研究生文献汇报.ppt

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,单击此处编辑母版标题样式,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,应用表面与胶体化学教育部重点实验室,Key Laboratory of Applied Chemistry&Colloid Chemistry,MOE,Coreshell polymers:a review,RSC Adv.,2013,3,15543-15565,Reporter:,Rui,Niu,Jianwu,Guo,Xiaobo,Teng,2013.11.20,Content,1.,Introduction,2.,Classifications,3.,Preparation,of core-shell,4.,Development of latex particle,morphology of CPS,5.,Characterizations,6.,Recent study on core-shell polymers,7.,Applications,8.,conclusion,1.Introduction,In1961,Hughes,and,Brown,investigated the,physical properties,of coreshell,polymer(CSP),and their interesting,morphology,.This class,of material has attracted,much attention,because of the,combination of,superior properties,not possessed by the,individual components.The systems might combine the,characteristics and properties of both shell and core,where,the,surface properties,of the shell are,translated to the core,imparting new functionality to the CSP.,Macromolecules,2003,36,(6),19881993.,CSPs,are structured composite particles consisting of at least,two different components,one in principle forms the core and another forms the shell of the particles.,2.Classification,Core shell polymers,(,CSPs,),State,Hydrogels,NIPAM,Non-NIPAM,Conventionalmonomer,Acrylamide,derivatives,Size,Nano,Micro,Non-,Hydrogels,Non-aqueous,Organic-inorganic,Single,2.1 Coreshell polymer,hydrogels,a,hydrogel,shell surrounding a non-,hydrogel,core,Hydrogel,in both core and shell components,Coreshell polymer,hydrogels,Property,:,CSP,hydrogels,have been produced either to,modify,the,stability,and physical properties of the polymers or to impart,stimuli-responsive properties,to responsive particles.,Application,:,CSP,hydrogels,made of,smart materials,have,widespread applications,especially in,biomedical areas,as their response to surrounding,environmental changes,such as temperature and,pH,etc,.,Adv.Drug Delivery Rev.,1996,18(2),219267.Macromolecules,1998,31(25),89128917.,2.1.1 NIPAM based CSP,hydrogels,32,switchable,or,smart,materials,poly(N-,isopropylacrylamide,PNIPAM)has been extensively used as a main component in CSP,hydrogels,due to its,thermoresponsive,properties,.,Macromolecules,1998,31(25),89128917,Langmuir,2004,20(11),43304335,J.Colloid Interface Sci.,2012,376(1),97106.,2.1.2 Non-NIPAM CSP,hydrogel,non-NIPAM,CSPs,(conventional monomer),hydrophilic,AAm,hydrophilic,AAc,hydrophobic MMA,hydrophobic St.,produce responsive,CSPs,non-NIPAM,CSPs,(,acrylamide,derivatives),NIPMAM,NNPAM,N-,ethylacrylamide,N-,vinylisobutylacrylamide,used,to polymerize temperature-sensitive,microgels,2.2 Non-,hydrogel,coreshell polymer,Non,Hydrogels,Non-aqueous,Organic-inorganic,Single,Core:,solid polymer particle or rubber,Shell:,hard polymer,Used:,paints,coating applications,pigments,binder,Used,：,nanotechnology and biomedical applications,such as a signal-molecular template,live-cell imaging,drug carrier and drug release.,Def:,non-cross linked,CSPs,consisting of,amphiphilic,block or graft polymers in which hydrophobic and hydrophilic segments are covalently connected with the,dendritic,or,hyperbranched,core-shell.,在下面介绍,J.Am.Chem.Soc.,2010,132(35),1221812221,synthesis of new functional materials for,light-emitting,devices,solar cells,photodetectors,biomedical,and,sensor applications.,Core,surfactant,poly(ethylene oxide),poly(vinyl benzyl chloride),poly(vinyl,pyrrolidone,),polymer,different copolymers,poly(styrene acrylic acid),Shell,metals,metal oxides,metal,chalcogenides,silica,Adv.Mater.,2009,21(5),509534.,J.Mater.Chem.,2012,22(22),1137011378.,Used,Inorganicorganic,CSPs,butadiene,styrene,3.Preparation of coreshell polymers,CSPs,are typically prepared by a series of,consecutive,emulsion,dispersion,or,precipitation polymerization,sequences with different monomer type.,CSP particles,multi-step,One-stage reaction:,a facile method to prepare polymer particles with coreshell morphology.,seed particles as a core material,second or third stage monomer is polymerized in the seed latex particles,Disadvantage:,expensive,timeconsuming,Chim,.,Acta,2003,496(12),5363.,Macromolecules,2009,42(13),45114519.,consecutive emulsion,Dispersion polymerization,：,a class of,larger particles,and,irregular shape of polymer particles,were produced in precipitation polymerization.polymer particles in the range of,115,m,.The formed polymers are,insoluble in continuous phase,.,Based on,ploymerization,classes,emulsion polymerization:,the main process for the preparation of commercial emulsion,which involves,a monomer,that has limited,solubility,in water,.particle diameter is typically within the range of,110,m,.,Macromolecules,2009,42(13),45114519,Part A:,Polym,.Chem.,2001,39(19),34343442,Example,Fig.3 illustrates common methods to prepare,CSPs,described,by Li and Stover,.,emulsion polymerization using reactive surfactants,Two-stage emulsion polymerization was the first general method,step-wise,heterocoagulation,of,smaller cationic,polymer particles onto,larger anionic,heat treatment.,block copolymers can be used to produce coreshell type polymer,nanospheres,via block copolymerization.,3.1 Emulsion polymerization,Emulsion polymerization,synthesized process,is commonly used to produce,water,based,resins,with a variety of,physicochemical,and,colloidal properties,.,Characterized,:,emulsified,monomer droplets,(,1-10 um,in diameter),dispersed,in a continuous aqueous phase with the assistance of an,oil-in-water,surfactant at the very beginning of polymerization.,The emulsion polymerization technique is a commercially and technologically,important reaction system,.This technique continues to grow through its versatile reaction and its ability to tailor the properties of the emulsion,polymer produced,.,Emulsion polymerization,semi-batch process,batch process,The most,significant difference,between batch and semi-batch,emulsion polymerization,Semi-batch process,allows two types of,feed,stream,M(monomer)feed and,E(emulsion)feeds,Batch processes are,of limited,versatility,for producing emulsion,and are mainly use in,academic research,with,simple reaction,formulations.,Advantage of Semi-bath:,(1)Good,temperature,control with extra cooling of polymerization process.,(2)Easy to control,polymerization rate,by keeping process,starved,.,(3)Flexible control of,molecular weight,.,(4)Good polymer,composition,control.,Example one,Lin et al.,prepared,thermoresponsive,CSPs,of P(NIPAM-,co,-,AAc,)or,poly(NIPAM-,co,-SA)copolymer using batch process surfactant-free,emulsion copolymerization(SFEP).,CSPs,Reactant,2h,70,200rpm,Milky white and average diameter of 200 to 500 nm,NIPAM-,co,-,AAc,PH3-4,NIPAM-,co,-SA,PH6-6.2,Example two,Fig.6 A schematic representation of the copolymerization and cross-linking reaction mechanism of AN with NIPAM in sodium,dodecyl,sulfate(SDS)micelles.,Serrano-Medina,prepared,nano/microgels,of poly(P(NIPAM-,co,-PEGMEMA-,co,-2MBA)by,one-stage,surfactant free emulsion polymerization(SFEP),The high sensitivity,of these P(NIPAM-,co,-,AAc,),microgels,to small changes in,pH,and,temperature,suggest that they,could be useful in,drug delivery,applications,Example three,Fig.7 Schematic representation of the formation of the coreshell NPs by semi-batch emulsion polymerization.Reproduced from ref.83 by permission of American Chemical Society.,Ni et al.,synthesized hybrid,nanoparticles,(NPs)with a,polystyrene,core and a hybrid copolymer shell in a,two step process,:emulsion polymerization of,styrene,and subsequent copolymerization of styrene with,-methacryloxypropyltri-methoxysilane,(,MPS,).,3.2 Dispersion polymerization,This technique allows synthesis of,micro particles,in the range of,115microns,.,Most of the ingredients in this process,including,surfactant,initiators,and,monomers,are soluble in continuous,organic phase,and which form polymers,that are insoluble in,continuous phase,.,Example,Li et al.,reported the preparation of narrowly distributed,nanogels,by two-stages dispersion polymerization.,First,the core particles composed of,PNIPAM,were synthesized and then the core particles were used as nuclei in the following stage for subsequent shell addition of poly(4-vinylpyridine)(,P4VP,)(,四乙烯基吡啶,).,3.3 Other techniques to prepare coreshell polymers,Example,one,three-step synthesis approach was used to prepare,thermoresponsive,CSP by Xiao et al.,A single-molecular particle of,hyperbranched,conjugated,polyelectrolyte(HCPE)was synthesized by,Pu,et al.,Example,two,Fig.9 shows a schematic illustration of the synthesis routes of single-molecular,nano,-particles multi-HPBPEA-,g,-PNIPAM,Three-step,synthesis approach,was used to prepare,thermoresponsive,CSP by,Cai,and Liu,to synthesize a novel,single-molecular/,unimolecular,nanoparticle,multi,hyperbranched,poly2-(2-bromopropionyl)oxy),ethyl,acrylate)-,g,-poly,(,Nisopropylacrylamide,(,HPBPEA-g-PNIPAM,),via atom transfer radical,polymerization,(ATRP),.,Mu et al.,prepared a,monodisperse,and multilayer coreshell(MMLCS)via surface cross-linking emulsion polymerization.,Example,three,Fig.10 shows the preparation of multilayer coreshell(MMLCS)emulsion via surface cross-linking emulsion polymerization.The PBA core was synthesized by seed polymerization using the PBA seed at,75 2,for,3.5 h.,GMA:,甲基丙烯酸缩水甘油酯,BA,：丁基丙烯酸酯,Example,four,Thermosensitive,PSt,PNIPAM coreshell particles were synthesized using,photoemulsion,polymerization technique.,This new synthesis strategy may,Produce a,thermosensitive,shell of,PNIPAM networks with more,homogeneous cross-linking density.,Example,five,5 mol%NIPAM,Kim et al.,fabricated,monodisperse,coreshell,microgels,based PNIPAM by capillary,microfluidic,technique.,Used,to develop novel,biomaterials,for,applications in,drug delivery,artificial,muscles,and,cancer therapy,.,Fig.12 Drop formation of pre-,microgel,drops in a capillary,microfluidic,device.,（毛细管装置中微凝胶的液滴状微流动图示意图）,4.Development of latex particle morphology of CSP,Affected by many variables,cross-linking,radical,penetration,diffusion,processing,polarity of,monomers,batch processing,semi-batch processing,4.1 Effect of cross-linking,Durant et al.,have predicted the effect of cross-linked seed latex particles on equilibrium particle morphology of two component particles,which is considered to be,occluded morphology,(OCC),inverse coreshell,(,ICS,)and,coreshell(CS),structures.,Sheu,et al.,prepared core-shell,latices,by seeded emulsion,polymerization of styrene(St),into polystyrene,(,PSt,),latices,with varying amounts of,DVB,cross-linker.,Example,one,Example,two,Fig.14.,PSt,formed a homogeneous shell on uncross-linked,PSt,seed,.The morphology of the shell changed to a snowman structure when,PSt,seed was cross-linked with around 0.2%,of DVB,.At,6%,of,DVB,the shape of the shell changed into a raspberry structure.,4.2 Radical penetration and diffusion,Fig.15 Possible particle morphologies produced from differing radical penetration depth.Reproduced from ref.100 and 104 by permission of Elsevier and Taylor&Francis.,monomers,Latex,particle,penetrates,Ivarsson,et al.and Jo,nsson,studied the influence of the relative difference apparent between,glass transition temperature,T,g,and,reaction temperature,within particle on the ability of,oligomeric,radicals.,One hand,On the other hand,polymer radicals,may be restricted to the periphery of the particles when the radical flux is,high enough,and the monomer feed is,slow enough,for glassy seed polymers,but probably not for low,T,g,seed polymers.,5.Characterizations,TEM and SEM,1,H and,13,C nuclear magnetic resonance spectroscopy,(NMR),Small angle neutron scattering(SANS),Nonradioactive direct energy transfer(NRET),Photon correlation spectroscopy(PCS),Dynamic light scattering(DLS),6.Recent study on coreshell polymers,Coreshell polymers have attracted enormous research interest,both from the point of view of fundamental science and for prospective applications.In addition,the unique properties of CSP attracted scientists to study and developed new,microgel,systems and re-investigated older systems using advanced techniques and methods.,Example one,Yu et al.,prepared,monodisperse,CS,microspheres composed of a,PNIPAM-,co,-PHEMA by,microfluidic,emulsification,freeradical,polymerization and ATRP,.,Example two,Lee et al,.demonstrated that coreshell poly(styrene/,pyrrole,),P(St/Py,)particles were successfully prepared by using Fe,3+,-catalyzed oxidative polymerization with emulsifier-free emulsion polymerization in aqueous medium.The resulting,P(St/Py,)particles showed excellent electrical conductivity(2.21 Scm,-1,)due to the coreshell morphology.,Fig.26(a)shows a schematic for the formation of coreshell,P(St/Py,)particles and(b)the detailed reaction mechanism of,pyrrole,monomers via Fe,3+,-catalyzed oxidative polymerization.,Example three,Zhang et al.,reported a facile method to create a living in situ gelling system for controlled formation of,hydrogels,from a,hyperbranched,polymer(BAP)with disulfide-linked coreshell structures.,Contribution:,they developed an,inverse emulsion technique,to obtain micro or,nanodroplets,of a disulfide-linked coreshell BAP.To produce fine-tunable micro/,nano,drug carriers,having broad implications in diagnostics and therapeutic delivery systems,Fig.27(A)Schematic illustration of the core/shell separation process dissociation of the shells and cross-linking of the cores and(B)schematic depiction of the synthetic approach to controlled formation of(multilayered),hydrogel,particles.,Example four,a,Schematic illustration of a core-shell,microgel,which undergoes three regions of different swelling behavior(completely reversible process).,b,corresponding classification of previously mentioned regions in an exemplary,Rh(T,)-diagram of a core-shell,microgel,system with 10 mol%cross-linked cores.In region I we find a restricted shell collapse,while region II covers the linear swelling behavior.Region III indicates the occurrence of an active core collapse.,Zeiser,et al.,PNIPMAM-,co-,PNNPAM.In the region between 25 and 41,the response of the particles is directly proportional to the temperature,。,Example five,Peng,et al.,studied a novel approach for preparing hollow,PSt,particles by seed emulsion polymerization.The particles are composed of,PNIPAM-,co,-,PSt,and Hollow particles have shown potential applications in,drug,delivery,catalysts,controlled release etc.,Fig.30 Preparation of hollow particles with PNIPAM,microgels,as the cores.,CSP features,7.Applications,colloidal stability,three dimensional networks,dispersed,particles,External stimuli,(temperature,ionic strength,pH,external stress,solvent nature),Drug delivery,Optoelectric,switches,Environmental,cleanup,Industry,Medicine,Surface coating,others,Application