)(t)and diffusion coefficient D of ring are influenced by the salt type,electrostatic interaction strength A and salt concentration cs.D first decreases and then increases as A increases when Ais not large.At large A,D decreases with an increase in A owing to the polyelectrolyte charge reversal caused by the aggregation of ions near it.Meanwhile,g_(3)(t)exhibited intermediate oscillating behavior at moderate A in monovalent cation salt solution.The sliding dynamics of ring can be attributed to the free energy landscape for diffusion.According to the potential of mean force(PMF)of ring chain,we found that our simulation results agreed well with the theoretical results of Lifson-Jackson formula.This study can provide a practical model for the diffusion of charged particles in different dielectric and periodic media,and provides a new perspective for regulating the sliding dynamics of mechanically interlocked molecules in electrolyte solutions.
基金supported by the National Natural Science Foundation of China(Nos.21673002,21473012 and 21173025).
文摘Polyelectrolyte solutions are more variable than uncharged macromolecule due to electrical interaction between charged molecules and surrounding counterions.Therefore,the subject of polyelectrolyte solutions has attracted a wide range of interests in both basic and applied research,and has also been extensively explored.However,the understanding of the molecular dynamics and conformation of polyelectrolytes in solution remains to be deepened,and universal consensus on some key issues have not been reached.Many methods have contributed to solving the above problems in different ways,including dielectric relaxation spectroscopy(DRS).In this perspective,we briefly reviewed the history of dielectric spectroscopic research on polyelectrolyte solution,with emphasis on summarizing our efforts.In particular,we expound the characteristics of DRS and its ability to obtain the internal information of the system of interest.Finally,we evaluate the advantages and limitations of the dielectric method and discussed future prospects of this field.
基金supported by the National Natural Science Foundation of China(No.21978079).
文摘Polyelectrolyte brushes(PEBs)are commonly used to modify surface that have attracted great research interest.The dielectric permittivity of the grafted surface is typically significantly different from that of solution,which results in surface polarization(SP)effect with a jump of electric field.It is thus important to study how SP alters the PEB’s structure and properties.In this work,the SP effects on PEB structure was studied using a statistical thermodynamic theory.The free energy functional to describe SP effect was constructed by using the image-charge method.Meanwhile,the electrostatic potential was solved from a modified Poisson-Boltzmann equation taking the ion solvation effect into consideration.In the absence of SP,the thickness of PEB exhibited a continuous collapse transition when decreasing the solvent quality.In the presence of SP,the collapse became a jump-like transition.Free energy analysis showed that the long-range Coulombic interaction dominated the transition because of the enhanced counterion condensation in the presence of SP.The theory provides an effective tool to study SP effect on PEBs,and the results explain the underlying physics in PEB collapse transition.
基金supported by the National Natural Science Foundation of China(Nos.22273098,52033001,22373003 and 22103002)the Fundamental Research Funds for the Central Universities(No.WK2480000007).
文摘The counterion-mediated hydrogen bonding(CMHB)is related to the hydrogen bonding between bound counterions and polyelectrolyte chains in polyelectrolyte systems,where the counterions can both electrostatically bind to the charged groups of polyelectrolyte chains and act as hydrogen bond donors or acceptors to form hydrogen bonds with the hydrogen bond sites associated with polyelectrolyte chains simultaneously.A large number of literatures illustrate that strong polyelectrolytes(SPs)are insensitive to pH,which severely limmits the applications of SPs as smart materials.However,our studies have demonstrated that the CMHB makes SPs pH-responsive.This perspective discusses the mechanism of pH responsiveness of SPs and the pH-tunable properties of SPs,based on the pH-controlled CMHB effect.The future research directions on the pH responsiveness of SPs are also discussed here.It is anticipated that the study of the pH responsiveness of SPs not only will provide a new understanding of the fundamental properties of SPs,but also will greatly expand the applications of SPs in the field of smart materials.
基金funded by the National Key Research and Development Program of China,grant number 2023YFD1700303.
文摘Titanium dioxide(TiO_(2))hollow nanoparticles present significant potential for photocatalytic applications while their straightforward preparation with precise structure control is still challenging.This work reports the approach to preparing tunable hollow TiO_(2) nanospheres by utilization of spherical polyelectrolyte brushes(SPB)as nanoreactors and templates.During the preparation,the evolution of the structure was characterized by small angle X-ray scattering(SAXS),and in combination with dynamic light scattering and transmission electron microscopy.The formation of TiO_(2) shell within the brush(SPB@TiO_(2))is confirmed by the significant increase of the electron density,and its internal structure has been analyzed by fitting SAXS data,which can be influenced by Titanium precursors and ammonia concentration.After calcining SPB@TiO_(2) in a muffle furnace,hollow TiO_(2) nanospheres are produced,and their transition to the anatase crystal form is triggered,as confirmed by X-ray diffraction analysis.Utilizing the advantages of their hollow structure,these TiO_(2) nanospheres exhibit exceptional catalytic degradation efficiency of methylene blue(MB),tetracycline(TC),and 2,4-dichlorophenoxyacetic acid(2,4-D),and also demonstrate excellent recyclability.
基金supported by the National Natural Science Foundation of China(No.21973002).
文摘The liquid-liquid phase separation of biopolymers in living cells contains multiple interactions and occurs in a dynamic environment.Resolving the regulation mechanism is still a challenge.In this work,we designed a series of peptides(XXLY)_(6)SSSGSS and studied their complexation and coacervation behavior with single-stranded oligonucleotides.The“X”and“Y”are varied to combine known amounts of charged and non-charged amino acids,together with the introduction of secondary structures and pH responsiveness.Results show that the electrostatic interaction,which is described as charge density,controls both the strength of complexation and the degree of chain relaxation,and thus determines the growth and size of the coacervates.The hydrophobic interaction is prominent when the charges are neutralized.Interestingly,the secondary structures of peptides exhibit profound effect on the morphology of the phases,such as solid phase to liquid phase transition.Our study gains insight into the phase separation under physiological conditions.It is also helpful to create coacervates with desirable structures and functions.
基金supported by the Natural Science Foundation of Shandong Province of China(No.ZR2023QB278)the National Natural Science Foundation of China(No.92061120).
文摘Polyelectrolytes are charged polymers comprising macromolecules in which substantial portions of the constituent units contain cationic(e.g.,pyridinium,ammonium)or anionic(e.g.,sulfonate,carboxylate)groups,which possess special functions from the features of counterions,such as dissociation to charged species,mechanical stability,phase behavior,etc.Therefore,functional polyelectrolytes have been widely applied in many fields.In this perspective,we present some progresses in the studies of poly(polyoxometalate)s,denoted as poly(POM)s,as a kind of new charged polymers/polyelectrolytes,by covalent bonding between the inorganic polyoxometalate(POM)clusters and the organic polymer chains.According to the distinct positions of POMs in polymer chain and functions of poly(POM)s,they are divided into the following four categories:crosslinked poly(POM);side-chain poly(POM);backbone poly(POM),including poly(POM)-conjugated polymer hybrid and block poly(POM)-polymer;and POM-based covalent organic framework(PCOF).This perspective introduces the synthesis methods of poly(POM)polyelectrolytes and their macromolecular and aggregate structural characteristics,while also focusing on their properties and functions.Their application areas include catalysis,thermal resistance,optical functions,fuel cells and batteries,etc.
基金supported by the Major Science and Technology Projects for Independent Innovation of China FAW Group Co., Ltd. (No. 20220301018GX)the National Natural Science Foundation of China (Nos. 9237210012, 22073094 and 21474109)+2 种基金the Science and Technology Development Program of Jilin Province (Nos. 20240602003RC and 20210402059GH)the State Key Laboratory of Molecular Engineering of Polymers (Fudan University) (No. K2023-08)the Program for Young Scholars in Regional Development of CAS
文摘We utilize molecular dynamics simulations to investigate the microstructures of ions and polyelectrolytes in aqueous solutions under external electric fields.By focusing on the multi-body interactions between ionic components and H_(2)O molecules,as well as their responses to the external electric fields,we clarify several nontrivial molecular features of the ionic and polyelectrolyte solutions,such as the solvations of cations and anions,clustering of the ions,and dispersions/aggregations of polyelectrolyte chains,as well as the corresponding responses of H_(2)O molecules in these contexts.Our simulations illustrate the variations in structures of ionic solutions caused by reversing the charge sign of the ions,and elucidate the disparity in structures between anionic and cationic polyelectrolyte solutions in the presence of the external electric fields.This work clarifies the mechanism for the alternations in complex multi-body interactions in aqueous solutions caused by the application electric field,which can contribute to the fundamental understanding of the physical and chemical natures of ion-containing and charged polymeric systems.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.22073002,51921002 and 22373008).
文摘We investigate the solution self-assembly of a mixture of positively charged homopolymers and AB diblock copolymers,in which the A blocks are negatively charged,and the B blocks are neutral.The electrostatic complexation between oppositely charged polymers drives the formation of many ordered phases.The microstructures and phase diagrams are calculated using self-consistent field theory(SCFT)based on an ion-pair model with an equilibrium constant K to characterize the strength of binding between positively and negatively charged monomers.The effects of the charge ratio,representing the ratio of charges from the homopolymer over all charges from polymers in the system,on the ordered structure are systematically studied,both for hydrophobic and hydrophilic A blocks.The charge ratio plays an important role in determining the phase boundaries in the phase diagram of salt concentration versus polymer concentration.We also provide information about the varying tendency of the domain spacing and core size of the spherical phase when the charge ratio is changed,and the results are in good agreement with experiments.These studies provide a deep understanding of the self-assembled microstructures of oppositely charged diblock copolymer-homopolymer systems.
基金jointly funded by the Russian Science Foundationthe St.-Petersburg Science Foundation(No.23-23-10005)
文摘Polyelectrolyte complexes(PECs)of hyperbranched(HB)and linear polysaccharides are promising as more effective encapsulation agents compared to PECs formed by linear polysaccharides.We investigated the PECs between the HB anionic polysaccharide fucoidan(FUC)and the cationic linear polysaccharide chitosan(CS).The FUC had a molecular weight(MW)of 30×106.The PECs were prepared in three solvents(water,0.01 and 0.1 mol/L acetic acid)with CS of MW of 15,110 and 170 kDa,and deacetylation degrees(DDA)of 70%and 97%.The structures of the PECs and the initial FUC were investigated by multi-angle static and dynamic light scattering.As the FUC contained 18 wt%of—OSO3 groups and 5 wt%of uronic acid units,it was a“strong-weak”copolyanion,so the HB macromolecules of the FUC formed nanogel particles in 0.1 mol/L AcOH and open branched structures in water,as confirmed by the Kratky plots.After mixing the solutions of original components,the PEC structures underwent an equilibration period,the duration of which increased with the MW of CS.As the charge stoichiometry was approached,the PECs shrank;the fractal dimension approached unity,indicating the side-by-side packing of adjacent FUC branches with the help of CS.Secondary aggregation in the vicinity of the charge compensation was hardly observed,as it occurred in a very narrow region.The PEC content at theζ-potential inversion depended on solvents’pH and the DDA of CS.In the extreme case of core-shell PECs in 0.1 mol/L AcOH,obtained by mixing FUC nanogels with the solutions of high MW CS of 97%DDA,the protruding tails of CS formed a positively charged shell in the whole range of FUC content(10 wt%<WFUC<90 wt%).Scanning electron microscopy and atomic force microscopy images of dried samples were discussed in relation to the light scattering results.
基金supported by the National Natural Science Foundation of China(No.12372259).
文摘Polyelectrolyte(PE)gels,distinguished by their unique stimuli-responsive swelling behavior,serve as the basis of broad applications,such as artificial muscles and drug delivery.In this work,we present a theoretical model to analyze the electrostatics and its contribution to the swelling behavior of PE gels in salt solutions.By minimizing the free energy of PE gels,we obtain two distinct scaling regimes for the swelling ratio at equilibrium with respect to the salt concentration.We compare our predictions for the swelling ratio with experimental measurements,which show excellent agreement.In addition,we employ a finite element method to assess the applicability range of our theoretical model and assumptions.We anticipate that our model will also provide valuable insights into drug adsorption and release,deformation of red blood cells,4D printing and soft robotics,where the underlying mechanism of swelling remains enigmatic.
基金supported by the National Natural Science Foundation of China(No.21774067)The Foundation of Key Laboratory of Flexible Electronics of Zhejiang Province(No.2023FE004)C.T.acknowledges the support from K.C.Wong Magna at Ningbo University。
文摘The self-consistent field theory(SCFT)was employed to numerically study the interaction and interpenetration between two opposing weak polyelectrolyte(PE)brushes formed by grafting weak PE chains onto the surfaces of two long and parallel columns with rectangularshaped cross-section immersed in a salty aqueous solution.The dependences of the brush heights and the average degree of ionization on various system parameters were also investigated.When the brush separation is relatively large compared with the unperturbed brush height,the degree of interpenetration between the two opposing PE brushes was found to increase with increasing grafting density and bulk degree of ionization.The degree of interpenetration also increases with the bulk salt concentration in the osmotic brush regime.Numerical results further revealed that,at a brush separation comparable to the unperturbed brush height,the degree of interpenetration does not increase further with increasing bulk degree of ionization,bulk salt concentration in the osmotic regime and grafting density.The saturation of the degree of interpenetration with these system parameters indicates that the grafted PE chains in the gap between the two columns retract and tilt in order to reduce the unfavorable electrostatic and steric repulsions between the two opposing PE brushes.Based on salt ion concentrations at the midpoint between the two opposing brushes,a quantitative criterion in terms of the unperturbed brush height and Debye screening length was established to determine the threshold value of the brush separation beyond which they are truly independent from each other.
基金support for this work provided by the National Natural Science Foundation of China(Nos.22173051 and 21829301).
文摘Polymer density-functional theories(PDFTs)have distinct advantages in the study of polyelectrolyte(PE)systems over experiments and molecular simulations.Here we give an introductory review of some PDFTs recently developed for PE systems.We start with a general formalism of PDFTs and its relation to the widely used polymer self-consistent field theory(SCFT),then explain the various correlations that are neglected in SCFT but can be accounted for in PDFTs,including those due to the excluded-volume interaction and chain connectivity of uncharged polymers,the electrostatic correlations of small ions,and the chain correlations in PEs.We also list some applications of PDFTs for PE systems,and finally give some perspectives on future work.We hope that our review can attract more researchers to apply and further develop PDFTs as a promising class of theoretical and computational tools.
基金supported by National Key Research and Development Project of China(Grant.No.2022YFB4601403)National Natural Science Foundation of China(Grant.No.52175336).
文摘Bioactive coating of ceramic scaffolds is an effective way to ameliorate osseointegration and attenuate implant-induced inflammatory responses,which should be biocompatible and possess suitable mechani-cal properties to regulate cell adhesion and migration.In this study,a poly(ethylene glycol)diacry-late/tricalcium phosphate(PEGDA/TCP)ceramic scaffold was prepared using SLA-3D printing,and its com-pressive strength was 8.9±1.0 MPa.Chitosan(Chi)and chondroitin sulfate(CS)were assembled on the sur-face of the PEGDA/TCP scaffolds and crosslinked with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide/N-hydroxysuccinimide(EDC/NHS).Scanning electron microscope(SEM),Fourier transform infrared(FTIR),and laser scanning microscope were used to evaluate the surface modification of the PEGDA/TCP scaffolds.Cellu-lar tests showed that polyelectrolyte multilayers(PEMs)promoted cell adhesion and proliferation of osteoblasts relative to unmodified scaffolds.Furthermore,it can be demonstrated that the SLA-3D printed TCP scaffolds could meet the compressive requirements of trabecular bones,and the bioactivity of the bone scaffolds could be effectively improved by combining them with Chi/CS PEM.
基金financially supported by the National Natural Science Foundation of China(Nos.50633030 and 51073077)
文摘It was found that the interface effects in viscous capillary flow influenced the process of viscosity measurement greatly, and the abnormal viscosity behaviors of polyelectrolytes as well as neutral polymers in dilute solution region were ascribed to interface effect. According to this theory, we have reviewed the previous viscosity data of derivatives of poly-2- vinylpyridine reported by Maclay and Fuoss first. Then, the abnormal viscosity behaviors of a series of sodium polystyrene sulfonate samples with various molecular weights in dilute aqueous solutions were studied further. The solute adsorption behaviors and structural information of polymers have been discussed carefully.
文摘The authors have investigated the pH and ionic strength response of self-assembled layers formed by adsorption of amphiphilic weak polyelectrolytes. Using the SFA （Surface Forces Apparatus） the authors measured force-distance profiles of poly （isoprene）-poly （acrylic acid） block copolymers adsorbed on mica. Also by Atomic Force Microscopy the authors captured single polyelectrolyte molecule adsorbed on a surface. The effect of salt concentration （Cs） and pH upon the height of the brush layers was explored mainly by measuring the forces between two adsorbed polyelectrolyte brushes. At pH = 4 our results are in good agreement with the scaling prediction L0 ∝Cs-1/3 Changing the pH from 4 to 10 causes a remarkable swelling of the polymer layer, but only a weak dependence on salt concentration was detected at the higher pH. This can be attributed to the degree of dissociation, which depends on the local pH value. At low pH the polyelectrolyte chains have a low charge density, while on increasing the pH the degree of dissociation rises, and the increased charge density is followed by swelling of the adsorbed layer. The local concentration of ions in the brush is now greater than that of pH = 4 and approximately equivalent to 0.3 M. So the swelling is only weakly dependent on salt concentration in the range 0.01-1.0 M. The results demonstrate the tunable nature of such self-assembled polyelectroiyte brushes whose height and range of interactions, can be systematically controlled by adjusting the pH and ionic strength of the medium.
