最新刊期
卷 ， 期 9 ， 2011
- 摘要：The investigations on macromolecular interactions at the single-molecule level using atomic force microscopy (AFM) imaging and AFM-based single-molecule force spectroscopy (SMFS),with an emphasis on the combination of these two methods,have been discussed on the base of the author's recent work in related fields.First,AFM imaging (including static air phase and in situ liquid phase AFM imaging) is used to detect the effect of protein-binding on the topology of double stranded DNA (dsDNA) based on the characteristic (spaghetti-like) AFM image of dsDNA.Then,SMFS study on the nature of force-induced conformation transition of dsDNA is demonstrated.The force-fingerprint of dsDNA can then be used to study protein-DNA interactions revealing the effects of protein-binding on the dynamic conformation of dsDNA.In addition,the application of AFM-based SMFS in the investigation of RNA-protein coat interactions in an intact plant virus,tobacco mosaic virus (TMV),has been demonstrated.To realize this,a TMV particle is immobilized perpendicularly on a gold-coated substrate.The genetic RNA can then be pulled step-by-step out of the TMV particle through its 5' opening.This study extends the force spectroscopy technique to the investigation of nucleic acid-protein interactions in more complicated biological systems (i.e.,in the virus particle).Finally,the attempt in the quantitative study of polymer interactions in a polyethylene oxide (PEO) single crystal is successfully accomplished by pulling a single PEO chain via its thiol-labelled end out of its single crystal by a good in situ combination of AFM imaging and SMFS.The generality of the established method in the investigation of crystallization of other polymers is discussed.This quantitative information on inter-and intramolecular interactions of macromolecules is useful in revealing the mechanism of many important biological processes (such as DNA replication) as well as in the design of high-performance polymer materials.关键词：Atomic force microscopy;Single-molecule force spectroscopy;Nucleic acid-protein interaction;Polymer single crystal
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发布时间：2021-03-19 - 摘要：The layer-by-layer (LbL) assembly has been demonstrated to be a convenient and versatile method to fabricate composite film materials with precise control of film composition and structure.Polymeric complexes represent a large variety of supramolecular assemblies hold together by multiple weak interactions,which include polyelectrolyte-polyelectrolyte complexes,polyelectrolyte-surfactant complexes,non-charged polymer-polymer complexes,polymeric-inorganic hybrid complexes and so forth.We demonstrate herein that the LbL assembly is unique to fabricate functional films by using polymeric complexes as building blocks:(1) It enables rapid fabrication of micrometer-thick films because of the large dimension of the polymeric complexes.(2) It facilitates the flexible control of film structures because the structure of polymeric complexes can be easily tailored in solution or in LbL assembled films.(3) The LbL assembly of polymeric complexes can build up novel functional films which are difficult or impossible to fabricate by LbL assembly of uncomplexed polymers.关键词：Polymeric composite films;Functional films;Layer-by-layer assembly;Polymeric complexes
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发布时间：2021-03-19 - 摘要：Intermacromolecular complexation occurring among the macromolecules with complementary structure through the secondary binding forces,e.g.Coulomb forces,hydrogen bonding,van der Waals forces,charge transfer interactions etc.,is an effective supermolecular method for preparation and property enhancing of polymer materials.This paper summarizes our research work on intermolecular complexation in recent years,e.g.,realizing the thermal processing of PVA and developing a series of novel PVA products with high performance,preparing novel halogen free flame retardant,controlling the crystalline structure of POM and effectively improving its notched impact properties and friction and wear properties,etc.关键词：Intermolecular complexation;High performance polymer;Supermolecular method
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发布时间：2021-03-19 - 摘要：Polymer-nanocrystals composite materials have attracted much attention for combining the advantage of both the organic and inorganic materials,the polymer provides an inert environment for the formation and growth of the nanocrystals,and nanocrystals in return enhance the performance of the polymer.Such as the TiO2-triethoxysilanecapped polythiourethane (TCPTU) composite optical films,the films not only retained the origin properties but also achieved a high refractive index.Besides,there are lots of different polymer-nanocrystals composite materials such as PDMAA/ZnS,PbS/PTU nanocomposites.The organic-inorganic materials could also be used to prepare the high performance photoluminescence materials besides the high refractive optical films.CdTe nanocrystals covered with negative charge could be transferred from water to organic solvent through the electrostatic force.At last,through radical polymerization,the bulk materials with a uniform distribution of the nanocrystals could be obtained.In turn,polymer could be used as a friend media to control the growth of the CdTe nanocrystals and realize the precise control and the performance optimization.The luminescent color under the UV light could be controlled by changing the size of the nanocrystals.What's more,as a kind of functional polymer,PPV precursor could be combined with CdTe nanocrystals to prepare pure white-light composite materials and also high performance photovoltaic devices.关键词：Polymer;Nanocrystals;Composite materials;High refractive index;Functional materials
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发布时间：2021-03-19 - 摘要：This feature article is to summarize the methods of preparing surface molecular imprinted films utilizing unconventional layer-by-layer (LbL) assembly.Template molecules first preassembled with polyelectrolyte in solution to form supramolecular complex.Thus preassembled complex was used sequentially as a building block to construct LbL thin film with other photoreactive building block such as diazoresin at solid/liquid interface.Through photo cross-linking in between layers of the multilayer film following with template washing,the surface molecular imprinted LbL (SMILbL) film was generated.Diversified interactions have been introduced to fabricate the SMILbL film,and the selectivity of the SMILbL film could be effectively enhanced by the introduction of multivalent interaction.For practical application purposes,cation selective stamps and charge selective membranes have been demonstrated by combination of SMILbL film with corresponding microcontact printing and membrane separation technique,providing a new avenue for surface molecular imprinted materials.关键词：Unconventional layer-by-layer assembly;Molecular imprinting
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发布时间：2021-03-19
Feature Articles
- 摘要：Self-assembly is ubiquitous in nature.Biological systems utilize nonocovalent forces to control the self-assembly process precisely,resulting in the formation of complicated structures with multiple functions.Inspired by the structure of biological macromolecules,chemists are engaged in developing highly-ordered artificial supramolecular assemblies such as supramolecular polymers,which exhibit great significance in the formation of various supramolecular architectures,and more importantly,the potential applications of dynamic supramolecular materials.In recent years more and more attentions have been paid to crown ethers,one of the most commonly used hosts in supramolecular chemistry,which serve as the building blocks to construct functional supramolecular assemblies due to their facilitated syntheses,convenient structure modification and unique complexation properties with a variety of guest molecules.This review focuses on supramolecular polymers based on crown ether derivatives.关键词：Crown ether;Supramolecular chemistry;Supramolecular polymer;Self-assembly
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发布时间：2021-03-19 - 摘要：Since its discovery,living olefin polymerization has attracted much attention due to its ability to produce polymers with pre-determined molecular weight and narrow molecular weight distribution,various block copolymers and end-functionalized polymers.Metal-catalyzed olefin polymerization was considered to be highly active and superior in stereochemistry control.Therefore,their living polymerization has been paid much attention in the past decade.Complexes with early-transition metal centers such as Ti and Zr have been investigated comprehensively in catalytic olefin polymerization,and many of them are found to exhibit living behavior.In comparison,late transition metal catalysts are rare with regard to catalytic living olefin polymerization,but they develop rapidly and act differently to their early transition analogues.In this review,advances in late transition metal catalysts for living olefin polymerization and related factors affecting the living behavior are summarized.A comparison is made between late-transition living polymerization catalysts and those of the early-transition metals.关键词：Late transition metals;Olefin polymerization;Living polymerization;Catalysts
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发布时间：2021-03-19 - 摘要：Amphiphilic block copolymers in selective solutions can self-assemble into various morphologies, such as spherical, rodlike and disklike micelles, bilayer membranes, vesicles and nanotubes. These aggregated nano-structures are of great potential in drug delivery, microelectronics and advanced material applications. Therefore, it is very important to study the phase behaviors of block copolymers and understand the formation mechanism of complex aggregated nano-structures. Due to the complexity of these aggregated nano-structures, computer simulations can be used as a powerful tool to study the phase behaviors of block copolymers. In this review, we mainly cover recent developments in the field of mesoscopic computer simulations of structure design for block copolymers. Specifically, dissipative particle dynamics simulations, self-consistent field theory dynamic density functional theory and Monte Carlo simulations will be the main themes in this review.关键词：Block copolymer;Nano-structure;Mesoscopic simulation
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发布时间：2021-03-19 - 摘要：In the past few decades,conjugated polymers,which are composed of repeating structural units and these subunits are typically connected by covalent chemical bonds,have attracted broad interest due to their unique optical,electrical and electrochemical properties.Due to the complexity of the conjugated polymers structure,such as chain segment,conformation and aggregation,it's difficult to synthesize defect-free polymers even use fine synthesis conditions.The low-energy emission from defects was enhanced in the film state compared to that in the corresponding solution,because the excited energy can transfer to defects effectively.The research of the structural defects in the conjugated polymers included the forming mechanism and control of defects,the analysis of defects density,the molecular structure and electronic structure of defects,etc.It's important to develop high quality materials.In this paper,we describe the progress of studies on defects in conjugated polymers.关键词：Conjugated polymer;Defect;Poly(p-phenylene vinylene) (PPV);Polyfluorene (PF)
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发布时间：2021-03-19 - 摘要：Jamming occurs when a system develops a yield stress behaves as a solid in a disordered state,and it governs the transition behavior of foams,emulsions,colloidal suspensions,pastes,granular media and molecular glasses.For polymer glasses,when the interchain proximity was enlarged,the weak interaction between polymer chains was decreased,and these loosely packed chains can flow solely by applying pressure at temperature 132 degrees below their calorimetric glass transition temperature,Tg,which means Tg decreased to a great extent in this progress.This phenomenon is connected to the concept jamming,which suggests the generality of an idea that one can take polymer glasses through solid-to-liquid transition by thermalization,through temperature,or by a load.It is expected within the jamming picture that we could process polymers at lower temperature or even at room temperature.关键词：Unjamming transition;Cold flow;Polymer processing;Glass transition
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发布时间：2021-03-19 - 摘要：Polymer vesicles or hollow spheres as macromolecular self-assemblies are of great importance in theoretical studies as well as broad applications,especially in medicine fields.In this article,discussions on different routes of preparation of polymer vesicles or hollow spheres were presented.The traditional preparation methods for the assemblies include self-assembly of block copolymers,shell crosslinking and core removal of copolymer micelles and synthesis on the templates.The methods via non-covalently connected micelles (NCCM),as well as the one-step synthesis from monomers to polymer vesicles were reviewed in detail.These methods have overcome the laborious multistep processes including using a preorganized structure and subsequent removal of the core or templates et al.Recent progresses in functional block copolymer vesicles,such as the micelle-vesicle transition,breathing vesicles,bursting of sensitive polymersomes and surface modification of polymeric vesicles have been highlighted.关键词：Polymer vesicle;Hollow sphere;Preparation method;Functionalization
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发布时间：2021-03-19 - 摘要：Selenium (Se),known as an essential trace elements,is closely related to human health and diseases.This essential trace element exists in at least 25 selenoproteins in the form of selenocysteine residue,which performs a variety of biological functions.Among these selenoproteins,glutathione peroxidase (GPx) is a well-known antioxidase,since it catalyzes the reduction of harmful peroxide by glutathione and protects cells against oxidative damage.Herein,some strategies and methods are presented to construct GPx mimics based on protein scaffolds.Through these studies,we expect to gain better understanding of the biological properties of selenoprotein,and even develop more effective approaches to create new selenoprotein mimics.关键词：Selenium (Se);Selenocysteine;Glutathione peroxidase (GPx)
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发布时间：2021-03-19
Reviews
- 摘要：A novel cellulose hydrogel was prepared by regenerating cellulose from its ionic liquid (IL) 1-allyl-3-methylimidazolium chloride (AMIMCl) solution.The results from elemental analysis and FTIR spectroscopy indicate that the cellulose hydrogel was composed of only natural cellulose and water.Therefore,the hydrogel is non-toxic and can be a promising material in bioengineering.UV-Vis spectra demonstrate that the cellulose hydrogel has a good transparency,especially in the larger wavelength region.For instance,a 2 mm-thick hydrogel can reach 80% transmittance at 650 nm.The results of compression test show that the cellulose hydrogel has an acceptable mechanical property.All the cellulose gels (the cellulose content differs from 1% to 3%) can bear a strain more than 50% upon compression without failure,which allows normal handle in applications.Numerous nano-pores with size of 20~60 nm can be observed from the SEM images of the cellulose hydrogel,indicating that the hydrogel may be utilized in separating nano-sized objects.In this study,we find that cellulose hydrogels reconstituted from its IL solution can be used as the diffusion matrix in gel electrophoresis (GE),and our preliminary results show that dyes and even proteins can be successfully separated.As a green material,the cellulose gel is expected to overcome the disadvantages of the polyacrylamide gel,which is traditionally used in GE.The mechanism of the formation of cellulose hydrogel from its IL solution was also discussed.It is observed that several kinds of solvents can prepare cellulose hydrogel from its IL solution.The experiment results suggest that the properties of a certain solvent determine whether cellulose gel can be prepared in the solvent bath.If the solvent is miscible with the IL,and the molecule of the solvent has one or more active H atom,then the solvent may form a H-bonding network with the IL solution,which is helpful for the formation of the cellulose gel.关键词：Cellulose;Hydrogel;Gel electrophoresis;Formation mechanism
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发布时间：2021-03-19 - 摘要：A series of manganese-based ferrocenyl coordination polymer microspheres were prepared by solvothermal reactions,the influence of reaction time and reagent concentration on the morphology and diameters of microspheres was investigated systematically,and the morphology,diameters and crystal structure of manganese-based ferrocenyl coordination polymer microspheres were characterized by scanning electron microscopy (SEM),transmission electron microscopy (TEM),powder X-ray diffraction (PXRD),energy dispersive X-ray spectrometry (EDX) and Fourier-transform infrared spectroscopy (FT-IR).By adjusting the reaction time from 8 h,12 h to 24 h,the diameters of microspheres increased from 4 m to 9.4 m; on the contrary,the increase of reagent concentration decreased the size of particles from 11.4 m to 9.4 m at the tested range,and,at the same time,spheres were transformed from smooth spherical structures into core-shell structures.PXRD showed that manganese-based ferrocenyl coordination polymers crystallized into sandwich layered crystal structure with the possible formula of Mn4(OH)4(OOCC5H4FeC5H4COO)2. Within the framework,two kinds of different manganese atoms in a distorted octahedral geometry were incorporated into the layers and the ferocenedicarboxylato group existed as a synperiplanar conformation and tridentate-bridging mode connecting three manganese atoms.Manganese atoms were connected with oxygen atoms to form a two-dimensional inner layer with the ferrocenyl groups arranged along two sides of the inner layer,thus forming the sandwich-like coordination polymers.EDX indicated the microspheres contained Mn,Fe,C and O,and C O stretching frequency shifting from 1687 cm-1 for the precursor to 1581.7 cm-1 for the product from FT-IR spectra confirmed the formation of coordination polymer.TGA showed the coordination polymer microspheres had good thermal stability up to at least 319℃.关键词：Coordination polymer;Microsphere;Ferrocene;Manganese
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发布时间：2021-03-19 - 摘要：The thickening process of lamellar crystals from two folded-chain (2-FC) lamellae through one folded-chain (1-FC) lamellae finally to extended chain (EC) ones in bulk samples of a poly(ethylene oxide) (PEO) with a molecular weight of 5000 was studied.The samples with 2-FC crystals were prepared by quenching them from their melt to liquid nitrogen.During reheating them or treating them at selected annealing temperatures,we tracked the lamella-thickening process using small-angle X-ray scattering (SAXS).After analyzing the SAXS data and the corresponding one-dimensional correlation functions,we found that below 52℃ 2-FC crystals primarily thickened into 1-FC crystals; but above 52℃ 2-FC crystals mainly thickened into EC crystals.In the temperature region between 58℃ and melting point of the EC crystals,the newly formed 1-FC crystals will further thicken into EC crystals.Our observations using polarized light microscopy (PLM) and scanning electron microscopy (SEM) show no changes of crystalline superstructures,such as spherulites,formed by these crystals.Therefore,we can conclude that the thickening process,we observed in this crystalline PEO samples,do not cause any destruction of large crystalline superstructures,so it is a process only containing melting of thinner lamella crystals and then recrystallization of the molecules into thicker lamella crystals.More importantly,this process is strictly restricted within some local regions of large crystalline superstructures.关键词：Poly(ethylene oxide);Lamellar crystals;Thickening;SAXS
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发布时间：2021-03-19 - 摘要：A series of block copolymers of styrene and sodium 2-vinylterephthalate (sodium 5-vinylisophthalate) was synthesized via atom transfer radical polymerization (ATRP).Their structures were confirmed by 1H-NMR,gel permeation chromatography (GPC),and thermogravimetric analysis (TGA).These copolymers had good thermal stability and were used as nucleating agents for PET.Differential scanning calorimetric (DSC) experiments were carried out to study the relationship between polymer structures and the effect on improving the crystallization of PET.Compared with pure PET,PET/copolymer blends showed higher crystallization temperatures and higher crystalline enthalpies.Ubbelohode viscometer was used to measure the intrinsic viscosities of PET and PET/copolymer blends.One-dimensional wide-angle X-ray diffraction (1D WAXD) experiments were carried out to determine the crystalline structure of samples.The results indicated that all these block copolymers were effective PET nucleating agents.They were able to not only improve the crystallization process of PET,but also retain the molecular weights of the samples.关键词：PET;Nucleating agents;Block copolymers
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发布时间：2021-03-19 - 摘要：In order to physically elucidates the anomalous intrinsic viscosity of dendrimers,first,the radial segmental density profile of dendrimers is calculated by the self-consistent mean field method.Secondly,based on the two-zone model proposed,the intrinsic viscosity as a function of generation of dendrimers with the following parameters,including the number of generations,the functionality of the core,the length of spacer,the effective coefficient of correlation and the excluded volume is systematically investigated.Thirdly,the origin of dendrimers'anomalous intrinsic viscosity is elucidated in the microscopic scale,namely the competition of the number fraction between the two kinds of monomers without the capability of dragging solvent,which is caused by the increase of volume of the core and the back-folding ability caused by entropy effect.Finally,it is physically elucidated that the nature of the intrinsic viscosity is the reflection of the ability per monomer of dendrimer to averagely drag solvent molecules alone rather than the reflection of the degree of polymerization.This research will be benefit for the optimum design of dendrimer materials in the corresponding application areas.关键词：Dendrimer;Intrinsic viscosity;Two-zone model
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发布时间：2021-03-19 - 摘要：The influence of phase transition on the filler network in the isotactic polypropylene/carbon black(emPP/CB)composite was studied.The combination of dynamic rheological and electrical measurements was used to monitor the evolution of the conductive resistivity and storage modulus of the composite during melt annealing and in situ crystallization and melting.In order to obtain a composite with a good filler dispersion state and with a strong tendency of filler aggregation,the mild blending method was used to fabricate the composite.An emPP/CB composite containing 6 wt% CB was used.The results suggest that the CB particles can aggregate and form a filler network in the composite during melt annealing,while the formed filler network could be affected by the phase transition (crystallization and melting) of the polymer matrix.In the crystallization process,the resistivity of the composite increases slightly,indicating that the growing lamellae can maneuver the filler particles and break some weak linkages in the filler network.In the melting process,the resistivity of the composite increases significantly,revealing the expansion of the polymer matrix leads to the significant breakdown of the filler network.After in situ crystallization and melting,the filler network which can be detected by the dynamic rheological experiment disappears,demonstrating that the phase transition breaks the filler network.The different developments of the storage modulus before and after phase transition show that the phase transition process cannot destroy all the aggregation structure which has formed in the previous melt annealing process.The filler network can be reconstructed quickly after in situ crystallization and melting.关键词：Composite;Filler network;Aggregation;Dynamic rheology;Phase transition
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发布时间：2021-03-19 - 摘要：The phosphaphenanthrene-containing 1-pentyne monomer (M-34) was synthesized through the successive esterification of 2-(6-oxide-6H-dibenz1,2oxaphos-phorin-6-yl)-dihydroxyphenylene (ODOPB) with 4-(4-pentynoxy)benzoyl and 4-butyloxybenzoyl,respectively.Due to the introduction of 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) group,the catalytic ability of Rh-based catalysts ([Rh(nbd)Cl]2 and Rh(nbd)B(C6H5)4) is decreased and the yields of polymer are relatively low.The polymerization of model monomer (M-0) in the absence of phosphaphenanthrene side-group was,however,carried out in high yield at the same condition.The microstructure of the poly(1-pentyne) derivants was characterized by means of 1H-NMR.The experimental results indicate that the main-chains of poly(1-pentyne) derivants with high trans-content configuration are produced due to the strong - stacking and polar interactions between phosphaphenanthrene-containing pendent groups.Thus,the interaction between adjacent pendent groups is further strengthened.The molecular weights and distribution of P-34 and its model polymer P-0 were measured by GPC; Their thermal properties were evaluated by TGA and DSC.Comparing with P-0 in the absence of phosphaphenanthrene side-group,TGA analysis reveals the excellent thermal stability of P-34,losing 1% of weights during heating to 270℃ and retaining 50% of weights after pyrolyzis at 550℃.And the char yield of P-34 is over 50 wt% at 550℃.The DSC results indicate that Tg of P-34 is lower than that of P-0 because DOPO increases the volume of side-groups in P-34.关键词：Poly(1-pentyne);Rh-based catalyst;Phosphaphenanthrene;Thermal properties
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发布时间：2021-03-19 - 摘要：A water soluble cationic fluorescent probe (TPEDPyMe) was designed and synthesized by attaching two pyridinium moieties onto the tetraphenylethene(TPE) core.The molecular structure of TPEDPyMe was characterized by multiple spectroscopic techniques,and its fluorescence property was examined.As its maternal compound,TPEDPyMe exhibited typical aggregation-induced emission (AIE) behavior,and the emission peaked at around 630 nm in aqueous solution.TPEDPyMe was used as a fluorescent probe to detect ctDNA in tris-HCl buffer solution at a pH value of 7.2. It was found that the fluorescence intensity of the TPEDPyMe in the buffer solution was boosted up to 20 folds when the concentration of ctDNA increased from 0 g/mL to 500 g/mL.Meanwhile,the emission peaks blue-shifted from 627 nm to 576 nm.In the concentration region from 0 g/mL to 50 g/mL,the change in fluorescence intensity was linearly proportional to the concentration of ctDNA.In this region,the Stern-Volmer constant or KSV was calculated to be 1.4 102,showing a desirable sensitivity of TPEDPyMe to ctDNA.Moreover,when the concentration of ctDNA increased from 0 g/mL to 500 g/mL,the emission peak shifted from 633 nm to 578 nm.This phenomenon implies that the TPEDPyMe can be used as a dual-responsive fluorescent label for probing ctDNA,which is of great significance in biosensor technologies.In summary,the present results indicate that TPEDPyMe is a promising fluorescent probe for the detection of DNA species and more detailed investigation is going on in the laboratory.关键词：DNA detection;Aggregation-induced emission;Tetraphenylethene;Fluorescent probe
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发布时间：2021-03-19 - 摘要：A novel fluorescent cationic polymer,genipin cross-linked branched oligoethylenimine(1800 Da,OEI1800),GP,was successfully synthesized in 70% ethanol solution and evaluated as a non-viral gene carrier.The copolymers were characterized by nuclear magnetic resonance spectroscopy (1H-NMR) and gel permeation chromatography (GPC).The complexes of copolymers/DNA based on GP were measured by dynamic light scattering and Zeta potential instrument.The results showed that the synthesized copolymers could efficiently condense DNA into nanosized particles (120~150 nm) with positive surface charges (+20~25 mV).The DNA-binding ability of the copolymers was further examined by gel retardation assy.When the mass ratio of polymer and DNA was 0.25,the plasmids were fully retarded in 1% agarose gel by gel retardation electrophoresis.Moreover,the in vitro cytotoxicity and transfection efficiency of the GP copolymers were respectively tested by the MTT and luciferase assay,using OEI1800 and PEI25k as the control in the HEK293 cells lines.The cell toxicity and gene transfection evaluations showed that the copolymers exhibited lower cytotoxicity and higher gene transfection efficiency than PEI25k in the HEK293 cell lines.Finally,the carriers could be used as the fluorescent labeling materials.Therefore,the copolymers may have potential biomedical application as non-viral gene carriers.关键词：Genipin;Oligoethylenimine;Transfection;Gene carrier;Fluorescence
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发布时间：2021-03-19 -
LAYER-BY-LAYER ASSEMBLY OF A HALOGEN-BONDED POLYMER MULTILAYER FILM AND IMPROVEMENT OF ITS STABILITY
摘要：Poly(2-(4-iodo-2,3,5,6-tetrafluorophenoxy)ethyl methacrylate) (PIPEMA) and poly(3-(3-pyridyl)propyl methacrylate) (PPyPMA) were designed and synthesized with iodotetrafluorophenoxy group as halogen-bonding donor and pyridyl group as halogen-bonding acceptor.After layer-by-layer assembly and verification with UV-Vis absorption spectroscopy,a halogen-bonded PIPEMA/PPyPMA multilayer film was successfully assembled in acetone and methyl ethyl ketone (MEK),while PIPEMA and PPyPMA were not assembled into a multilayer film in tetrahydrofuran (THF) or chloroform.The PIPEMA/PPyPMA multilayer film was further characterized with quartz crystal microbalance,atomic force microscope and surface profiler.The PIPEMA/PPyPMA multilayer film assembled in MEK is stable in water with pH values between 3 and 13 because the two polymers can not be dissolved in water.In contrast,the polymer film was desorbed in THF,chloroform and pyridine with maximum film loss greater than 97%.In order to improve the stability of a multilayer film in organic solvents,two approaches were applied.(1) A PIPEMA/PPyPMA multilayer film was cross-linked with 1,3-dibromopropane.As for the cross-linked film,the maximum film loss in THF is less than 6%.(2) A copolymer bearing both hydrogen-bonding donor and halogen-bonding donor was designed and synthesized.As for a multilayer film of the copolymer and PPyPMA,the film loss in THF decreased to 46%.关键词：Halogen-bonding;Layer-by-layer assembly;Organic solvents;Desorption;Cross-link;Stability- 32
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发布时间：2021-03-19 - 摘要：Natural polymers have attracted much attention because of the rising demand for materials with features of renewability,non toxicity,biocompatibility and biodegradability.Cellulose and gelatin were the two abundant resources from plant and animal,and it was significant that new biomaterials were prepared by using these two natural polymers.In this work,a series of cellulose/gelatin (C/G) films were prepared in NaOH/urea aqueous solution via a simple,low cost,green pathway.To overcome the disadvantages (brittleness,poor water resistance) of the protein material,gelatin was combined with the regenerated cellulose(RC) film to construct cellulose/gelatin composite materials.The strong interaction between the two macromolecules was confirmed to exist in the composite materials,leading to the improvement of the water resistance of gelatin.Cross-linking with glutaraldehyde further improved the mechanical properties of the composite materials.Their structure and properties were characterized by element analysis,FTIR,ultraviolet-visible (UV-Vis), 13C solid-NMR,scanning electron microscopy (SEM),tensile testing and swelling test.The results revealed that good compatibility existed between cellulose and gelatin in the composite films.The mechanical properties and the water resistance of the crosslinked films were significantly improved.Furthmore,by proliferation of COS7 cells on the surface of the C/G films,they exhibited good biocompatibility,supporting cell adhesion and growth.关键词：Cellulose;Gelatin;Non-covalent bond;Biocompatibility
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发布时间：2021-03-19
Research Article
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