Developing advanced polymeric materials with enhanced mechanical properties and functionalities has been a long-standing goal in materials science.Recently,supramolecular polymeric materials(SPMs)have drawn increased ...Developing advanced polymeric materials with enhanced mechanical properties and functionalities has been a long-standing goal in materials science.Recently,supramolecular polymeric materials(SPMs)have drawn increased attention due to their unique properties and potential applications in self-healing,shape memory,sensors,and flexible electronics.Here,we develop an ionic cluster-optimized microphase separation strategy to enhance the toughening and energy dissipation capabilities of polydisulfide-based supramolecular polymers.The mechanical properties,including Young's modulus and toughness,are significantly improved by integrating the quadruple H-bonding 2-ureido-4-pyrimidone(UPy)induced microphase separation with iron(III)-to-carboxylate ionic clusters.By combining established chemical approaches with adjustable polymer phase ratios,it is revealed that the synergistic effect of these factors expands the interchain spacing,facilitates the formation of microphase domains,and enhances the tolerance of polythioctic acid-based polymers to external mechanical and thermal stimuli,meeting the practical requirements for industrial plastic applications.Moreover,the UPy-functionalized polymers incorporating iron carboxylate clusters exhibit good one-way shape memory behavior with practical applicability at a relatively low recovery temperature.Our work demonstrates a novel strategy for constructing industrially viable shape memory dynamic SPMs and paves the way for future innovations in developing SPMs.展开更多
The separation of propylene(C_(3)H_(6))and propane(C_(3)H_(8))presents a significant industrial challenge due to their similar molecular dimensions and physicochemical properties.Among various separation methods,molec...The separation of propylene(C_(3)H_(6))and propane(C_(3)H_(8))presents a significant industrial challenge due to their similar molecular dimensions and physicochemical properties.Among various separation methods,molecular sieving emerges as the most promising approach,but it will be significantly compromised at high temperatures due to the significant thermal motion.Here,we report a thermally robust zinc-based metal-organic framework(MOF)that can be synthesized on sub-kilogram scale and achieve exceptional C_(3)H_(6)/C_(3)H_(8) separation performances across a broad temperature range(298–353 K).Unlike conventional MOFs suffering from thermal lattice expansion to give poorer selectivity,this new MOF gives the adsorption capacity of C_(3)H_(6)essentially unchanged and that of C_(3)H_(8) negligible at elevated temperatures,outperforming most state-of-the-art adsorbents,in virtue of multiple hydrogen bonds at the aperture.Column breakthrough experiments confirmed the excellent separation capability,and showed no performance degradation over multi-round adsorption-desorption cycles at 353 K.This study addresses the critical challenge of the trade-off between temperature and selectivity in adsorptive separation,which offers new insights into the design of porous structures for highly effective separation at high temperatures.展开更多
This paper examines a model that combines vortex generators and leading-edge tubercles for controlling the laminar separation bubble(LSB)over an airfoil at low Reynolds numbers(Re).This new concept of passive flow con...This paper examines a model that combines vortex generators and leading-edge tubercles for controlling the laminar separation bubble(LSB)over an airfoil at low Reynolds numbers(Re).This new concept of passive flow control technique utilizing a tubercle and vortex generator(VG)close to the leading edge was analyzed numerically for a NACA0015 airfoil.In this study,the Shear Stress Transport(SST)turbulence model was employed in the numerical modelling.Numerical modelling was completed using the ANSYS-Fluent 18.2 solver.Analyses were conducted to investigate the flow pattern and understand the underlying LSB control phenomena that enabled the new passive flow control method to provide this significant performance benefit.The findings indicated that the new concept of passive flow control technique suppressed the formation of an LSB at the suction surface of the NACA0015 airfoil,resulting in a higher lift coefficient and improved aerodynamic performance.Improvements in LSB dynamics and aerodynamic performance through the passive flow control method lead to increased energy output and enhanced stability.展开更多
With the legislative development,the organic and inorganic composition separation has become the primary requirement for sewer sediment disposal,however the relevant technology has been rarely reported and the driving...With the legislative development,the organic and inorganic composition separation has become the primary requirement for sewer sediment disposal,however the relevant technology has been rarely reported and the driving mechanism was still unclear.In this study,direct disintegration of biopolymers and indirect broken of connection point were investigated on the hydrolysis and component separation.Three typical sewer sediment treatment approaches,i.e.,alkaline,thermal and cation exchange treatments were proposed,which represented the hydrolysis-driving forces of chemical hydrolysis,physical hydrolysis and innovative cation bridging break-age.The results showed that the organic and inorganic separation rates of sewer sediment driven by alkaline,thermal and cation exchange treatments reached 21.26%,23.80%,and 19.56%-48.0%,respectively,compared to 4.43%in control.The secondary structure of proteins was disrupted,transitioning from𝛼α-helix to𝛽β-turn and random coil.Meanwhile,much biopolymers were released from solid to the liquid phase.From thermody-namic perspective,sewer sediment deposition was controlled by short-range interfacial interactions described by extended Derjaguin-Landau-Verwey-Overbeek theory.Additionally,the separation of organic and inorganic components was positively correlated with the thermodynamic parameters(Corr=0.87),highlighted the robust-ness of various driving forces.And the flocculation energy barriers were 2.40(alkaline),1.60 times(thermal),and 4.02–4.97 times(cation exchange)compared to control group.The findings revealed the contrition differ-ence of direct disintegration of gelatinous biopolymers and indirect breakage of composition connection sites in sediment composition separation,filling the critical gaps in understanding the specific mechanisms of sediment biopolymer disintegration and intermolecular connection breakage.展开更多
Vehicle-induced response separation is a crucial issue in structural health monitoring(SHM).This paper proposes a block-wise sliding recursive wavelet transform algorithm to meet the real-time processing requirements ...Vehicle-induced response separation is a crucial issue in structural health monitoring(SHM).This paper proposes a block-wise sliding recursive wavelet transform algorithm to meet the real-time processing requirements of monitoring data.To extend the separation target from a fixed dataset to a continuously updating data stream,a block-wise sliding framework is first developed.This framework is further optimized considering the characteristics of real-time data streams,and its advantage in computational efficiency is theoretically demonstrated.During the decomposition and reconstruction processes,information from neighboring data blocks is fully utilized to reduce algorithmic complexity.In addition,a delay-setting strategy is introduced for each processing window to mitigate boundary effects,thereby balancing accuracy and efficiency.Simulated signal experiments are conducted to determine the optimal delay configuration and to verify the algorithm’s superior performance,achieving a lower Root Mean Square Error(RMSE)and only 0.0249 times the average computational time compared with the original algorithm.Furthermore,strain signals from the Lieshi River Bridge are employed to validate the method.The proposed algorithm successfully separates the static trend from vehicle-induced responses in real time across different sampling frequencies,demonstrating its effectiveness and applicability in real-time bridge monitoring.展开更多
The removal of trace plutonium(Pu)from uranium products and organic wastes during spent nuclear fuel reprocessing remains a critical challenge,resulting in excessive plutonium content in uranium products and waste org...The removal of trace plutonium(Pu)from uranium products and organic wastes during spent nuclear fuel reprocessing remains a critical challenge,resulting in excessive plutonium content in uranium products and waste organic liquid.Currently,most organic ligands with selective separation functions are lipophilic,while research on water-soluble,highly selective ligands is relatively scarce,and there are also few reports on the single crystal of these ligands coordinating with plutonium.Herein,a hydrophilic multiamide ligand,N,N,N′,N″,N″-hexaethyl-nitrilotriacetamide(NTAamideC2),was synthesized and evaluated for its Pu(Ⅳ)back-extraction efficiency under harsh conditions.Systematic experiments revealed that NTAamideC2 achieved>99%Pu(Ⅳ)back-extraction rate within 15 min across a wide nitric acid concentration range(0-5 M),even with elevated dibutyl phosphate(DBP≤20000 ppm).Remarkably,the separation factor(SFPu/U)reached 767 at 1.5 M HNO_(3),demonstrating exceptional selectivity over uranium(Ⅵ).Spectrophotometric titration and DFT calculations confirmed the formation of 1:1 and 1:2 Pu(Ⅳ)-NTAamideC2 complexes,with log β values of 7.42±0.01 and 13.23±0.02,respectively.Single-crystal X-ray diffraction analysis of{[Pu_(2)(H_(2)O)_(2)(NTAamideC2)_(4)](H_(2)O)_(2)(NO_(3))(ClO_(4))_(7)}revealed a nine-coordinated PuO_(7)N_(2)geometry,where two NTAamideC2 molecules bind via six O and two N atoms.Compared to conventional agents(AHA/HSC),NTAamideC2 exhibited superior acid tolerance and selectivity,aligning with the CHON principle for sustainable nuclear waste management.This work provides a robust strategy for Pu(Ⅳ)removal in uranium purification cycles and advances fundamental insights into Pu coordination chemistry,offering significant potential for industrial nuclear fuel reprocessing.展开更多
To develop an efficient filter for removing white blood cells from whole blood,hydrophilic large-pore blended membranes of poly(vinylidene fluoride)(PVDF),polyvinyl pyrrolidone and polyethylene glycol,with good biocom...To develop an efficient filter for removing white blood cells from whole blood,hydrophilic large-pore blended membranes of poly(vinylidene fluoride)(PVDF),polyvinyl pyrrolidone and polyethylene glycol,with good biocompatibility,were prepared using the process of vapor-induced phase separation at various PVDF concentrations.The results demonstrated that at a PVDF mass concentration of 14%,the membrane had increased surface roughness,significantly enhanced hydrophilicity and wettability,and a wetting time of 8 s.The surface roughness of the membrane was also reduced to 31.637 nm.Furthermore,hemolysis rate and protein adsorption tests indicated that the blended membranes possessed excellent biocompatibility.They were reduced to 2.48%and 34.44μg·cm^(−2),respectively.The pore size of the fabricated membrane was relatively large,which reached approximately 8μm respectively,satisfying the filtration requirements.Lastly,the effects of different temperatures and multi-layered filters on leukocyte removal and the retention of red blood cells and platelets from whole blood were evaluated.The results revealed that the leukocyte removal rate was highest at 4℃ and with three membrane layers,the leukocyte removal rate was highest,reaching 98.36%,while the RBC and platelet content remained nearly unchanged compared with the original blood.This study provides a new approach for blood cell separation that is expected to play a significant role in medical fields such as blood transfusion demonstrating great potential for application and innovation.展开更多
Objective:To analyze the impact of maternal-infant separation on the physical and mental state of high-risk pregnancy patients and explore the clinical efficacy of targeted nursing interventions.Methods:A total of 80 ...Objective:To analyze the impact of maternal-infant separation on the physical and mental state of high-risk pregnancy patients and explore the clinical efficacy of targeted nursing interventions.Methods:A total of 80 high-risk pregnancy patients treated in our hospital from January 2023 to January 2024 were selected as the study subjects.These patients were randomly divided into an observation group and a control group(40 cases each)using a random number table.The control group received routine high-risk pregnancy nursing care,while the observation group received specialized maternal-infant separation nursing interventions in addition to routine care.The psychological and physiological states and nursing satisfaction of the two groups were compared before and after the intervention.Results:The SAS scores,SDS scores,and sleep quality scores of the observation group were significantly lower than those of the control group,with statistically significant differences(p<0.05).The incidence of postpartum hemorrhage in the observation group was significantly lower than that in the control group,and the initiation time of lactation was significantly earlier than that in the control group,with both differences being statistically significant(p<0.05).The nursing satisfaction of the observation group was significantly higher than that of the control group(80%vs.32/40),with a statistically significant difference(p<0.05).Conclusion:Maternal-infant separation exacerbates anxiety and depression in high-risk pregnancy patients,reduces sleep quality,increases the risk of postpartum hemorrhage,and delays the initiation of lactation.Specialized nursing interventions for maternal-infant separation can improve the physical and mental state of high-risk pregnancy patients,reduce the incidence of postpartum complications,and enhance nursing satisfaction,making them worthy of clinical application and promotion.展开更多
Conventional electrolytic methods for separating chemically similar lanthanides(Ln)and actinides(An)are limited by thermodynamics and slow reaction kinetics,restricting their efficiency in rare-earth refining and nucl...Conventional electrolytic methods for separating chemically similar lanthanides(Ln)and actinides(An)are limited by thermodynamics and slow reaction kinetics,restricting their efficiency in rare-earth refining and nuclear fuel recycling.Herein,we report an electroextraction and oxidative back-extraction(EOB)strategy utilizing a LiCl-KCl-KAlCl_(4) molten salt that overcomes these limitations by leveraging divergent interfacial reactivity.The EOB process achieves an exceptional separation factor for Ln/An(>1000),while simultaneously increasing the separation rate by at least one order of magnitude.Through in-situ synchrotron radiation X-ray micro-computed tomography(SR-μCT)and X-ray diffraction(SR-XRD),we capture selective oxidation-induced destabilization of Ln-Al alloys while actinides retain phase stability-directly visualizing the electrochemical alloy transition mechanism.This research redefines the separation of f-block elements in molten salt systems and introduces a multimodal approach to investigating transient interfacial phenomena that are usually inaccessible to conventional metallurgical diagnostics under extreme conditions.展开更多
Biochar has been widely recognized as a promising solid CO_(2)adsorbent with economic and ecological benefits.Industrial CO_(2)emissions originate from diverse sources,while the pore structure and chemical functional ...Biochar has been widely recognized as a promising solid CO_(2)adsorbent with economic and ecological benefits.Industrial CO_(2)emissions originate from diverse sources,while the pore structure and chemical functional groups of biochar exhibit varying degrees of influence on CO_(2)adsorption and separation performance under different adsorption conditions.Therefore,exploring the matching relationship between the physicochemical properties of biochar and its adsorption and separation performance at different adsorption conditions is essential for the development and optimization of carbon-based adsorbents.This study selected the high-performance extreme gradient boosting(XGB)algorithm from various algorithms and utilized it to develop CO_(2),N_(2),CH_(4)adsorption prediction models.Based on this,coupled prediction models were developed for CO_(2)/N_(2)and CO_(2)/CH_(4)adsorption selectivity.Furthermore,feature importance and partial dependence analysis were performed using SHAP values.The results indicate that during CO_(2)adsorption,the influence of the pore structure of biochar outweighs that of its chemical composition.Specifically,the pore structure of 0.4–0.6 nm is the most important property influencing CO_(2)adsorption at low and medium pressure(0–0.6 bar),and the pore structure of 0.6–0.8 nm,as well as the specific surface area contribute the most at high pressure(0.6–1 bar).During CO_(2)selective separation,the CO_(2)/N_(2)mixture is primarily separated through the selective adsorption of CO_(2)by nitrogen functional groups.In contrast,for CO_(2)/CH_(4)mixtures,pore structure<1 nm plays a more critical role in determining adsorption selectivity.In addition,molecular simulation studies further revealed the adsorption filling mechanisms of CO_(2)molecules within different pore sizes and functional groups.Finally,nitrogen-doped biochar was synthesized using de-alkalize lignin as the precursor,KOH as the activating agent,and urea as the nitrogen dopant.CO_(2),N_(2),and CH_(4)isothermal adsorption experiments were conducted,and the experimental results confirmed that the developed prediction models exhibit high accuracy(R^(2)>0.9).展开更多
Developing a chiral material as versatile and universal chiral stationary phase(CSP) for chiral separation in diverse chromatographic techniques simultaneously is of great significance.In this study,we demonstrated fo...Developing a chiral material as versatile and universal chiral stationary phase(CSP) for chiral separation in diverse chromatographic techniques simultaneously is of great significance.In this study,we demonstrated for the first time that a chiral metal-organic cage(MOC),[Zn_(6)M_(4)],as a universal chiral recognition material for both multi-mode high-performance liquid chromatography(HPLC) and capillary gas chromatography(GC) enantioseparation.Two novel HPLC CSPs with different bonding arms(CSP-A with a cationic imidazolium bonding arm and CSP-B with an alkyl chain bonding arm) were prepared by clicking of functionalized chiral MOC [Zn_(6)M_(4)] onto thiolated silica via thiol-ene click chemistry.Meanwhile,a capillary GC column statically coated with the chiral MOC [Zn_(6)M_(4)] was also fabricated.The results showed that the chiral MOC exhibits excellent enantioselectivity not only in normal phase HPLC(NP-HPLC) and reversed phase(RP-HPLC) but also in GC,and various racemates were well separated,including alcohols,diols,esters,ketones,ethers,amines,and epoxides.Importantly,CSP-A and CSP-B are complementary to commercially available Chiralcel OD-H and Chiralpak AD-H columns in enantioseparation,which can separate some racemates that could not be or could not well be separated by the two widely used commercial columns,suggesting the great potential of the two prepared CSPs in enantioseparation.This work reveals that the chiral MOC is potential versatile chiral recognition materials for both HPLC and GC,and also paves the way to expand the potential applications of MOCs.展开更多
Due to complex ion-ion and ion-membrane interactions, creating innovative membrane structures to acquire favorable ion mixing effect and high separation performance remains a big challenge. Herein, we design covalent ...Due to complex ion-ion and ion-membrane interactions, creating innovative membrane structures to acquire favorable ion mixing effect and high separation performance remains a big challenge. Herein, we design covalent organic framework(COF) scaffold membrane with gate-lane nanostructure for efficient Li^(+)/Mg^(2+) separation. COF nanosheets, serving as the scaffold, are intercalated by polyethyleneimine(PEI) to form the permeating layer. Subsequently, PEI on the surface reacts with 1,4-phenylene diisocyanate to form the polyurea gating layer. The gating layer, bearing tailored smaller pore size,affords high rejection to co-ions(Mg^(2+)) and thus high Li^(+)/Mg^(2+) selectivity. The permeating layer, with asymmetric charge and spatial nanostructure for creating individual lanes of Li^(+) and Cl~-, facilitates Li^(+) transport and thus high Li^(+) permeability. The optimum COF scaffold membrane exhibits the permeance of 11.5 L m^(-2) h^(-1)/bar^(-1) and true selectivity of 231.9 with Li^(+) enrichment of 120.2% at the Mg^(2+)/Li^(+) mass ratio of 50, exceeding the ideal selectivity of 80.5 and outperforming all ever-reported positively charged nanofiltration membranes. Our work may stimulate the further thinking about how to design the hierarchical membrane structure to achieve favorable ion mixing effect and break the membrane permeability-selectivity trade-off in chemical separations.展开更多
The accumulation and circulation of carbon and hydrogen contribute to the chemical evolution of ice giant planets.Species separation and diamond precipitation have been reported in carbon-hydrogen systems and have bee...The accumulation and circulation of carbon and hydrogen contribute to the chemical evolution of ice giant planets.Species separation and diamond precipitation have been reported in carbon-hydrogen systems and have been verified by static and shock compression experiments.Nevertheless,the dynamic formation processes underlying these phenomena remain insufficiently understood.In combination with a deep learning model,we demonstrate that diamonds form through a three-step process involving dissociation,species separation,and nucleation processes.Under shock conditions of 125 GPa and 4590 K,hydrocarbons decompose to give hydrogen and low-molecular-weight alkanes(CH_(4) and C_(2)H_(6)),which escape from the carbon chains,resulting in C/H species separation.The remaining carbon atoms without C-H bonds accumulate and nucleate to form diamond crystals.The process of diamond growth is associated with a critical nucleus size at which the dynamic energy barrier plays a key role.These dynamic processes of diamond formation provide insight into the establishment of a model for the evolution of ice giant planets.展开更多
Water scarcity,exacerbated by organic micropollutant contamination and climate change,necessitates energy-efficient,eco-friendly purification technologies.Membrane separation has emerged as a transformative solution,o...Water scarcity,exacerbated by organic micropollutant contamination and climate change,necessitates energy-efficient,eco-friendly purification technologies.Membrane separation has emerged as a transformative solution,outperforming energyintensive processes,such as distillation.As highlighted in Nature,traditional chemical separations—dominated by distillation—consume 10%-15%of global energy,whereas advanced membrane technologies can reduce energy use by up to 90%.展开更多
The microphase-separating behaviors of two types of star-diblock copolymers （Ax）4（By）4 and （A^Bg）4 in thin films are studied using the simulation technique of dissipative particle dynamics. A variety of ordered ...The microphase-separating behaviors of two types of star-diblock copolymers （Ax）4（By）4 and （A^Bg）4 in thin films are studied using the simulation technique of dissipative particle dynamics. A variety of ordered mesostructures have been observed and the simulated phase diagrams show obvious symmetries for the （Ax）4（By）a films and asymmetries for the （AxBy）4 films, besides, it is easier for the （Ax）4（By）4 than for the （A^By）4 to carry out microphase separation under the same conditions, which has been recognized in bulk and can be ascribed to the structural difference between the two types of star copolymers. There are some correspondences between the mesostructures formed in the film and those formed in bulk at the same composition fraction. Decreasing the thickness of film and strengthening the A-B repulsion both help the mesostructures enhance the degree of order. Composition fraction dependences of the mean-square radius of gyration in the two types of star copolymer films are almost contrary, which can be attributed to the differences in their respective structures. These findings can provide a guide to designing novel microstructures involving star-diblock copolymers via geometrical confinement.展开更多
Solid-state electrolytes(SSEs)with high ionic conductivity,mechanical stability,and high thermal stability,as well as the stringent requirement of application in high-temperature fuel cells and lithium-ion batteries i...Solid-state electrolytes(SSEs)with high ionic conductivity,mechanical stability,and high thermal stability,as well as the stringent requirement of application in high-temperature fuel cells and lithium-ion batteries is receiving increasing attention.Polymer nanocomposites(PNCs),combining the advantages of inorganic materials with those of polymeric materials,offer numerous opportunities for SSEs design.In this work,we report a facile and general one-pot approach based on polymerization-induced microphase separation(PIMS)to generate PNCs with bi-continuous microphases.This synthetic strategy transforms a homogeneous liquid precursor consisting of polyoxometalates(POMs,H_(3)PW_(12)O_(40),Li_(7)[V_(15)O_(36)(CO_(3))]),poly(ethylene glycol)(PEG)macro-chain-transfer agent,styrene and divinylbenzene monomers,into a robust and transparent monolith.The resulting POMs are uniformly dispersed in the PEG block(PEG/POM)to form a conducting pathway that successfully realizes the effective transfer of protons and lithium ions,while the highly cross-linked polystyrene domains(P(S-co-DVB))as mechanical support provide outstanding mechanical properties and thermal stability.As the POM loading ratio up to 35 wt%,the proton conductivity of nanocomposite reaches as high as 5.99×10^(-4) S/cm at 100℃ in anhydrous environment,which effectively promotes proton transfer under extreme environments.This study broadens the application of fuel cells and lithium-ion batteries in extreme environments.展开更多
Incorporating antibacterial agent into biomimetic coating inspired by natural organisms with micronano structure surface has generated more interest for antifouling applications.In this work,poly(dimethylsiloxane)(PDM...Incorporating antibacterial agent into biomimetic coating inspired by natural organisms with micronano structure surface has generated more interest for antifouling applications.In this work,poly(dimethylsiloxane)(PDMS)-based triblock copolymers and sub-20 nm nanoparticles Ag and heterogeneous Fe_(3)O_(4)-coated Ag(Fe_(3)O_(4)@Ag)were used to construct microphase separation topography with oriented copolymer blocks structure.The artificial surface was verified by atomic force microscopy and scanning electron microscopy images.Meanwhile,the surface exhibited relative stable hydrophobic property,which was demonstrated by the water contact angle and dynamic air-bubble contact angle measurements.Consequently,after immersed in BSA solution 24 h and 720 h,the actual BSA absorption amount of the surface with Fe_(3)O_(4)@Ag nanoparticles was as low as 10%and 27%that of the initial BSA amount,respectively.Moreover,the surface also showed remarkable antibacterial performance,which effectively suppressed the growth rate of Escherichia coli.The strategy of constructing the flexible micro p hase separation structure by introducing heterogeneous inorganic antibacterial nanoparticles into a block copolymer substrate opens up a new way to create an antifouling surface coating.展开更多
The phase behavior of a well-defined poly(methyl methacrylate)- b- polystyrene block copolymer was studied by transmission electron microscope. The results show that a microphase transition may have occurred in the co...The phase behavior of a well-defined poly(methyl methacrylate)- b- polystyrene block copolymer was studied by transmission electron microscope. The results show that a microphase transition may have occurred in the copolymer film. A kind of lamellae and an ordered bicontinuous double-diamond morphology are observed clearly. The lamellar morphology reveals a larger period of about 400 nm.展开更多
We investigated the effects of molecular weight and film thickness on the crystallization and microphase separation in semicrystalline block copolymer polystyrene-block-poly（L-lactic acid） （PS-b-PLLA） thin films, ...We investigated the effects of molecular weight and film thickness on the crystallization and microphase separation in semicrystalline block copolymer polystyrene-block-poly（L-lactic acid） （PS-b-PLLA） thin films, at the early stage of film evolution （when Tg 〈 T 〈 TODT） by in situ hot stage atomic force microscopy. For PS-b-PLLA 1 copolymer which had lower molecular weight and higher PLLA fraction, diffusion-controlled break-out crystallization started easily. For PS-b-PLLA 2 with higher molecular weight, crystallization in nanometer scales occurs in local area. After melting of the two copolymer films, islands were observed at the film surface： PS-b-PLLA 1 film was in a disordered phase mixed state while PS-b-PLLA 2 film formed phase-separated lamellar structure paralleling to the substrate. Crystallization-melting and van der Waals forces drove the island formation in PS-b-PLLA 1 film. Film thickness affected the crystallization rate. Crystals grew very slowly in much thinner film of PS-b-PLLA 1 and remained almost unchanged at long time annealing. The incompatibility between PS and PLLA blocks drove the film fluctuation which subsequently evolved into spinodal-like morphology.展开更多
A series of mixed, random cylindrical brush copolymers bearing polystyrene（PS） and poly（ε-caprolactone）（PCL） side chains were synthesized via the combination of ring-opening polymerization（ROP） and atom trans...A series of mixed, random cylindrical brush copolymers bearing polystyrene（PS） and poly（ε-caprolactone）（PCL） side chains were synthesized via the combination of ring-opening polymerization（ROP） and atom transfer radical polymerization（ATRP）. These novel cylindrical brush copolymers have been characterized by means of nuclear magnetic resonance（NMR） spectroscopy, gel permeation chromatography（GPC） and differential scanning calorimetry（DSC）. It was found that the mikto-armed cylindrical brush copolymers were microphase-separated in bulks and that the morphologies were dependent on the mass ratios of PS to PCL side chains. One of the cylindrical brush copolymers was employed to incorporate into epoxy thermoset to investigate effect of the mikto-armed cylindrical brush architecture on the reaction-induced microphase separation behavior. Depending on the concentration of the cylindrical brush in epoxy, the thermosets can display the morphologies with the spherical, worm-like and lamellar PS microdomains dispersing in continuous thermosetting matrices.展开更多
基金supported by the National Natural Science Foundation of China(No.22375063)Science and Technology Commission of Shanghai Municipality(No.23JC140170O)the Fundamental Research Funds for the Central Universities.
文摘Developing advanced polymeric materials with enhanced mechanical properties and functionalities has been a long-standing goal in materials science.Recently,supramolecular polymeric materials(SPMs)have drawn increased attention due to their unique properties and potential applications in self-healing,shape memory,sensors,and flexible electronics.Here,we develop an ionic cluster-optimized microphase separation strategy to enhance the toughening and energy dissipation capabilities of polydisulfide-based supramolecular polymers.The mechanical properties,including Young's modulus and toughness,are significantly improved by integrating the quadruple H-bonding 2-ureido-4-pyrimidone(UPy)induced microphase separation with iron(III)-to-carboxylate ionic clusters.By combining established chemical approaches with adjustable polymer phase ratios,it is revealed that the synergistic effect of these factors expands the interchain spacing,facilitates the formation of microphase domains,and enhances the tolerance of polythioctic acid-based polymers to external mechanical and thermal stimuli,meeting the practical requirements for industrial plastic applications.Moreover,the UPy-functionalized polymers incorporating iron carboxylate clusters exhibit good one-way shape memory behavior with practical applicability at a relatively low recovery temperature.Our work demonstrates a novel strategy for constructing industrially viable shape memory dynamic SPMs and paves the way for future innovations in developing SPMs.
基金supported by the National Natural Science Foundation of China(22475240,22090061,22488101)the State Key Laboratory of Catalysis(2024SKL-A-010)。
文摘The separation of propylene(C_(3)H_(6))and propane(C_(3)H_(8))presents a significant industrial challenge due to their similar molecular dimensions and physicochemical properties.Among various separation methods,molecular sieving emerges as the most promising approach,but it will be significantly compromised at high temperatures due to the significant thermal motion.Here,we report a thermally robust zinc-based metal-organic framework(MOF)that can be synthesized on sub-kilogram scale and achieve exceptional C_(3)H_(6)/C_(3)H_(8) separation performances across a broad temperature range(298–353 K).Unlike conventional MOFs suffering from thermal lattice expansion to give poorer selectivity,this new MOF gives the adsorption capacity of C_(3)H_(6)essentially unchanged and that of C_(3)H_(8) negligible at elevated temperatures,outperforming most state-of-the-art adsorbents,in virtue of multiple hydrogen bonds at the aperture.Column breakthrough experiments confirmed the excellent separation capability,and showed no performance degradation over multi-round adsorption-desorption cycles at 353 K.This study addresses the critical challenge of the trade-off between temperature and selectivity in adsorptive separation,which offers new insights into the design of porous structures for highly effective separation at high temperatures.
基金the Scientific Research Projects Unit of Erciyes University under contract no:FDS-2022-11532 and FOA-2025-14773.
文摘This paper examines a model that combines vortex generators and leading-edge tubercles for controlling the laminar separation bubble(LSB)over an airfoil at low Reynolds numbers(Re).This new concept of passive flow control technique utilizing a tubercle and vortex generator(VG)close to the leading edge was analyzed numerically for a NACA0015 airfoil.In this study,the Shear Stress Transport(SST)turbulence model was employed in the numerical modelling.Numerical modelling was completed using the ANSYS-Fluent 18.2 solver.Analyses were conducted to investigate the flow pattern and understand the underlying LSB control phenomena that enabled the new passive flow control method to provide this significant performance benefit.The findings indicated that the new concept of passive flow control technique suppressed the formation of an LSB at the suction surface of the NACA0015 airfoil,resulting in a higher lift coefficient and improved aerodynamic performance.Improvements in LSB dynamics and aerodynamic performance through the passive flow control method lead to increased energy output and enhanced stability.
基金supported by Shaanxi Key Research and Development Program(No.2024SF-YBXM-546)the National Natural Science Foundation of China(No.52470161)the State Key Laboratory of Pollution Control and Resource Reuse Foundation(No.PCRRF21007).
文摘With the legislative development,the organic and inorganic composition separation has become the primary requirement for sewer sediment disposal,however the relevant technology has been rarely reported and the driving mechanism was still unclear.In this study,direct disintegration of biopolymers and indirect broken of connection point were investigated on the hydrolysis and component separation.Three typical sewer sediment treatment approaches,i.e.,alkaline,thermal and cation exchange treatments were proposed,which represented the hydrolysis-driving forces of chemical hydrolysis,physical hydrolysis and innovative cation bridging break-age.The results showed that the organic and inorganic separation rates of sewer sediment driven by alkaline,thermal and cation exchange treatments reached 21.26%,23.80%,and 19.56%-48.0%,respectively,compared to 4.43%in control.The secondary structure of proteins was disrupted,transitioning from𝛼α-helix to𝛽β-turn and random coil.Meanwhile,much biopolymers were released from solid to the liquid phase.From thermody-namic perspective,sewer sediment deposition was controlled by short-range interfacial interactions described by extended Derjaguin-Landau-Verwey-Overbeek theory.Additionally,the separation of organic and inorganic components was positively correlated with the thermodynamic parameters(Corr=0.87),highlighted the robust-ness of various driving forces.And the flocculation energy barriers were 2.40(alkaline),1.60 times(thermal),and 4.02–4.97 times(cation exchange)compared to control group.The findings revealed the contrition differ-ence of direct disintegration of gelatinous biopolymers and indirect breakage of composition connection sites in sediment composition separation,filling the critical gaps in understanding the specific mechanisms of sediment biopolymer disintegration and intermolecular connection breakage.
基金the support of the Major Science and Technology Project of Yunnan Province,China(Grant No.202502AD080007)the National Natural Science Foundation of China(Grant No.52378288)。
文摘Vehicle-induced response separation is a crucial issue in structural health monitoring(SHM).This paper proposes a block-wise sliding recursive wavelet transform algorithm to meet the real-time processing requirements of monitoring data.To extend the separation target from a fixed dataset to a continuously updating data stream,a block-wise sliding framework is first developed.This framework is further optimized considering the characteristics of real-time data streams,and its advantage in computational efficiency is theoretically demonstrated.During the decomposition and reconstruction processes,information from neighboring data blocks is fully utilized to reduce algorithmic complexity.In addition,a delay-setting strategy is introduced for each processing window to mitigate boundary effects,thereby balancing accuracy and efficiency.Simulated signal experiments are conducted to determine the optimal delay configuration and to verify the algorithm’s superior performance,achieving a lower Root Mean Square Error(RMSE)and only 0.0249 times the average computational time compared with the original algorithm.Furthermore,strain signals from the Lieshi River Bridge are employed to validate the method.The proposed algorithm successfully separates the static trend from vehicle-induced responses in real time across different sampling frequencies,demonstrating its effectiveness and applicability in real-time bridge monitoring.
基金supported by the China Institute of Atomic Energy。
文摘The removal of trace plutonium(Pu)from uranium products and organic wastes during spent nuclear fuel reprocessing remains a critical challenge,resulting in excessive plutonium content in uranium products and waste organic liquid.Currently,most organic ligands with selective separation functions are lipophilic,while research on water-soluble,highly selective ligands is relatively scarce,and there are also few reports on the single crystal of these ligands coordinating with plutonium.Herein,a hydrophilic multiamide ligand,N,N,N′,N″,N″-hexaethyl-nitrilotriacetamide(NTAamideC2),was synthesized and evaluated for its Pu(Ⅳ)back-extraction efficiency under harsh conditions.Systematic experiments revealed that NTAamideC2 achieved>99%Pu(Ⅳ)back-extraction rate within 15 min across a wide nitric acid concentration range(0-5 M),even with elevated dibutyl phosphate(DBP≤20000 ppm).Remarkably,the separation factor(SFPu/U)reached 767 at 1.5 M HNO_(3),demonstrating exceptional selectivity over uranium(Ⅵ).Spectrophotometric titration and DFT calculations confirmed the formation of 1:1 and 1:2 Pu(Ⅳ)-NTAamideC2 complexes,with log β values of 7.42±0.01 and 13.23±0.02,respectively.Single-crystal X-ray diffraction analysis of{[Pu_(2)(H_(2)O)_(2)(NTAamideC2)_(4)](H_(2)O)_(2)(NO_(3))(ClO_(4))_(7)}revealed a nine-coordinated PuO_(7)N_(2)geometry,where two NTAamideC2 molecules bind via six O and two N atoms.Compared to conventional agents(AHA/HSC),NTAamideC2 exhibited superior acid tolerance and selectivity,aligning with the CHON principle for sustainable nuclear waste management.This work provides a robust strategy for Pu(Ⅳ)removal in uranium purification cycles and advances fundamental insights into Pu coordination chemistry,offering significant potential for industrial nuclear fuel reprocessing.
基金The National Key Research and Development Program of China(2020YFC0862903)Supported by Jiangsu Future Membrane Technology Innovation Center(BM2021804)National Foreign Expert Program(H20240294).
文摘To develop an efficient filter for removing white blood cells from whole blood,hydrophilic large-pore blended membranes of poly(vinylidene fluoride)(PVDF),polyvinyl pyrrolidone and polyethylene glycol,with good biocompatibility,were prepared using the process of vapor-induced phase separation at various PVDF concentrations.The results demonstrated that at a PVDF mass concentration of 14%,the membrane had increased surface roughness,significantly enhanced hydrophilicity and wettability,and a wetting time of 8 s.The surface roughness of the membrane was also reduced to 31.637 nm.Furthermore,hemolysis rate and protein adsorption tests indicated that the blended membranes possessed excellent biocompatibility.They were reduced to 2.48%and 34.44μg·cm^(−2),respectively.The pore size of the fabricated membrane was relatively large,which reached approximately 8μm respectively,satisfying the filtration requirements.Lastly,the effects of different temperatures and multi-layered filters on leukocyte removal and the retention of red blood cells and platelets from whole blood were evaluated.The results revealed that the leukocyte removal rate was highest at 4℃ and with three membrane layers,the leukocyte removal rate was highest,reaching 98.36%,while the RBC and platelet content remained nearly unchanged compared with the original blood.This study provides a new approach for blood cell separation that is expected to play a significant role in medical fields such as blood transfusion demonstrating great potential for application and innovation.
文摘Objective:To analyze the impact of maternal-infant separation on the physical and mental state of high-risk pregnancy patients and explore the clinical efficacy of targeted nursing interventions.Methods:A total of 80 high-risk pregnancy patients treated in our hospital from January 2023 to January 2024 were selected as the study subjects.These patients were randomly divided into an observation group and a control group(40 cases each)using a random number table.The control group received routine high-risk pregnancy nursing care,while the observation group received specialized maternal-infant separation nursing interventions in addition to routine care.The psychological and physiological states and nursing satisfaction of the two groups were compared before and after the intervention.Results:The SAS scores,SDS scores,and sleep quality scores of the observation group were significantly lower than those of the control group,with statistically significant differences(p<0.05).The incidence of postpartum hemorrhage in the observation group was significantly lower than that in the control group,and the initiation time of lactation was significantly earlier than that in the control group,with both differences being statistically significant(p<0.05).The nursing satisfaction of the observation group was significantly higher than that of the control group(80%vs.32/40),with a statistically significant difference(p<0.05).Conclusion:Maternal-infant separation exacerbates anxiety and depression in high-risk pregnancy patients,reduces sleep quality,increases the risk of postpartum hemorrhage,and delays the initiation of lactation.Specialized nursing interventions for maternal-infant separation can improve the physical and mental state of high-risk pregnancy patients,reduce the incidence of postpartum complications,and enhance nursing satisfaction,making them worthy of clinical application and promotion.
基金supported by the National Science Fund for Distinguished Young Scholars(21925603)the National Natural Science Foundation of China(22306185)the China Postdoctoral Science Foundation(2023M732032)。
文摘Conventional electrolytic methods for separating chemically similar lanthanides(Ln)and actinides(An)are limited by thermodynamics and slow reaction kinetics,restricting their efficiency in rare-earth refining and nuclear fuel recycling.Herein,we report an electroextraction and oxidative back-extraction(EOB)strategy utilizing a LiCl-KCl-KAlCl_(4) molten salt that overcomes these limitations by leveraging divergent interfacial reactivity.The EOB process achieves an exceptional separation factor for Ln/An(>1000),while simultaneously increasing the separation rate by at least one order of magnitude.Through in-situ synchrotron radiation X-ray micro-computed tomography(SR-μCT)and X-ray diffraction(SR-XRD),we capture selective oxidation-induced destabilization of Ln-Al alloys while actinides retain phase stability-directly visualizing the electrochemical alloy transition mechanism.This research redefines the separation of f-block elements in molten salt systems and introduces a multimodal approach to investigating transient interfacial phenomena that are usually inaccessible to conventional metallurgical diagnostics under extreme conditions.
基金supported by the Fundamental Research Funds for the Central Universities(No.2025JC008)the National Natural Science Foundation of China(grant number 52176105)+2 种基金the Science and Technology Project of Hebei Education Department-China(BJK2022063)the Hebei Natural Science Foundation-China(grant number E2025502038)the Funding Program for Cultivating Innovative Abilities of Graduate Students in Hebei Province of China(CXZZBS2025184).
文摘Biochar has been widely recognized as a promising solid CO_(2)adsorbent with economic and ecological benefits.Industrial CO_(2)emissions originate from diverse sources,while the pore structure and chemical functional groups of biochar exhibit varying degrees of influence on CO_(2)adsorption and separation performance under different adsorption conditions.Therefore,exploring the matching relationship between the physicochemical properties of biochar and its adsorption and separation performance at different adsorption conditions is essential for the development and optimization of carbon-based adsorbents.This study selected the high-performance extreme gradient boosting(XGB)algorithm from various algorithms and utilized it to develop CO_(2),N_(2),CH_(4)adsorption prediction models.Based on this,coupled prediction models were developed for CO_(2)/N_(2)and CO_(2)/CH_(4)adsorption selectivity.Furthermore,feature importance and partial dependence analysis were performed using SHAP values.The results indicate that during CO_(2)adsorption,the influence of the pore structure of biochar outweighs that of its chemical composition.Specifically,the pore structure of 0.4–0.6 nm is the most important property influencing CO_(2)adsorption at low and medium pressure(0–0.6 bar),and the pore structure of 0.6–0.8 nm,as well as the specific surface area contribute the most at high pressure(0.6–1 bar).During CO_(2)selective separation,the CO_(2)/N_(2)mixture is primarily separated through the selective adsorption of CO_(2)by nitrogen functional groups.In contrast,for CO_(2)/CH_(4)mixtures,pore structure<1 nm plays a more critical role in determining adsorption selectivity.In addition,molecular simulation studies further revealed the adsorption filling mechanisms of CO_(2)molecules within different pore sizes and functional groups.Finally,nitrogen-doped biochar was synthesized using de-alkalize lignin as the precursor,KOH as the activating agent,and urea as the nitrogen dopant.CO_(2),N_(2),and CH_(4)isothermal adsorption experiments were conducted,and the experimental results confirmed that the developed prediction models exhibit high accuracy(R^(2)>0.9).
基金supported by the National Natural Science Foundation of China (Nos.22064020,22364022,and 22174125)the Applied Basic Research Foundation of Yunnan Province (Nos.202101AT070101 and 202201AT070029)。
文摘Developing a chiral material as versatile and universal chiral stationary phase(CSP) for chiral separation in diverse chromatographic techniques simultaneously is of great significance.In this study,we demonstrated for the first time that a chiral metal-organic cage(MOC),[Zn_(6)M_(4)],as a universal chiral recognition material for both multi-mode high-performance liquid chromatography(HPLC) and capillary gas chromatography(GC) enantioseparation.Two novel HPLC CSPs with different bonding arms(CSP-A with a cationic imidazolium bonding arm and CSP-B with an alkyl chain bonding arm) were prepared by clicking of functionalized chiral MOC [Zn_(6)M_(4)] onto thiolated silica via thiol-ene click chemistry.Meanwhile,a capillary GC column statically coated with the chiral MOC [Zn_(6)M_(4)] was also fabricated.The results showed that the chiral MOC exhibits excellent enantioselectivity not only in normal phase HPLC(NP-HPLC) and reversed phase(RP-HPLC) but also in GC,and various racemates were well separated,including alcohols,diols,esters,ketones,ethers,amines,and epoxides.Importantly,CSP-A and CSP-B are complementary to commercially available Chiralcel OD-H and Chiralpak AD-H columns in enantioseparation,which can separate some racemates that could not be or could not well be separated by the two widely used commercial columns,suggesting the great potential of the two prepared CSPs in enantioseparation.This work reveals that the chiral MOC is potential versatile chiral recognition materials for both HPLC and GC,and also paves the way to expand the potential applications of MOCs.
基金financial support from the National Natural Science Foundation of China (22338011, 22378299)Hainan Province Science and Technology Special Fund (ZDYF2025SHFZ025)+1 种基金Ningbo Key Research and Development Project (2022Z121)the China Postdoctoral Science Foundation (2025M771194)。
文摘Due to complex ion-ion and ion-membrane interactions, creating innovative membrane structures to acquire favorable ion mixing effect and high separation performance remains a big challenge. Herein, we design covalent organic framework(COF) scaffold membrane with gate-lane nanostructure for efficient Li^(+)/Mg^(2+) separation. COF nanosheets, serving as the scaffold, are intercalated by polyethyleneimine(PEI) to form the permeating layer. Subsequently, PEI on the surface reacts with 1,4-phenylene diisocyanate to form the polyurea gating layer. The gating layer, bearing tailored smaller pore size,affords high rejection to co-ions(Mg^(2+)) and thus high Li^(+)/Mg^(2+) selectivity. The permeating layer, with asymmetric charge and spatial nanostructure for creating individual lanes of Li^(+) and Cl~-, facilitates Li^(+) transport and thus high Li^(+) permeability. The optimum COF scaffold membrane exhibits the permeance of 11.5 L m^(-2) h^(-1)/bar^(-1) and true selectivity of 231.9 with Li^(+) enrichment of 120.2% at the Mg^(2+)/Li^(+) mass ratio of 50, exceeding the ideal selectivity of 80.5 and outperforming all ever-reported positively charged nanofiltration membranes. Our work may stimulate the further thinking about how to design the hierarchical membrane structure to achieve favorable ion mixing effect and break the membrane permeability-selectivity trade-off in chemical separations.
基金supported by the National Natural Science Foundation of China(Grant Nos.12534013,12047561,and 12104507)the Science and Technology Innovation Program of Hunan Province(Grant Nos.2025ZYJ001 and 2021RC4026)the National University of Defense Technology Research Fund Project.
文摘The accumulation and circulation of carbon and hydrogen contribute to the chemical evolution of ice giant planets.Species separation and diamond precipitation have been reported in carbon-hydrogen systems and have been verified by static and shock compression experiments.Nevertheless,the dynamic formation processes underlying these phenomena remain insufficiently understood.In combination with a deep learning model,we demonstrate that diamonds form through a three-step process involving dissociation,species separation,and nucleation processes.Under shock conditions of 125 GPa and 4590 K,hydrocarbons decompose to give hydrogen and low-molecular-weight alkanes(CH_(4) and C_(2)H_(6)),which escape from the carbon chains,resulting in C/H species separation.The remaining carbon atoms without C-H bonds accumulate and nucleate to form diamond crystals.The process of diamond growth is associated with a critical nucleus size at which the dynamic energy barrier plays a key role.These dynamic processes of diamond formation provide insight into the establishment of a model for the evolution of ice giant planets.
文摘Water scarcity,exacerbated by organic micropollutant contamination and climate change,necessitates energy-efficient,eco-friendly purification technologies.Membrane separation has emerged as a transformative solution,outperforming energyintensive processes,such as distillation.As highlighted in Nature,traditional chemical separations—dominated by distillation—consume 10%-15%of global energy,whereas advanced membrane technologies can reduce energy use by up to 90%.
文摘The microphase-separating behaviors of two types of star-diblock copolymers （Ax）4（By）4 and （A^Bg）4 in thin films are studied using the simulation technique of dissipative particle dynamics. A variety of ordered mesostructures have been observed and the simulated phase diagrams show obvious symmetries for the （Ax）4（By）a films and asymmetries for the （AxBy）4 films, besides, it is easier for the （Ax）4（By）4 than for the （A^By）4 to carry out microphase separation under the same conditions, which has been recognized in bulk and can be ascribed to the structural difference between the two types of star copolymers. There are some correspondences between the mesostructures formed in the film and those formed in bulk at the same composition fraction. Decreasing the thickness of film and strengthening the A-B repulsion both help the mesostructures enhance the degree of order. Composition fraction dependences of the mean-square radius of gyration in the two types of star copolymer films are almost contrary, which can be attributed to the differences in their respective structures. These findings can provide a guide to designing novel microstructures involving star-diblock copolymers via geometrical confinement.
基金supported by National Natural Science Foundation of China(Nos.21961142018,22101086 and 51873067)Natural Science Foundation of Guangdong Province(Nos.2021A1515012024 and 2021A1515010271)。
文摘Solid-state electrolytes(SSEs)with high ionic conductivity,mechanical stability,and high thermal stability,as well as the stringent requirement of application in high-temperature fuel cells and lithium-ion batteries is receiving increasing attention.Polymer nanocomposites(PNCs),combining the advantages of inorganic materials with those of polymeric materials,offer numerous opportunities for SSEs design.In this work,we report a facile and general one-pot approach based on polymerization-induced microphase separation(PIMS)to generate PNCs with bi-continuous microphases.This synthetic strategy transforms a homogeneous liquid precursor consisting of polyoxometalates(POMs,H_(3)PW_(12)O_(40),Li_(7)[V_(15)O_(36)(CO_(3))]),poly(ethylene glycol)(PEG)macro-chain-transfer agent,styrene and divinylbenzene monomers,into a robust and transparent monolith.The resulting POMs are uniformly dispersed in the PEG block(PEG/POM)to form a conducting pathway that successfully realizes the effective transfer of protons and lithium ions,while the highly cross-linked polystyrene domains(P(S-co-DVB))as mechanical support provide outstanding mechanical properties and thermal stability.As the POM loading ratio up to 35 wt%,the proton conductivity of nanocomposite reaches as high as 5.99×10^(-4) S/cm at 100℃ in anhydrous environment,which effectively promotes proton transfer under extreme environments.This study broadens the application of fuel cells and lithium-ion batteries in extreme environments.
基金financially supported by the National Natural Science Foundation of China(Nos.51706166 and 51773163)the Joint Funds of the Equipment Pre-Research of Ministry of Education of China(No.6141A02022225)+1 种基金Sanya Science and Education Innovation Park of Wuhan University of Technology(2020KF0025)the Fundamental Research Funds for the Central Universities(WUT:2020III038GX)。
文摘Incorporating antibacterial agent into biomimetic coating inspired by natural organisms with micronano structure surface has generated more interest for antifouling applications.In this work,poly(dimethylsiloxane)(PDMS)-based triblock copolymers and sub-20 nm nanoparticles Ag and heterogeneous Fe_(3)O_(4)-coated Ag(Fe_(3)O_(4)@Ag)were used to construct microphase separation topography with oriented copolymer blocks structure.The artificial surface was verified by atomic force microscopy and scanning electron microscopy images.Meanwhile,the surface exhibited relative stable hydrophobic property,which was demonstrated by the water contact angle and dynamic air-bubble contact angle measurements.Consequently,after immersed in BSA solution 24 h and 720 h,the actual BSA absorption amount of the surface with Fe_(3)O_(4)@Ag nanoparticles was as low as 10%and 27%that of the initial BSA amount,respectively.Moreover,the surface also showed remarkable antibacterial performance,which effectively suppressed the growth rate of Escherichia coli.The strategy of constructing the flexible micro p hase separation structure by introducing heterogeneous inorganic antibacterial nanoparticles into a block copolymer substrate opens up a new way to create an antifouling surface coating.
文摘The phase behavior of a well-defined poly(methyl methacrylate)- b- polystyrene block copolymer was studied by transmission electron microscope. The results show that a microphase transition may have occurred in the copolymer film. A kind of lamellae and an ordered bicontinuous double-diamond morphology are observed clearly. The lamellar morphology reveals a larger period of about 400 nm.
基金supported by the National Natural Science Foundation of China(Nos.20621401,50773080, 20834005)the Ministry of Science and Technology of China(No.2009CB930603)
文摘We investigated the effects of molecular weight and film thickness on the crystallization and microphase separation in semicrystalline block copolymer polystyrene-block-poly（L-lactic acid） （PS-b-PLLA） thin films, at the early stage of film evolution （when Tg 〈 T 〈 TODT） by in situ hot stage atomic force microscopy. For PS-b-PLLA 1 copolymer which had lower molecular weight and higher PLLA fraction, diffusion-controlled break-out crystallization started easily. For PS-b-PLLA 2 with higher molecular weight, crystallization in nanometer scales occurs in local area. After melting of the two copolymer films, islands were observed at the film surface： PS-b-PLLA 1 film was in a disordered phase mixed state while PS-b-PLLA 2 film formed phase-separated lamellar structure paralleling to the substrate. Crystallization-melting and van der Waals forces drove the island formation in PS-b-PLLA 1 film. Film thickness affected the crystallization rate. Crystals grew very slowly in much thinner film of PS-b-PLLA 1 and remained almost unchanged at long time annealing. The incompatibility between PS and PLLA blocks drove the film fluctuation which subsequently evolved into spinodal-like morphology.
基金financially supported by the National Natural Science Foundation of China(Nos.51133003,21274091 and 21774078)the Shanghai Synchrotron Radiation Facility under the projects(Nos.10sr0260 and 10sr0126)
文摘A series of mixed, random cylindrical brush copolymers bearing polystyrene（PS） and poly（ε-caprolactone）（PCL） side chains were synthesized via the combination of ring-opening polymerization（ROP） and atom transfer radical polymerization（ATRP）. These novel cylindrical brush copolymers have been characterized by means of nuclear magnetic resonance（NMR） spectroscopy, gel permeation chromatography（GPC） and differential scanning calorimetry（DSC）. It was found that the mikto-armed cylindrical brush copolymers were microphase-separated in bulks and that the morphologies were dependent on the mass ratios of PS to PCL side chains. One of the cylindrical brush copolymers was employed to incorporate into epoxy thermoset to investigate effect of the mikto-armed cylindrical brush architecture on the reaction-induced microphase separation behavior. Depending on the concentration of the cylindrical brush in epoxy, the thermosets can display the morphologies with the spherical, worm-like and lamellar PS microdomains dispersing in continuous thermosetting matrices.
