材料科学进展 张奇

1、张奇材料发展电卡材料多孔膜石墨烯“有些事不懂，就先放下，不急，假以时日，像是枝头的葡萄，自然会熟，落下来，尝了，就懂了。”材料发展历史材料革命材料研究进展材料分类智能材料铝（金属材料）混凝土（复合材料）天然橡胶（高分子材料）皮革（生物材料）人类文明的发展水平很大程度上取决于该文明所处时期的材料的特征和功能人造粘土制品、天然金属玻璃、陶瓷、青铜、铁钢、合金、聚合物有机化学的发展 1825年， 德国化学家维勒制备了尿素 1856年， 英国化学家博金合成染料 马尾紫 19世纪90年代称为“紫红色十年”， 这期间诞生了有机化学的另一分支 聚合物化学， 这一领域对新材料的发展产生了巨大的影响新材料的发现

2、 1865年， 英国发明家亚历山大 帕克斯，硝酸纤维素 1900年， 美国化学家贝兰德， 酚醛塑料20世纪20-30年代许多聚合物新材料的发明和商品化，包括：脲醛塑料、聚氯乙烯、聚苯乙烯、尼龙、聚甲基丙烯酸甲酯、聚乙烯、密胺塑料等。新金属的发展 铁碳合金熟铁铸铁碳钢英国冶金学家 - 亨利 贝莫西现代炼钢法：向熔化的铁水中吹入热空气，可得到含碳比例适当的钢铁与各种金属的合金 1868年，苏格兰冶金学家马歇特在贝莫西钢中加入少量钨， 使其硬度更大，韧性更好，使用寿命更长。 1819年，铬合金钢 1912年， 不锈钢 1905，镍铬铁合金 （美国工程师玛希发明，热电丝）其它非铁合金 铝铜镁锰合金 硬

3、铝，1908年，德国工程师维尔姆发明。之后Al-Cu-Mg合金系、Al-Zn-Mg-(Cu)合金系、Al-Li合金系相继发明。 镍铬合金 镍钛合金 铜合金 镁合金新型材料师法自然的材料复合材料生物材料人工合成材料智能材料光学材料纳米材料 材料研究目前最具有发展前景的领域是纳米材料。科学家将采用自下而上的顺序从分子和原子层次来合成新物质。纳米技术不仅能够对现有材料进行变革，同时还能够为新的化合物的设计和制造提供新的方式。材料分类化学状态物理性质用途组成物理效应状态材料金属材料非金属材料陶瓷材料高分子材料有机材料无机物材料高强度耐高温超硬导电绝缘磁性透光半导体导电橡胶不锈钢铝箔复合材料螺母单晶硅透

4、光混凝土铁氧体环氧树脂材料单晶多晶非晶态准晶态材料压电热电铁电光电电光声光磁光激光材料单组分复合材料研究制备技术计算机辅助设计检测工艺应用研究实验室实际应用改进寿命定义能感知外界的变化后以某种形式对其作出反应，从而改变自己的行为的材料种类 压电和电致伸缩材料、磁致伸缩材料、现状记忆合金、电流变液和磁流变液材料、光致变色或热致变色材料现状记忆合金 有记忆功能的合金材料是1963年美国海军军悈实验室的研究人员发现的具有现状记忆功能的合金一般都具有马氏体相变，将合金加热到相变温度时，就能从马氏体结构转变为奥氏体结构，完全恢复原来的形状。加热会变直的勺子镍系合金：Ni-Ti，Ni-Ti-Pd，Ni-T

5、i-Fe铜系合金：Cu-Zn-Al，Cu-Al-Ni铁系合金：Fe-Pt，Fe-Cr-Ni，Fe-Mn-Si形状记忆合金的应用形状记忆合金被广泛地应用于卫星、航空、生物工程、医药、能源和自动化等方面。如：“阿波罗”11号登月舱携带的天线。先在相变温度以上把天线做好，然后在相变温度以下把它压缩成一团，塞进登月舱，到登月舱进入轨道后，加热天线到相变温度以上，天线完全打开。压电和电致伸缩材料 压电效应是1880年杰克斯 、居里俩兄弟首先发现的。 压电效应：某些电介质在沿一定方向上受到外力的作用而变形时，其内部会产生极化现象，同时在它的两个相对表面上出现正负相反的电荷。当外力去掉后，它又会恢复到不带电

6、的状态，这种现象称为正压电效应。当作用力的方向改变时，电荷的极性也随之改变。相反，当在电介质的极化方向上施加电场，这些电介质也会发生变形，电场去掉后，电介质的变形随之消失，这种现象称为逆压电效应。 逆压电效应属于一种典型的电致伸缩效应压电材料压电效应 压电效应是某些材料的特性（尤其是某些晶体和特定的陶瓷，包括骨髓），即加载机械应力时能够产生出电势 （正压电效应）。这样电荷在晶格上可能表现为是分开的。如果材料不短路，被作用的电荷使得材料产生出电压。 压电效应是可逆的，在那些存在直接压电效应（即当施加压力时产生电）的材料中，同样也存在相反的压电效应（即施加电场时产生出压力和/或张力）（逆压电效应）

7、。正压电效应 当对压电材料施以物理压力时，材料体内之电偶极矩会因压缩而变短，此时压电材料为抵抗这变化会在材料相对的表面上产生等量正负电荷，以保持原状。这种由于形变而产生电极化的现象称为“正压电效应”。正压电效应实质上是机械能转化为电能的过程。P= d其中，P为晶体的电极化率，单位是C/m2， d为压电常数，单位是C/N， 为应力，单位是N/m2。逆压电效应 当在压电材料表面施加电场（电压），因电场作用时电偶极矩会被拉长，压电材料为抵抗变化，会沿电场方向伸长。这种通过电场作用而产生机械形变的过程称为“逆压电效应”。逆压电效应实质上是电能转化为机械能的过程。S = dt E其中，S为晶体的杨氏模量

8、， dt为压电常数，单位是m/V，E为电场强度，单位是V/m。 压电晶体目前用于很多途径，其中一种是致动器： 由于晶体的宽度只要稍微有一点微小的变化就会相应的出现极高的电压，这个宽度的变化比千分尺还要精确，使得压电晶体成为用来极其准确的定位物体的最重要的工具这就是他们在致动器中的用途。 扬声器：电压转换为压电高分子膜的机械运动。 压电马达：压电元件用定向力驱动一个轴，使之旋转。由于是非常小的距离，压电马达做为高精度马达从而取代步进电机。 原子力显微镜和扫描隧道显微镜采用逆压电保持传感针靠近探针。 喷墨打印机：在某些喷墨打印机，特别是那些爱普生生产的，压电晶体是用来控制从喷墨头到纸张上墨水的流量

9、。柴油发动机：高性能的共轨柴油发动机使用压电喷油器，最先由罗伯特博世有限公司研发的，替代了更常见的电磁阀装置。压电材料的研究发展方向 驰豫型铁电单晶 压电复合材料 主要用于水听器，理论未完全建立，开发未充分发掘 高居里温度复合材料 必须在高温下具有压电性能 三元及多元系压电材料 压电薄膜 满足器件的小型化需求 细晶粒压电陶瓷压电材料的研究发展方向 无铅压电材料目前所用的压电材料绝大部分为铅基压电陶瓷，对人和环境有污染。无铅压电材料的性能还远远落后于铅基压电陶瓷材料，要达到铅基压电材料的性能还需要做大量的研究工作。日本在无铅压电材料研究开发上的论文和专利最多。铁电材料的主要特征值铁电体自发极化电

10、畴电滞回线居里温度介电反常自发极化在没有外施电场的情况下，晶体的正、负电荷中心也不重合而呈现电偶极矩这种现象称为自发极化。凡是呈现自发极化，并且自发极化的方向能因施加外场而改变的晶体称为铁电体(ferroelectrics)。 电畴 具有自发极化的晶体中存在一些自发极化取向一致的微小区域，称为电畴。两畴之间的界壁称为畴壁。若两个电畴的自发极化方向互成90，则其畴壁叫90畴壁。此外，还有180畴壁等。18090电滞回线铁电体的基本特征是在外电场的作用下，晶体的自发极化强度能随外电场而转向。从电畴的角度出发，在无外场时，各小电畴在晶体中的分布是无规律的，晶体呈电中性，也即从宏观的整体来说，晶体是不

11、极化的。但当有外电场加于晶体时，由于电场同方向的电畴增长，逆电场方向的电畴逐渐消失，以及由于其他方向分布的电畴转向电场方向等原因，使极化矢量P随电场E的增大而增加，且它们之间的关系曲线完全相似于铁磁性物质的HB曲线，这种曲线叫做电滞回线。 居里温度 居里温度是指材料从铁电性转变成非铁电性的温度。TTc介电反常BaTiO3铁电体的研究历史与现状 1920年，法国人瓦拉赛克 （Valasek）发现罗息盐（酒石酸甲纳），具有铁电性。 第一阶段：1920-1939, 发现了两种铁电结构， 即罗息盐和KH2PO4系列。 第二阶段：1940-1958，铁电热力学理论。 第三阶段：1959-1970年代，钙

12、态矿时期-铁电软模理论出现。 第四阶段：1980年代-今，铁电薄膜及器件时期-小型化。压电体热释电体铁电体介电体热释电效应 （pyroelectric effect)在某些绝缘物质中，由于温度的变化引起极状态改变的现象称为热释电效应。Ps =TPs为自发式极化强度变化量；T为温度变化；为热释电系数。热释电系数 = Ps/T=dPs/dTPTTcVIZT1T2T1T1T1T2热释电材料 LiTaO3单晶 PZT陶瓷 硫酸三甘钛电卡效应是在极性材料中因外电场的改变从而导致极化状态的改变而产生的绝热温度或等温熵的改变。When an electric field is applied to or r

13、emoved from a dielectric material, under adiabatic conditions, it will induce a change in the polarization and consequently a change in the entropy and temperature in the material. Such an electric field-induced temperature and entropy change in a dielectric material is known as the electrocaloric e

14、ffect (ECE). -3-好心情T1 (= Room T), S1 E1 (=0) T2 (= T1 + T), S1E2 = EmaxT1, S2 ( S1)S0S = 0S = 0S(E1,T1) = S(E2,T2)S(E2,T1) = S(E1,T3)All solid-state cooling devicesOn-chip devices Refrigerationfridges, air-conditioners (more environmentally friendly)heaterKapton filmECE film+-IR sensor电卡测试装置cccSTQHH

15、hSTQA-B Adiabatic polarizationB-C Heat transferC-D Adiabatic depolarizationD-A Entropy transferhcgenSSSgenhcchSTSTTW)(WQCOPcchcCRTTTCOPCRCOPCOP)(11chcgenhTTSSTcchhchSTSTQQWNet Electrical Energy:Coefficient of Performance (COP): For ideal reversible cycle:hcSSFor real cycle:Why ECE Based Cooling Devi

16、ces Are Interesting?Energy and Environment Refrigeration, air-conditioning, and cooling overall consume more than 20 % of electricity in the developed countries Air conditioning is a key driver of peak electricity demand The mechanical Vapor Compression Cycle cooling (VCC) devices have COP 2 to 4 (

17、70% of Carnot efficient) Environmental concerns: the refrigerant gases (HFC) in the mechanical VCC cooling devices are strong greenhouse gases. They contribute to about 25% of total greenhouse gases!In bulk ceramics, it was found that- T a few Kelvin (2.5 K in Pb0.99Nb0.02(Zr0.75Sn0.20Ti0.05)O3), -

18、A small change of heat 0.2 kJ kg-1 and - A small breakdown field 50 kVcm-1.All of these are too small to be of practical use.Electrocaloric properties of PZT thin filmsassociated with the FE-PE phase transitionA.S. Mischenko，Q. Zhang, et al. Science 311, 1270 (2006)Hysteresis losses 4%211EEEdETPCTTJ

19、oule heating 10-3 K220CCostEnvironment ImpactEfficiency/PowerCostEnvironment Impact)(11chcgenhTTSST21EEpdESHigh Breakdown Field(Thin films)High pyroelectric coefficient(Phase transition)21EEpdECTT-40-2002040P (C cm-2)-1000 -5000500 1000E (kV cm-1)21C-40-2002040P (C cm-2)-1000 -5000500 1000E (kV cm-1

20、)9C-40-2002040P (C cm-2)-1000 -5000500 1000E (kV cm-1)59C-40-2002040P (C cm-2)-1000 -5000500 1000E (kV cm-1)80C(Partially-ordered)T. M. Correia, et al. J. of Phys. D: Appl. Phys. 44, 165407 (2011).(Partially-ordered)32282420161284P (C cm-2)120100806040200T (C)201296583774392E (kV cm-1) FC FH Cubic-s

21、pline fitDeviation from ideal reversible Carnot cycleMaterial irreversible processes Thermal hysteresis (first-order phase transitions, glassy state in relaxors,) Electrical hysteresisThermodynamic Cycle Losses during heat exchange-11-10-9-8-7-6-5-4-3-2-10S (K kg-1K-1)45403530252015105T (C) FC FH723

22、509434360723285210E (kV cm-1)509434360285210a)-11-10-9-8-7-6-5-4-3-2-10T (K)45403530252015105T (C)723509434360723285210E (kV cm-1)509434360285210b)Relaxor 0.93PbMg1/3Nb2/3O3-0.07PbTiO3 Thin FilmNon-ergodic phaseThermal HysteresisRelaxor 0.93PbMg1/3Nb2/3O3-0.07PbTiO3 Thin Film-20-1001020P (C cm-2)-75

23、0 -3750375750E (kV cm-1)70C-20-1001020P (C cm-2)-750 -3750375750E (kV cm-1)30C-20-1001020P (C cm-2)-750 -3750375750E (kV cm-1)18C-20-1001020P (C cm-2)-750 -3750375750E (kV cm-1) FC FH5C)(chcTTSRCFWHMSSdTRCmTThcCostEnvironment ImpactEfficiency/PowerRaw MaterialsThin Film growthOperationInexpensiveSol

24、-Gel method: Cost-effective techniqueLow-cost operating device (no need for expensive magnets like magnetocaloric refrigerants)CostEnvironment ImpactEfficiency/Power(Lead is a toxic element for which special facilities are required during handling in order to minimize risk to health and to the envir

25、onment.)Electrocaloric refrigeration do not involve harmful gasesLead-based electrocaloric thin filmsTitleIntroduction Why capture CO2 ? Sources of CO2 emission? CO2 separation technologiesGas separation technologies Basic concepts MembranesvMechanism of membrane separation processesvSelection of Me

26、mbranesvPermeabilityvSelectivityvPolymeric MembranesvInorganic MembranesvOther membranes ConclusionsRealize the CO2 separation mechanism by membranes.What are the advantages of the use of membranes for CO2 separation?Realize current development of polymeric and inorganic membranes.Realize the future

27、 development direction of membranes. 85% of the worlds trade energy needs is provided by mineral fuels that are largely responsible for the increase in CO2 emissions. Climate change is one of the most significant factors faced by humanity and society as a whole. With the current structure of global

28、power, there are no viable alternative energy sources to mineral fuels, capable to fully replace them.Why capture carbon?A rapid change of energy sources of non mineral origin would result in a major disruption to the infrastructure of energy supply, with significant consequences for the global econ

29、omy. The CO2 capture and storage (CCS) is seen as a fundamental and indispensable measure to reduce the environmental impacts associated with this potentially catastrophic phenomenon. Commercial CO2 capture technology that exists today is very expensive and energy intensive. It is necessary to devel

30、op technologies that will allow us to utilize the fossil fuels while reducing the emission of green house gases.This lecture presents a summary of membrance technology of capture/separation of CO2.Currently the largest single point sources of CO2 emission are power plants that produce streams of flu

31、e gas, exhausted combustion smoke, with CO2 concentrations of ca. 15% at 1 atm.Sources of CO2 emissionFossil fuel （化石燃料） Natural gas(power plant)Mixed gases reusetransportseparationCO2StorageIntroduction -CO2 Emission SourcesNatural gas generationMixed gasesCO2, CH4, H2, etc separationCO2Cryogenic d

32、istillationSorbent absorption （吸附剂吸附）Membrane Adsorption is the adhesion of atoms, ions, biomolecules or molecules of gas, liquid, or dissolved solids to a surface.Absorption in chemistry, is a physical or chemical phenomenon or a process in which atoms, molecules, or ions enter some bulk phase-gas,

33、 liquid or solid material.Adsorbent is a substance, usually porous in nature and with a high surface area that can adsorb substances onto its surface by intermolecular forces.Adsorbate the molecules or atoms being accumulated on the surface of the adsorbent. Surface energy the excess energy at the s

34、urface of a material compared to the bulk.Physisorption also called physical adsorption, is a process in which the electronic structure of the atom or molecule is barely perturbed upon adsorption.Chemisorption is a sub-class of adsorption, driven by a chemical occurring at the exposed surface. A new

35、 chemical species is generated at the adsorbent surface (e.g. corrosion, metallic oxidation). The strong interaction between the adsorbate and the substrate surface creates new types of electronic bonds ionic or covalent, depending on the reactive chemical species involved.Van der Waals force is the

36、 sum of the attractive or repulsive forces between molecules (or between parts of the same molecule) other than those due to covalent bonds or to the electrostatic interaction of ions with one another or with neutral molecules. Micropores, of dimensions below 2 nm, Mesopores, between 2 and 50 nm, an

37、d Macropores, 50 nm.86 Gas separation membranes allow one component in a gas stream to pass through faster than the others. There are many different types of gas separation membrane, including porous inorganic membranes, palladium membranes, polymeric membranes and zeolites. MembranesMembranes canno

38、t usually achieve high degrees of separation, so multiple stages and/or recycle of one of the streams is necessary. This leads to increased complexity, energy consumption and costs.89The transport of chemical species through a membrane occurs when there is a driving force acting on it.In general, ch

39、emical potential gradient is the driving force.Chemical potential gradient can be expressed in terms of pressure gradient and concentration gradient.A successful membrane allows the desired gas molecule to adsorb to the surface on one side, often at higher pressure (solubility). The molecule then ab

40、sorbs into the membrane interior, eventually reaching the other side of the membrane (mobility) where it can desorb under different conditions, such as low pressure.Solution-diffusion mechanismo the separation of permeates due to two factorsv Solubility (thermodynamic factor)v mobility of the permea

41、tes into the membrane matrix diffusion (kinetic factor)SolubilityMobilityIntegral CompositeisotropicAnisotropicdCDJJ : the specific gas flowD: diffusion coefficient (m2 s-1)C: gas concentration in material (mol m-3)d: film thicknessThe permeability per unit thickness:PtAQtyPJdSDdPegas1The selectivit

42、y of a membrane 2222/NCONCOdPedPeySelectivitNCO22Select the most suitable material for separating gas mixtures, leading to better selectivity and permeability ratio.Study the yield and purity of the product. This means that the permeability and selectivity for the transport of gas should be high.The

43、 anisotropic membrane with appropriate morphology for gas separation must present a coating, free from defects, favouring the transport solution by diffusion.In order to obtain efficiency, a reduced coating thickness should be used, which provides higher permeate flux.Porous sub layer with low resis

44、tance to the transport of permeate. This sub layer must operate only as a porous support, providing mechanic strength to finish.The challenge for polymer chemists is to develop polymers with much higher permeability, whilst retaining adequate selectivity and meeting other requirements, such as proce

45、ssability and long-term stability. Many polymers have been investigated as gas separation membrane materials, but up to now only a handful have found commercial success. These includeq Rubbery polymers v Poly(dimethylsiloxane)q Glassy polymersv Polysulfonev Cellulose acetatev Polyimidev Poly(phenyle

46、ne oxide)Glassy polymer contains micropores (2 nm) high selectivity good mechanic strengthPlot of selectivity vs permeabilitySolid line 1991Dashed Line 2008 PTMSP; polyacetylene 2e; Teflon AF2400; + poly(trimethylsilyl norbornene) PIM-1; PIM-1 after methanol treatment 6FDA-DMN polyimide PIM-PI-8Perf

47、ormance of polymeric membranes separating CO2/N2(Powell and Qiao, 2006)Porous aluminaPolymer precursor solutionCarbonized under vacuum or high T The CO2 affinity of a typical carbon membrane was enhanced to improve the separation performance of the membrane based on the concept of Scheme I. Zeolites

48、 are crystalline aluminosilicates with a uniform pore structure and a minimum channel diameter range of 0.3 to 1.0 nm. Selectively adsorb molecules by size and polarity.Separation occurs in zeolite membranes by both molecular sieving and surface diffusion mechanisms.Zeolite membranesIncorporation of

49、 molecular sieves within a polymer membrane possibly provides both the processibility of polymers and selectivity of molecular sieves.The permeability of a gas through a zeolite-filled polymeric membrane depends on the intrinsic properties of the zeolite and polymer.Examples: polyimide-carbon molecu

50、lar sieve; polyimide-silica; etc.Mixed-matrix membranesA porous inorganic support material is surface-modified with chemicals which have good affinity with CO2.This helps CO2 separation in two ways: porous inorganic materials allow large flux while the chemical provides selectivity.Examples: Trichlo

51、rosilane-alumina; tetrapropylammonium-silica, etc.Hybrid membranesPolymeric membranesRelatively easy to manufacture and well-suited for low temperature applications.By carbonizing these polymeric materials it is possible to obtain a molecular sieve capability.Inorganic membranesMuch greater thermal

52、and chemical stability.Fossil fuel continues to be the primary energy source, at least for this century. There are many technical options for separation and /or capture of CO2 from combustion flue gas and other industrial effluents. Membrane separation processes provide several advantages over other

53、 conventional separation techniques; A membrane combining high flux, high selectivity and high stability is required, but is not realistic at this stage. Mixed-matrix membranes provide hopes. Membrane process as energy-saving, space saving, easy to scale-up, could be the future technology for CO2 se

54、paration.Basic definitionsCarbonIntroductionOccurrence and productionPropertiesPotential applicationsExamplesConclusionGraphene a one-atom-thick plannar sheet of carbon atoms that are densely packed in a honeycomb crystal lattice.Graphite many graphene sheets stack together2D crystal a single atomic

55、 plane is a 2D crystal, whereas 100 layers should be considered as a thin film of a 3D material. Composite the material is made of two or more different parts; one or more discontinuous phases distributed in one continuous phase.STM image of graphite surface atomsSide view of layer stackingGraphite

56、has a layered, planar structure. In each layer, the carbon atoms are arranged in a hexagonal lattice with separation of 0.142 nm, and the distance between planes is 0.335 nm.Graphite is an electrical conductor, a semimetal.Graphite is the most stable form of carbon under standard conditions (273 C,

57、0.986 atm. by IUPAC).IUPAC International Union of Pure and Applied ChemistryGraphite can conduct electricity due to the vast electron delocalization within the carbon layers. These valence electrons are free to move, so are able to conduct electricity. However, the electricity is only conducted with

58、in the plane of the layers. face-centered cubic crystal structure less stable than graphite strong covalent bonding between its atoms the highest hardness and thermal conductivity of any bulk materialDiamond （钻石）Graphite（石墨）Graphene or graphite rolls and forms carbon nanotubes, the former single wal

59、l and the later multi-walls. 碳纳米管The hexagonal grid structure of graphene Monolayer graphene was first obtained as a transferable material in 2004. This development has recently culminated in the award of the 2010 Nobel Prize to Andre Geim and Konstantin Novoselov of the University of Manchester, UK

60、, for “groundbreaking experiments regarding the two-dimensional material graphene.” Graphene can be wrapped up into 0D fullerences, rolled into 1D nanotubes or stacked into 3D graphite. Nature, 2007,6, 183.石墨碳纳米管石墨烯足球烯In 2004, the researchers in the University of Manchester, obtained graphene by mec