第六章 疏水材料--超疏水ppt课件

.,Supperrepellentmaterial,.,1Wettability,Youngsequation:cos=(SVSL)/LVHydrophobic:90;Hydrophilic：90.,Wettabilityisafundamentalpropertyofmaterialsurfaces,.,Watercontactangle(WCA)largerthan150andextremelylowWCAhysteresisorslidinganglelessthan10.,Superhydrophobicity,.,Slidingangle,mg(sin)/=(cosa-cosr)aAdvancingcontactangle,rRecedingcontactangle,m-Thequalityofwaterdrop，g-Accelerationofgravity，-Diameterofwaterdrop，-SurfaceEnergyofwaterdrop。m，g，areconstant，then：sincosacosr.,.,Awidespectrumofapplications,.,soysauce,.,.,.,Watercollectorinthedesert,.,.,Antifoulingcoating,Theundesirableaccumulationofmicroorganisms,plants,andanimalsonartificialsurfacesimmersedinseawater.Highfrictionalresistanceandfuelconsumption,duetogeneratedroughness,Deteriorationofthecoatingsothatcorrosion,discolouration,andalterationoftheelectricalconductivityofthematerialarefavoured.,.,Lowsurfaceenergycoatingformitigatingmarinebiologicalfouling,Antifoulingcoating,.,Dragreduction,.,.,Self-cleaningmaterials,.,Antifrost,.,Antifoggingsurfaces,.,局部放大,Oilwaterseparation,.,Supperrepellentmaterialinnature,.,出淤泥而不染，濯清涟而不妖。-宋.周敦颐爱莲说,.,超疏水的荷叶和表面结构（a)球形的水滴滴在荷叶表面（b)荷叶表面大面积的微结构（c)荷叶表面单个乳突（d）荷叶表面的纳米结构,Lotuseffect,.,Cicadaswings,蝉翼表面由规则排列的纳米柱状结构组成纳米柱的直径大约在80nm，纳米柱的间距大约在180nm规则排列纳米突起所构建的粗糙度使其表面稳定吸附了一层空气膜，诱导了其超疏水的性质，从而确保了自清洁功能。,.,Butterflywings,.,.,2、ThetheoreticsofSupperrepellentmaterial,Wettability,Cassiemodel,Wenzelmodel,Youngsequation,.,Forsmooth,flat,uniformsolidsurface,therelationshipbetweencontactangleandsurfaceenergycanbedescribedbyYongsequation(ThomasYoung,1805):cos=(SVSL)/LV,Interfacialtension:SV、SL、LV,Yongsequation,.,Hydrophobicsurface,Thesurfacefreeenergyofmaterialsisrelatedtothespeciesandtheconcentrationofthefunctionalsurfacegroups,.,Functionalsurface,Hydrophilicgroups:OH、CHO、COOH、NH2Hydrophobicgroups：CnH2n+1、CH=CH2、C6H5、X、NO2CF3,.,Fluorinatedpolymer,CH2(36dyncm-1)CH3(30dyncm-1)CF2(23dyncm-1)CF3(15dyncm-1)ThereasonofchoosingfluorosiliconeLowsurfaceenergyandhighsurface-activeofCF3groupImprovestheadhesionandcompatibility,.,self-assembly,.,Forsmooth,flat,uniformsolidsurface,thehighestcontactangleisonly119。,.,Realsolidsurfacewithconcave-convexstructure,Wenzelmodel,Cassiemodel,.,Cos*=,=rCOS,Wenzelmodel：,.,Cos*=,=rCOS,Providing=110，ifr0.53，*willbelargerthan150,Wenzelmodel,.,Cassiemodel,.,Cos=fcos+(1-f)cos180=fcos+f-1,Areafractionf=a/(a+b),letsassumethat=110，iffislessthan0.2,willbelargerthan150.,Cassiemodel,ProvidingCAbetweenliqiudandairis180,.,PANNanofibermaterial,.,.,Self-cleaningeffect,Dirt,.,.,3、ThefabricationofSupperrepellentsurface,Modifyingaroughsurfaceschemicalcomponents,.,TurningaSurfaceSuper-RepellentEventoCompletelyWettingLiquids,Tingyi“Leo”Liu,etal.,Science,vol.346,pp.1096-1100,2014.,.,Templatemethod,.,Etching,.,McCarthy等在聚四氟乙烯(PTFE)存在下,用射频等离子体刻蚀聚丙烯(PP)制备出粗糙表面。表面与水的前进角/后退角可达A/R=172/169。,利用射频等离子体刻蚀法在不同刻蚀时间得到的聚丙烯扫描电子形貌图:(a)0min,(b)30min,(c)60min,(d)90min,(e)120min,(f)180min,.,Chen等利用纳米球刻蚀的方法首先得到了排列整齐的单层聚苯乙烯(PS)纳米珠阵列,再用氧等离子体处理以进一步减小纳米珠的尺寸从而得到粗糙表面。在其表面覆盖20nm厚的金膜并用十八硫醇(ODT)进行修饰可以增强其疏水性。通过调整PS纳米珠的直径(440-190nm)可以控制表面接触角的大小(132-168)。,氧等离子体处理后的超疏水PS纳米珠阵列表面,.,.,Chemicalvapordeposition,江雷等利用化学气相沉积法(CVD)在石英基底上制备了各种图案结构的阵列碳纳米管膜,结果表明,水在这些膜表面的接触角都大于160,滚动角都小于5,纳米结构与微米结构在表面的阶层排列被认为是产生这种高接触角、低滚动角的原因。,.,4Researchplan,Inordertofabricatesuperhydrophobicorsuperhydrophilicsurfacesbasedonsub-micronstructures,IthinkmyresearchinUWcanbedividedintothreestages.,.,Firstly,thefabricationofartificialstructuredsurface.Severalartificialstructuredsurfaceshavebeendisgined.Ifthesenanopillarandmushroomshapednanopillarsarraywithpieceof10mm10mmcanbepreparedbyelectroplatecopperornickelnanopillars?,.,.,Secondly,modifyitscomponentsbysurfacefluorination.,.,Lastly,thefabricationofhierarchicalstructures.Ifthepropertyofabovestructuredsurfaceaftersurfacefluorinationcannotmeetsuperhydrophobicorsuperhydrophilicrequirement,Iwillincreasesurfaceroughnessbypreparinghierarchicalstructuresonaboveartificialstructuredsurface.,.,.,Somequestions,Experimentrigandseveral