最新刊期
卷 ， 期 10 ， 2016
- 摘要：Precisely manipulating small amounts of liquids has been widely applied in industry,ranging from biomedical devices to liquid transfer.Currently,direct light-driven manipulation of liquids,especially those triggered by light-induced capillary forces has drawn an increasing attention,because it requires neither special optical set-up nor complex microfabrication steps.However,the capillary force arising from wettability gradient is too small to overcome the effect of contact line pinning,and the motion is thus limited to specific liquids with a relatively short distance,simple linear trajectories,and low speed,Here,Yu et al. at Fudan University reported a new strategy to precisely manipulate liquids by photo-induced asymmetric deformation of tubular microactuators,which is a novel principle to induce capillary forces.These microactuators exhibit the unique capabilities to propel a wide diversity of liquids over a long distance with desirable velocity and controllable direction.Application in areas such as micro-opto-mechanical systems and optofluidics is highly anticipated.关键词：Controlled liquid motion;Liquid crystalline polymer;Photodeformation;Actuators
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发布时间：2021-03-19
Research Highlights
- 摘要：Wearable electronics has recently attracted great attentions regarding their flexibility,light weight and integratability.However,with the rapid development of wearable electronics,some knotty while urgent problems appear in the energy supply for them.For example,conventional planar energy devices with inferior flexibility are unable to conformally attach to the irregular substrates,besides their poor breathability and wet permeability.Such problems have severely restricted the progress of wearable electronics and other related research fields.A general and effective strategy to tackle abovementioned problems is designing energy devices into a fiber format.Although the supplied energy of single fiber-shaped energy device is still limited,these fiber-shaped power systems can be easily woven into textiles to realize high energy outputs.Meanwhile,energy textiles indicate many promising features such as the ability of conformally attaching to irregular substrates,e.g.,human body,breathability and wet permeability,which can effectively meet the requirements in the advancement of wearable electronics.Fiber-shaped energy devices can be divided into two categories including energy harvesting and energy storage.Energy harvesting devices are mainly comprised of dye-sensitized solar cells,polymer solar cells and perovskite solar cells; while energy storage devices contains supercapacitors,lithium-ion batteries,lithium-air batteries,zinc-air batteries and aluminum-air batteries,etc.For practical applications,energy harvesting and storage devices are usually integrated to realize a self-powering functionality.This review article emphatically introduces the history,the state-of-the-art and the remaining challenge of fiber-shaped energy harvesting and storage devices.Firstly,the available fiber electrodes are described with a focus on the advancement of carbon nanotube fibers that simultaneously demonstrate high mechanical,electrical and electrochemical properties.Secondly,a variety of fiber-shaped energy harvesting and storage as well as their integrated devices are carefully discussed.Thirdly,the recent development in making fiber-shaped energy devices into power textiles is briefly presented.The main directions in their further advancement are highlighted at end.关键词：Fiber-shaped;Solar cell;Lithium-ion battery;Supercapacitor;Integration
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发布时间：2021-03-19 - 摘要：Microbial infection is always a serious challenge to human health,especially with the emergency of drug-resistant bacteria and fungi such as methicillin-resistant S.aureus (MRSA) and fluconazole-resistant C.albicans. Conventional antibiotics are inevitably susceptible to antimicrobial resistance,therefore,it is urgent to develop new type of antimicrobial agents that are active against existing drug-resistant bacteria and fungi and are less susceptible for pathogens to develop antimicrobial resistance.Host defense peptide (HDP) that exists naturally in almost all forms of lives and demonstrates broad spectrum antimicrobial activity and low susceptibility to antimicrobial resistance has been widely studied in recent years to develop new types of antimicrobial agents in combating antimicrobial resistance.The application of HDP itself is limited by its low stability or high susceptibility to proteolysis and its only moderate antimicrobial activity compared to clinical antimicrobial drugs.Intense work has been done in developing mimics of HDP to acquire improved stability and optimized antimicrobial activity.Nylon-3 polymers (poly-β-peptides) belong to one of the representative HDP-mimicking antimicrobial polymers.Nylon-3 polymers are generally composed by one hydrophilic/cationic subunit and one hydrophobic subunit at varied ratio to mimic two key structure characteristics of HDP: positive charges and amphiphilicity.By optimizing the terminal functional group and polymer length,varying chemical structure of subunits,exploring the optimized subunit combination,and carefully tuning ratio of subunits within polymer chains,we are able to find nylon-3 polymers that demonstrate potent and selective activities against multiple strains of drug-resistant bacteria including MRSA.Using C.difficile as a model,nylon-3 displays dual functions by killing C.difficile vegetative cells directly and preventing the outgrowth of spore to vegetative cells.Nylon-3 also demonstrates potent activity against multiple strains of fungi,including the most common human fungal pathogen C.albicans,that are resistant to fluconazole and even amphotericin B.When applied to complicated and robust biofilm system,nylon-3 can efficiently inhibit the formation of fungal biofilms and kill persister cells within mature fungal biofilms.It is noteworthy that neither bacteria nor fungi display antimicrobial resistance against nylon-3.These findings imply the potential of nylon-3 polymers to battle with antimicrobial resistance and their possible application as novel antimicrobial agents for variable applications.关键词：Antimicrobial resistance;HDP;Nylon-3;Antibacterial;Antifungal
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发布时间：2021-03-19 - 摘要：Recent advances in surface-initiated polymer brushes and specific applications in various research fields are reviewed,the development of surface-initiated atom radical polymerization (SI-ATRP) is highlighted.The general surface modification method is described in detail to realize functional modification on almost all substrates.The combination of the surface-initiated polymerization with other soft lithography techniques,e.g.,micro-contacting printing enables the easy surface functionalization with various surface morphologies such as pattern and gradient.The fundamental mechanistic and synthetic features of SI-ATRP are discussed and some new techniques particularly external-stimuli mediated catalytic and initiation systems are highlighted,including electrochemistry,chemical reducing agents and photochemistry,which have many potential applications in fields such as lubrication,anti-fouling and so on.These methods have solved problems occurring in traditional SI-ATRP,such as inert atmosphere protection,poor controllability,difficulty to recycle monomers,and single modification of substrates.Besides,polymer brush with micrometer scale prepared by using anodic aluminium oxide as a template create multi-scale structures on surfaces.Applications of polymer brush are reviewed mainly in three aspects in this review.(1) Smart actuation:external-stimuli responsive polymer brushes coated substrates can be used as a smart actuator due to the conformation changes of the polymer chains when surrounding environment changes,for example,performing the worm-like movements.(2) Bio-lubrication:polymer brushes have been used as effective lubricating materials on surfaces and the frictional coefficient can be regulated by changing the solvent conditions.(3) Antifouling:Polyelectrolyte brush grafted substrates have been found many applications in biological fields such as antifouling coatings,a series of high performance,low toxicity marine antifouling materials have been developed by taking the advantages of the synergistic effect of the unique surface compositions and structures of polymer brushes.In all,newly developed external stimuli regulated surface-initiated ATRP methods are presented to show how they can be advantageously used to produce multi-functional polymer brushes,which have been widely used as advanced coatings to modify surface properties.关键词：Polymer brush;Surface modification;Atom transfer radical polymerization;External stimulus
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发布时间：2021-03-19
Feature Articles
- 摘要：The search for sustainable resource for polymers production have been obtained much attentions due to the over exploration of fossil resources and environment problems arisen from the use of petroleum based polymeric materials.The modern biorefinery produced a spectrum of biobased chemicals,which can be further upgraded into polymeric monomers for polymer synthesis.This review summarized the latest progress in the synthesis of biobased polymeric monomers from renewable resources such as carbohydrates,lignocellulose and plan oils.According to their structure,those biobased polymeric monomers can be categorised into aliphatic monomers and aromatic monomers including acids,diols,furyl and vanillic monomers.Various strategies,such as catalytic process and fementaion process,were compared in terms of selectivity,yield and feasibility of target biobased monomers.Those biobased monomers can be directly employed as feedstock to prepare biobased polymers,such as polyesters,polyamides,polycarbonates,polyurethanes and polyethers.Besides,both the traditional and novel polymerization processes can be adopted to prepare biobased polymers,such as catalyst free melt condensation,radical polymerization,photocuring process,proton transfer polymerization and enzymatic polycondensations.The influence of various heating methods,catalyst loading,mole ratio,reaction time and temperature to prepare biobased polymers were compared.Those biobased polymers exhibit excellent mechanical and thermal properties and promising properties such as shape memory effect,self-healing properties and bacteria clearing effect,which revealed great potential to replace the petroleum based polymers.Finally,the future development of bio-based polymers has also discussed.关键词：Catalytic biorefinery;Bio-based monomers;Bio-based polymers;Thermal properties;Mechanical properties
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发布时间：2021-03-19
Reviews
- 摘要：An Aryl palladium complex was synthesized by oxidative addition of aryl bromide-containing orange emissive group (OG-Br) to Pd(PCy3)2.The complex is thermally stable in air and can initiate the polymerization of AB-type fluorene monomer at elevated temperature to get polyfluorene with defined aryl end group.Similar conjugated polymers can also be prepared by employing the aryl palladium complexes in situ generated from OG-Br/Pd(0)-species as initiators.Among them,with P(o-tol)3 or N-heterocyclic carbene as the ancillary ligand,catalyst-transfer polymerization of AB-type fluorene monomers can be achieved at room temperature.The complex ligated by N-heterocyclic carbene shows better activity in the catalyst-transfer polymerization,which offer the polyfluorene with high molecular weight of up to 7.48×104.MALDI-TOF mass spectra confirm that the polymers bear the orange emissive group derived from the aryl complex at one end and a Br/H atom at the other end.Photoluminescence (PL) spectra of the polymers show dominant blue emission from the polyfluorene backbone.In contrast,electroluminescence (EL) spectra exhibit orange or white emission,respectively,resulting from a difference of the molecular weight.With the number average molecular weight (Mn) of 7.48×104,the polymer emits pure white light with simultaneous blue and orange emission and CIE coordinates of (0.31,0.32).关键词：Catalyst-transfer polymerization;Aryl palladium complexes;Polyfluorene;Photoluminescence;Electroluminescence
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发布时间：2021-03-19 - 摘要：Polystyrene-based (PS-AC) fluorescent microspheres were prepared by reaction of polystyrene (PS) microspheres with acetyl chloride through Friedel-Crafts acylation.FTIR analysis showed that acetyl group was successfully coupled onto PS microspheres surface through covalent bond.The fluorescent phenomenon of these microspheres was induced by the new conjugate system between benzene ring and substituent group.To confirm the emission mechanism,p-ethylacetophenone was synthesized by reaction of ethyl benzene with acetyl chloride.Fluorescence emission spectra revealed that a strong broad emission was observed between 400 nm to 600 nm upon excitation from 350 nm to 400 nm in both spectra of p-ethylacetophenone and the fluorescent microspheres.Compared with PS microspheres,ethylbenzene and acetyl chloride,both PS-AC and p-ethylacetophenone exhibited a new broad absorption peak ranging from 300 nm to 400 nm in ultraviolet spectrum.These changes confirmed that new conjugated structure,generated through Friedel-Crafts acylation,can convert ultraviolet absorbed by novel conjugated system into visible fluorescence.These results indicated that fluorescence phenomenon of modified PS microspheres was induced by the conjugative effect between benzene ring and carbonyl group.关键词：Polystyrene-based fluorescent microspheres;Friedel-Crafts acylation;Luminescence mechanism;π-π Conjugation
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发布时间：2021-03-19 - 摘要：Introduced cross metathesis which has been applied widely by organic chemists and polymer technologists as a green and convenient method for degradation of industrial polybutadiene rubber (PB) with high molecular weight and polydispersity index ( Mn=6.6×104,PDI=5.2).Reactions were performed using Grubbs 2nd catalyst with several symmetrical olefins including cis-1,4-dichloro-2-butene (DCB),cis-1,4-diacetoxy-2-butene (DAB),dimethyl maleate (DMM) and diethyl maleate (DEM) as chain transfer agents (CTAs).Mn and PDI of telechelic oligomers were measured by gel permeation chromatography (GPC).And the structures and properties were determined by nuclear magnetic resonance spectroscopy (1H-NMR,13C-NMR),Fourier transform infrared spectroscopy (FTIR) and liquid chromatography-mass spectrometer (LC-MS).It was shown that Mn and PDI of telechelic oligomers could be tuned by using different types of monomers as CTAs.Well-defined oligomers with controllable molecular weights ranging from 230 to 4800 and polydispersity indices ranging from 1.09 to 2.82 were realized by changing molar ratios of [PB]/[CTA],[PB]/[catalyst],as well as reaction time.When DAB was introduced as a CTA,Mn of the product decreased to 330 with the molar ratio of [PB]/[DAB]=2:1 and [PB]/[catalyst]=1000:1.Increasing molar ratio of [PB]/[DAB] to 1:1,an almost complete degradation procedure could be reached within a few hours.A new compound with the melting point of 9.37℃ bonded with end acetoxy groups,containing only one butadiene repeating unit,was obtained by Column Chromatograph.Mn of the new compound was 230 determined by 1H-NMR end group analyses,which was perfectly consistent with calculated theoretical value.Furthermore,13C-NMR and LC-MS analyses confirmed the structure of the new compound.When using DMM and DEM as CTAs,Mn of the oligomers were above 1800.The low reactivities of DMM and DEM compared with DCB and DAB in the metathesis reaction could be explained by the formation of non-productive complex between carbonyl oxygen and Ru center that impeded the reaction.关键词：Cross metathesis;Polybutadiene rubber;Degradation;Ruthenium catalyst;Telechelic oligomers
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发布时间：2021-03-19 - 摘要：Pamidronate was conjugated to Brij78 to prepare a novel surfactant Pa-Brij78. Using Pa-Brij78 as emulsifier and stabilizer,PLGA(OVA) nanoparticles with a negative charge were prepared by a water-oil-water double emulsion method. Calcium phosphate coated PLGA(OVA) nanoparticles were fabricated by a co-precipitation method. Toll like receptor ligand CpG was then coated on the surface of the nanoparticles to form CpG/CaP/PLGA(OVA),a novel type of drug-loaded core-shell nanoparticles. The nanoparticles were characterized by Dynamic light scattering (DLS) particle size analyzer,scanning electron microscopy (SEM),transmission electron microscopy (TEM) and X-ray diffraction. The loading capacity and encapsulation efficiency of OVA and CpG were determined. The results of SEM and TEM showed PLGA(OVA) nanoparticles had spherical shape with smooth and even surface,while CaP/PLGA(OVA) nanoparticles were spherical but their surface was rough and irregular due to uneven distribution of calcium phosphate. The coated shell of calcium phosphate was Ca3(PO4)2 as confirmed by X-ray diffraction analysis. Average loading efficiency of OVA was 5% when encapsulation efficiency of OVA was above 80%. Average loading efficiency of CpG was 0.47% when average encapsulation efficiency of CpG was 89%.关键词：Biodegradable polymer;Calcium phosphate;Core-shell structure;Composite drug loaded nanoparticles
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发布时间：2021-03-19 - 摘要：Biodegradable polyurethane-acrylate (PUA) was synthesized via UV-curing of hydroxyl terminated polyurethane acrylate oligomers,which were based on PLLA-diols (PLLA),1,6-hexamethylene diisocyanate (HDI) and hydroxyethyl methyl acrylate (HEMA).PLLA was synthesized by ring opening polymerization of L-lactide (L-LA) initialized by 1,4-butanediol (BDO).PUA oligomers were characterized by NMR and GPC.Their morphological,hydrophilic and mechanical characteristics were inverstigated using DSC,TGA,DMA,contact angle and swelling analysis.The results showed that,with increasing PLLA length,Tg of PUA increased,while PUA hydrophilicity and crosslink density were reduced.The tensile strength of PLLA500-HDI was 7.6 MPa that met the requirement of the mechanical properties for biomaterials.The degradation experiment indicated that increasing PLLA length lowered PUA degradation rate.The weight loss of PLLA500-HDI was 15.8%,the highest in the three polymers.PLLA2000-HDI showed the lowest degradation rate,which may be related to its microstructure.ATR analysis showed that the peak at 3364 cm-1 (N-H) for the degraded film was broadened and the C=O peak (ester and urethane) was sharpened,which indicated the hydrolysis of ester and urethane bonds in the main chain of PUAs.TGA measurement indicated that thermal stability of degraded PLLA500/PLLA1000-HDI was weakened,while PLLA2000-HDI was more stable.SEM of PLLA500-HDI showed crack and holes and the phase separation was observed on the surface of PLLA2000-HDI.Cell culture on PUA materials indicated that they supported the binding of hASCs.Therefore these PUA materials are biocompatible and have potential to be used in hard tissue engineering.关键词：Polylactide;Polyurethane acrylate;UV-curable;Biodegradable;Biocompatible
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发布时间：2021-03-19 - 摘要：A copolymer poly(curcumin)-ss-b-poly(2-(diethylamino)ethylmethacrylate)-poly{N-[2-(methacryloyloxy)ethyl]-N,N-diethyl-N-(3-sulfopropyl)-ammonium} (Cur-DA-ssPDEA-PS) was synthesized with the combination of atom radical transfer polymerization (ATRP) and conjugation and by sulfonation.Molecular structure of the copolymer was confirmed by 1H-NMR and FTIR.Thermophysical properties of the copolymer were determined by DSC.Cur-DA-ssPDEA-PS micelles were formed by solvent evaporation using poly(zwitterionic sulfobetaines) as hydrophilic shell,poly(curcumin) as hydrophobic core,and DEA as pH sensitive content and disulfide as redox responsive linkage.Critical micelle concentration (CMC) of the copolymer in water was estimated using pyrene as a hydrophobic fluorescence probe.Dynamic light scattering (DLS) measurement was performed to determine the micellar size and distribution.Micelle morphology was observed by scanning electron microscopy (SEM).CMC obtained was about 10-3 mg/mL,revealing that the micelles were stable.The micelle diameters were all below 200 nm with a narrow size distribution.There existed a buffer platform in pH titration curve and the micelle sizes changed when pH varying from 7.4 to 5.0.pH responsivity of the micelles was confirmed by these results.When treated by 10 mmol/L glutathione (GSH),the micelles were damaged and aggregated,indicating a reduced micelle responsivity.The higher drug loading than PCL-ss-PDEA-PS indicated improvement of hydrophobic drug encapsulation by introduction of curcumins.关键词：pH/Redox dual-sensitive copolymer;Micelles;Drug delivery carrier;Sulfobetaines;Curcumin
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发布时间：2021-03-19 - 摘要：A novel active difluoro sulfone monomer,3,3'-bis(phenoxyphenyl)-4,4'-difluorodiphenyl sulfone,was successfully synthesized through free-radical substitution and Suzuki coupling reactions using 4,4'-difluorodiphenyl sulfone and N-bromosuccinimide (NBS) as starting materials.Then it was employed to prepare a series of poly(arylene ether sulfone)s (PAES-xx) with 4,4'-difluorodiphenyl sulfone and 4,4'-dihydroxybenzophenone via nucleophilic polycondensation reaction.Poly(arylene ether sulfone)s proton exchange membranes (SPAES-xx) were obtained by mild post-sulfonation reaction and solution casting.The structures and properties of these membranes were investigated.The results showed that the SPAES-xx membranes displayed moderate water absorption and good dimensional stability,and the highest proton conductivity of membranes reached 0.16 S/cm at 80℃.Moreover,these membranes showed good thermal stability and mechanical properties.The onset weight loss temperatures of SPAES-xx were approximately 250℃.They had tensile strengths of 29.5~42.0 MPa,tensile modulus of 0.62~1.23 GPa,and elongations to break from 9.0% to 31.9%.Excellent comprehensive properties of SPAES-xx membranes were mainly ascribed to the introduction of side-chain sulfonated structure and the formation of well defined hydrophilic/hydrophobic phase separation structure.关键词：Side-chain type;Poly(arylene ether sulfone)s;Sulfonation;Proton conductivity;Phase separation
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发布时间：2021-03-19 - 摘要：Understanding the interactions between polymer-nanoparticle conjugates and lipid membrane is important for optimization of their bio-functions.Here the coarse-grained molecular dynamics simulations are performed to investigate the behaviour of terminal-modified PAMAM dendrimers in aqueous solution and their interactions with membrane.MARTINI force field was used for C60,PAMAM dendrimer,and DPPC/DPPG lipids.It was found that after C 60 molecules grafting,the radius of gyration of the PAMAM dendrimer in aqueous solution decreased monotonically with the number of C60 grafted due to hydrophobicity of C60 molecules.The cluster behaviour of C60s changed the structure of flexible PAMAM molecules of the third generation.However,the shape of modified PAMAM only showed a slight deviation from the non-modified one.After interacting with lipid membrane,the size did not monotonously change with the increase in terminal C60 molecules.The shape of the PAMAM molecules changed from sphere-like to ellipsoid-like (the shape factor changed approximately from 0.015 to 0.06).This was because C60 molecules penetrated into the lipid membrane due to the hydrophobic interaction,which was demonstrated by calculation of density profile of lipid heads and C60 molecules.The penetration induced the improvement of membrane permeability characterized by a decrease in local thickness of the membrane.关键词：Dendrimers;Fullerene;Bio-membrane;Surface modification;Computer simulations
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发布时间：2021-03-19 - 摘要：Carboxylated styrene-butadiene rubber/nanosilica (XSBR/A200) composites with an extraodinarily wide range of A200 loading (0-300 phr) were prepared by absorption mixing. The composites with 0-60 phr of A200 were also been fabricated by latex mixing plus extra open-milling methods.Temperature modulated differential scanning calorimetry (TMDSC) was used to investigate glass-transition behavior of composites prepared by both methods, while dynamic rheology tests were carried out to investigate the reinforcement of the compounds prepared by the latex mixing plus extra open-milling methods.TMDSC results show that the content of the glassy layer immobilized in the close vicinity of A200 nanoparticles increases proportionally with silica loading regardless of mixing methods.Comparision between TMDSC and rheology results indicates that there exists an outer absorption layer besides the glassy layer in compounds.The glassy layer corresponds to the XBSR fraction surrounding nanosilica that does not undergo glass transtion.On the other hand,the outer layer is able to undergo glass transition together with the bulky rubber phase but it behaves rigidly at high frequencies.These two layers contribute both to the reinforcement effect.Assuming equivalent A200 spheres of 6.8 nm in radius,equivalent thicknesses of the glassy and outer layers are estimated as 1.0 nm and 1.6 nm,respectively.关键词：Carboxylated styrene-butadiene rubber (XSBR);Nanosilica;Glassy layer;Temperature modulated differential scanning calorimetry (TMDSC);Rheoloy
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发布时间：2021-03-19 - 摘要：Aromatic heterocyclic phosphate aluminum (AHP-AlOH),three types of alkali metal salt of lauric acid (AMSLA) and their composites were mixed into iPP through melt blending method,respectively.The resultant iPP samples were characterized by polarizing optical microscopy (POM),differential scanning calorimeter (DSC) and their corresponding properties were also tested.The results showed that the crystallization peak temperature and nucleation efficiency of the iPP samples,prepared with mixed AMSLA and APH-AlOH,were higher than those of the other iPP samples.With taddition of AMSLA alone,the nucleation effect is not significant.The mean size of spherulites maintained the same as that of the raw iPP which is 161 μm.The crystallization peak temperature increases by less than 6.5℃,and the nucleation efficiency is merely 20%.APH-AlOH shows medium nucleation ability on iPP.The mean size of spherulites decreases to 16 μm.The crystallization peak temperature increases by 13.7℃ and the nucleation efficiency is 45.4%.However,when the mixture of AMSLA and APH-AlOH is introduced together,the mean size of spherulites decreases to a size below 5 μm.The crystallization peak temperature increases by more than 20℃ and the nucleation efficiency is higher than 60%.The tensile strength,flexural strength,flexural modulus,heat distortion temperature (HDT) and transmittance of these composites increase by 6.4%,17.3%,18.6%,25.2% and 15.1%,respectively,and the haze decreases by 70.3% compared to iPP matrix.Additionally,the type of alkali metal ions of AMSLA has an obvious effect on the nucleation efficiency of the mixture of AMSLA and APH-AlOH.The crystallization peak temperature,mechanical and heat-resisting properties follows the order of Na+ > K + > Li +,while the optical property follows the order of Li+ > Na + > K +.关键词：Nucleating agents;Isotactic polypropylene;Alkali metal salt of lauric acid;Aromatic heterocyclic phosphate salt (AHPS);Synergistic effect
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发布时间：2021-03-19 - 摘要：Ultrahigh molecular weight polyethylene (UHMWPE) fibers were treated by atmospheric air dielectric barrier discharge (DBD) plasma with the aim of surface wetting and adhesion properties improvement.The influences of DBD plasma treatment time and voltage on the properties of fibers such as tensile strength,contact angle,surface morphology,surface chemical composition and surface adhesion force were studied.SEM images show that many micro-cracks which are perpendicular to the fiber axis appear on the surface of the fibers,resulting in a rougher surface than the control fiber.XPS analysis declared significant decrease in carbon content and notable increase in oxygen and nitrogen contents on the surface of air DBD plasma treated UHMWPE fibers.Moreover,the increase ratio of oxygen content is much higher than that of nitrogen content on the surfaces of UHMWPE surfaces.Meanwhile,XPS deconvolution analyses show that the composition of C-O/C-N groups increases significantly and new groups of C=O and O-C=O appear on UHMWPE surfaces after DBD plasma treatment.Meanwhile,the contact angle measurement and interfacial shear strength (IFSS) with epoxy resin test show that the surface wettability of UHMWPE fiber as well as the surface adhesion force increased firstly but then decreased with the increase of DBD plasma treatment time and voltage.In addition,after air DBD plasma treatment,the tensile strength of the UHMWPE fiber decreased slightly.The results show that the tensile strength of the UHMWPE fiber decreased less than 5.2% when the treatment voltage is lower than 200 V and the treatment time is shorter than 100 s.关键词：Ultra-high molecular weight polyethylene fiber;Dielectric barrier discharge;Surface properties;Adhesion force
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发布时间：2021-03-19 - 摘要：Scanning electron microscope (SEM) was used to study the microcellular structure of the damping material.Universal material testing machine (UMTM),dynamic mechanical thermal analysis (DMA) and rotational rheometer were used to measure the mechanical properties and damping properties under different conditions.For the three different damping materials,it was observed that the value of the critical compression strain where the damping material changed to non-linear deformation regime was connected with the ratio of microcellular area versus the bulk area of cutting surface.It was inferred that the slow growth of stress for damping materials under small compression strain was contributed from the deformation of microcellular.As the compression strain was further increased,the deformation of microcellular reached its limitation,and accordingly,the rapid growth of the stress was mainly caused by the deformation of the bulk polyurethane.It was observed that the hysteresis energy of damping materials increased with the maximum compression strain was increased,and the damping material with better damping properties had bigger hysteresis energy.It was found that the loss angle of damping materials increased slightly with compression frequency,which affects the damping properties and the generated heart of the damping materials with different compression frequency.It was also observed that the loss angle of damping materials changed with temperature,and the loss angle would change slightly under wider range of temperature for the damping material with better low temperature resistance and high temperature resistance.It was also found that the damping properties of samples decreased when a bigger load was applied.关键词：Polyurethane;Damping material;Polymer;Automobile
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发布时间：2021-03-19 - 摘要：We mainly investigate the interaction of a lipoparticle with a giant vesicle in solvent by using the self-consistent field theory method.A certain distance of the lipoparticle and the giant vesicle is set as the initial state.As the lipoparticle is close to the giant vesicle,the lipoparticle will interact with the giant vesicle.With decreasing the distance between the lipoparticle and giant vesicle,the interaction with each other increases gradually.We discuss the influence of hydrophilic and radius of the lipoparticle on the membrane structure of the giant vesicle,respectively.When the hydrophilic of lipoparticle is changed,a lot of interesting structural transformation can be obtained during the transmembrane process.It is mainly stalk phase and hemifusion diaphgram (HD phase) when the hydrophilic fraction (f) is 0.35; and it is inverted micellar intermediates (IMI phase) when f=0.3.When f=0.25,it can form hydrophilic aggregates of rod,which is called rod HII phase.It occurs multiple scattered IMI phase when f=0.2.However,there is a little effect on the membrane structure of giant vesicle when the radius of inclusion particle of lipoparticle is changed.In addition,we calculate the free energy of the system quantitatively.The system free energy decreases with the decrease of the distance between the lipoparticle and the giant vesicle.It is shown that the interaction between the lipoparticle and giant vesicle is a spontaneous process with the decrease of the distance.It is important to overcome an energy barrier for the new morphology in the interaction.The energy barrier will increase if the hydrophilic fraction of the lipoparticle increases.When the phospholipid head volume fraction increases,it reduces the spontaneous curvature of membrane.The system free energy also increases with the increase of the radius of the inclusion particle.关键词：Lipoparticle;Giant vesicle;Self-consistent field;Self-assembly
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发布时间：2021-03-19
Research Article
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