pickering乳液-颗粒在油水界面吸附

张春桥2015-5Emulsionstabilizedbyparticlescontents•InflunenceofparticlewettabilityonEmulsion•EffectofparticleConcentration•EffectoforiginalLocation&Φw•Effectofelectrolyteonemulsion•EffectofpH&Temperatureonemulsion1.InflunenceofparticlewettabilityontypeandstabilityofEmulsionBinks,B.P.Langmuir,2000,16,8622-863112/2)cos1(AWOWRGImmersiontimeat22°Cofsixsilicapowdersinmethanol-watermixturesofdifferentcomposition2Binks,B.P.Langmuir,2000,16,8622-86313Binks,B.P.Langmuir,2000,16,8622-86314particlesinitialintolueneN.Yanetal.ColloidsandSurfacesA:Physicochem.Eng.Aspects193(2001)97–107settlingbehavior5Settlingofnanospheres-intoluenesuspension(5kgm-3nanospheres）N.Yanetal.ColloidsandSurfacesA:Physicochem.Eng.Aspects193(2001)97–107N.Yanetal.ColloidsandSurfacesA:Physicochem.Eng.Aspects193(2001)97–1076settlingbehavior5kgm-3glassbeads;diameterofglassbeads:2μm7fumeSiO2-water-cyclicsilicone(D5)Binks,B.P.Silica-StabilizedEmulsions,Langmuir,Vol.21,No.8,2005(oil:water=1:1)particleorigianlinoil2.EffectofparticleConcentration36%（强疏水）和87%（强亲水）:润湿性决定乳液类型（1：1）相反转：57%--1wt%；71%--2.5wt%①C↑，d↓，sedimentationstability↑(d--coverage，η-network)②Uniformity:0.22→0.95（PK乳液特点：单分散性最好的是最大的乳液滴）8Binks,B.P.Langmuir,Vol.21,No.8,200536%SiOHparticlesinitiallylocationBinks,B.P.Langmuir,Vol.21,No.8,20059inoilVS.inwater71%SiOH10d越大，U越小(uniformity单分散性越好）295μm--0.1wt%60μm--1wt%20μm--5wt%71%SiOHinwaterO/WBinks,B.P.Langmuir,Vol.21,No.8,200511Binks,B.P.Silica-StabilizedEmulsions,Langmuir,Vol.21,No.8,2005shearrates10(○),30(□),and100s-1△)Rheologyandparticlestructure部分疏水颗粒先分散在油相，颗粒体现较强疏水性部分疏水颗粒先分散在水相，solvation作用，体现亲水性η与液相极性有关絮凝程度：aggregates→flocs→three-dimensionalnetwork→gel12B.P.Binks.Langmuir2003,19,4905-49122wt%particles三辛酸甘油酯（polar）SiO2（79.9%Si-OH）3.EffectoforiginalLocation&ΦwinWater：Φw=0.225；随φw不断增加，发生W/O→O/WinOil：Φw=0.625；W/O→W/O/WΦw=0.5inwater：O/Winoil:W/Oinwaterinoilinoilφw=0.6W/Oφw=0.65w/o/winoilφw=0.1、0.4、0.6(w/o)；0.65、0.7、0.8(w/o/w)inwaterφw=0.1、0.2(w/o)；0.25、0.4、0.6、0.8(o/w)13B.P.Binks.Langmuir2003,19,4905-491214inwaterW/OΦw=0.20O/WΦw=0.25O/WΦw=0.60φo↑，d↓,U↑制备单分散乳液方法：固定颗粒浓度，增加φoB.P.Binks.Langmuir2003,19,4905-49124.Effectofelectrolyteonemulsion2mMNaClpurewater84%SiOHfumedsilicasuspension+硅油creamingBoundarycreamingstability仪器：DiStA24Binks,B.P.PCCP,2007,9,6398–640415Emulsion00.005mM1mM2mM16Binks,B.P.PCCP,2007,9,6398–6404a)0b)2mMc)100mM4wt%W：O=1：1O/Wlargestoragemodulusindicationofgellingoftheemulsion17Binks,B.P.PCCP,2007,9,6398–6404shearrate10s-102mM5mM100mMSuspension1)不加盐：notaclearliquildattopofthesample；2)加盐：distinctsedimentationboundary3)浓度越高，絮凝越强，从而导致底部颗粒浓度变化越小flocs→attractiveinteraction→dimentionalnetwork→viscosity↑→sedimentslowdown18Binks,B.P.PCCP,2007,9,6398–6404suspensionVS.emulsion--C.F.C19Binks,B.P.PCCP,2007,9,6398–64045.EffectofpH&Temperatureonemulsion微胶PNIPAM：NIPAM、MBA、MMA、MRD体系组成：辛醇(30%)，PNIPAM(1wt%)，水Binks,B.P.CC,2005,331–33320pH21Binks,B.P.CC,2005,331–333Temperatureoctanol-inwateremulsionstabilizedbymicrogelparticlesatpH6.1and9.422Binks,B.P.CC,2005,331–333pH&TFig.4ThestabilizingefficiencyofPNIPAMmicrogelparticlesforoctanol-in-wateremulsionsasafunctionofpHandtemperature.■：Stable，●：Unstable,，◆：Phaseseparation.(Arrowsindicatetheprobedtransitions23Binks,B.P.CC,2005,331–333pH引起的双重相反转HaraldD.H.Stover.Langmuir2008,24,13237-1324024谢谢请多多批评指正！φw=0.5inwtaer:W/O/W(低颗粒浓度)inoil:W/O/W(低颗粒浓度)多重产生原因：聚并的液滴在搅拌过程中将连续相包含在其内部，从而引起新生成界面不完全覆盖。coalescenceofdropswithinclusionofthecontinuousphaseduringthemixingprocessasaresultofinsufficientcoverageoffreshlyformedinterfaces.forthesameamoutofshear,atlowparticleconcentrationtherearenotenoughparticlespresenttofullycovertheoil-waterinterfacesproduced,andsooildropcoalesceeasilywithinclusionofwater,thusgrowingandredcingtheinterfacialarea.B.P.Binks.Langmuir2003,19,4905-4912