《基础化学》英文教学课件：chapter-5.ppt

1、Chapter 5.5-1.colloids 5-2.Sol 5-3.Macromolecular solution 5-4.Surfactants and associated colloids1 1 胶体分散系胶体分散系明确明确分散系分散系；分散相分散相；分散介质分散介质；均相体系均相体系；非均相体系非均相体系；相相的概念；的概念；明确明确比表面比表面；表面能表面能的概念；的概念；明确明确 分散相的分散相的分类方法分类方法；2 2 溶胶溶胶明确明确 溶胶溶胶；电泳电泳；电渗；临界聚沉浓度电渗；临界聚沉浓度的概念；的概念；理解溶胶的理解溶胶的性质性质：光学性质；动力学性质；电学性质光学性质；

2、动力学性质；电学性质明确溶胶的明确溶胶的结构结构：胶核胶核；胶粒胶粒；吸附层吸附层；扩散层扩散层；双电层双电层概念概念理解胶粒的理解胶粒的电属性电属性；理解溶胶的理解溶胶的稳定性稳定性及及聚沉聚沉；Learning Objectives3 3 高分子溶液高分子溶液明确明确 高分子溶液高分子溶液；等电点等电点的概念；的概念；理解理解 高分子溶液的属性；高分子溶液的属性；理解理解 盐析，电泳盐析，电泳分离和纯化蛋白分离和纯化蛋白的机制；的机制；4 4 表面活性剂和缔合胶体表面活性剂和缔合胶体明确明确 表面能表面能；表面张力表面张力；增溶增溶的概念；的概念；明确明确 胶束胶束；临界胶束浓度临界胶束浓

3、度；缔合胶体缔合胶体的概念；的概念；理解理解 表面活性剂的分类；表面活性剂的分类；1.ColloidsA solution is a homogeneous()mixture of two or more substances,consisting of ions or molecules.A colloid()is a dispersion of particles(1 100 nm)of one substance throughout another substance or solution.Concept introduction:NaCl aqueous solution:Na+,

4、Cl-,H2OFog is an example of a colloid:it consists of very small water droplets in air.Proteins,nucleic acids,blood,body fluid,cell.T.Thomas Graham(18051869)Peter P.von Weymarn(1879 1935)扩散速度小，不能透过半透膜，溶剂蒸发后扩散速度小，不能透过半透膜，溶剂蒸发后不结晶，而是形成无定形胶状物的物质。不结晶，而是形成无定形胶状物的物质。T.Thomas Graham(18051869)任何能结晶的物质在任何能结晶的

5、物质在一定介质中用适当的一定介质中用适当的方法都能成为方法都能成为胶体胶体胶体胶体是物质的一种分散状态的概念是物质的一种分散状态的概念1.Colloids1.ColloidsI.Dispersed systemDispersed phase(分散相分散相):to be dispersed,discontinuousDispersed medium(分散介质分散介质):to disperse,continuousA dispersed system()is formed by dispersing one or more substances throughout another substan

6、ce.D Di is sp pe er rs se ed d s sy ys st te em m F Fo og g N Na aC Cl l s so ol lu ut ti io on n Dispersed phase Water droplets NaCl Dispersed medium air water 1.ColloidsClassification of dispersed systems:A heterogeneous system()is a mixture that consists of physically distinct parts,each with dif

7、ferent properties.A homogeneous system(,also known as a solution)is a mixture that is uniform in its properties throughout given samples.K2CrO4+Fe fillings1.ColloidsA phase()is one of several different homogeneous materials present in the portion of matter under study.These heterogeneous systems all

8、 consist of two different phases.K2CrO4+Fe fillings1.ColloidsClassification of dispersed systems:Classification according to the size of dispersed phase.Size Dispersed system Composition of dispersed phase Properties 100nm Coarsely-dispersed system(粗粗分散分散体系体系)Coarse particles(粗粗粒子粒子)Heterogeneous no

9、nstable Sol 固固-液液 Sol 液液-气气Sol 固固-气气Coloured stained glass Sol 固固-固固乳状液乳状液Milky Way?凝胶凝胶The Milky Way is the galaxy that contains our Solar System.An image of the Milky Ways Galactic Center in the night sky above Paranal Observatory可怜织女星，化为马郎妇。可怜织女星，化为马郎妇。乌鹊疑不来，迢迢牛奶路。乌鹊疑不来，迢迢牛奶路。-出自鲁迅的出自鲁迅的教授杂咏四首教授杂

10、咏四首 The Milky Way is the galaxy that contains our Solar System.鲁迅鲁迅(1881(1881年年9 9月月2525日日-1936-1936年年1010月月2020日）日）呐喊呐喊狂人日记狂人日记阿阿Q Q正传正传1.ColloidsII.Colloid dispersed systemA is a dispersion of particles(1 100 nm)of one substance(the dispersed phase)throughout another substance or solution(the disp

11、ersed medium or the continuous phase().Sol()Macromolecular solution()Associated colloid()1.Colloids1.SolA is a colloid consisting of solid particles(collection of atoms,molecules,or ions)dispersed in a liquid.heterogeneous and unstable1.ColloidsDegree of dispersion():A cube with a size of 1 cm:130cm

12、6cm1cm1cm16S:surface area occupied by the substance of a unit volume.VSS 0surface areavolume1 cm1.ColloidsDisperse the cube to cubes with a size of 1 m,the number of smaller cubes is:123310m1cm1N143120cm106cm110m1m16SThen,Disperse the cube to cubes with a size of 1 nm,the number of smaller cubes is:

13、213310nm1cm1N173210cm106cm110nm1nm16SThen,1 cm1 m1 nm1.ColloidsA molecule at the surface experiences a net force toward the interior of the liquid,whereas a molecule in the interior experiences no net force.There is a tendency for the surface area of a liquid to be reduced as much as possible.This e

14、xplains why falling raindrops are nearly spherical(the sphere has the smallest surface area for a given volume of any geometrical shape).1.Colloids:The energy required to increase the surface area by a unit amount.().OR.The molecules at the surface have higher energy than those in the interior.Sol i

15、s highly dispersed and has a higher surface energy.It has a tendency to aggregate to decrease the surface energy.Therefore,sol is an unstable system.energy1.ColloidsThe dispersed phase is single(large)molecules,macromolecular solutions are stable systems.2.Macromolecular 1.ColloidsThe dispersed phas

16、e is molecular cluster.Associated colloids are stable systems.3.Associated colloid()Sodium stearate()2.SolMulti-phase;Highly-dispersed;Unstable.2.SolI.Properties of sol1.Optical properties():Tyndall effectThe scattering()of light by colloidal-size particles is known as the.A light beam is visible pe

17、rpendicular to its path only if light is scattered toward the viewer.Colloidsolution2.SolScattering of()laser beams by air molecules2.Sol2.Sol022212221423In2nnncV24IRayleigh formula:I0:Incident light intensity:Incident light wavelength V:particle volume c:concentration of particles n:refractive inde

18、x(折光指数折光指数)d Colloidsolution2.SolAlthough all gases and liquids scatter light,the scattering from a pure substance or true solution is quite small and usually not detectable.However,because of the considerable depth of the atmosphere,the scattering of light by air molecules can be seen.The blue colo

19、r of the sky is due to the fact that blue light is scattered more easily than red light.022212221423In2nnncV24IRayleigh formula:I0:Incident light intensity:Incident light wavelength V:particle volume c:concentration of particles n:refractive index两眼一眨不眨两眼一眨不眨勇敢的盯着太阳勇敢的盯着太阳直到太阳和我都变瞎直到太阳和我都变瞎天黑了地黑了太阳也

20、黑了天黑了地黑了太阳也黑了好久好久才醒过来好久好久才醒过来感觉到天地由黑转白感觉到天地由黑转白黎明从我这里向四面八方展开黎明从我这里向四面八方展开牛汉牛汉-童癖六首童癖六首（1923年10月2013年9月29日）Rayleigh scattering is more evident after sunset.This picture was taken about one hour after sunset at 500m altitude,looking at the horizon where the sun had set.早霞不出门，晚霞行千里早霞不出门，晚霞行千里2.Sol2.Dyn

21、amic properties()Brownian movement():The phenomenon that colloidal particles move irregularly and continuously in the medium.2.SolIt is resulted from the unbalanced collision from medium molecules.Decreasing sol particle size and viscosity()of medium,or increasing the temperature,favors Brownian mov

22、ement.Sol:dynamically stable system.2.Sol Diffusion and sedimentation equilibrium:Diffusion():The phenomenon that colloidal particles shift from a region with higher concentration to that with lower concentration.Reason:Brownian movement;Driving forces:concentration difference.2.SolSedimentation():T

23、he phenomenon that colloidal particles tend to sink due to gravitation.Sedimentation equilibrium:when diffusion and sedimentation are at equilibrium,a concentration gradient()occurs.It takes a very long time to reach this equilibrium,to accelerate this process Ultracentrifugation()2.Sol在密度均一的介质中由低速到

24、高速逐级离心，用于分离不同大小的细胞和细胞。在密度均一的介质中由低速到高速逐级离心，用于分离不同大小的细胞和细胞。differential centrifugation 差速离心差速离心 density gradient centrifugation 密度梯度离心密度梯度离心用一定的介质在离心管内形成一连续或不连续的密度梯度，将细胞混悬用一定的介质在离心管内形成一连续或不连续的密度梯度，将细胞混悬液或匀浆置于介质的顶部，通过重力或离心力场的作用使细胞分层、分液或匀浆置于介质的顶部，通过重力或离心力场的作用使细胞分层、分离。离。A等速度沉降等速度沉降，分离密度相近而大小不等的细胞或细胞器。B等密

25、度沉降等密度沉降,适用于分离密度不等的颗粒。2.Sol+-3.Electric properties Electrophoresis:+-NaCl solutionFe(OH)3sol+-NaCl solutionFe(OH)3sol2.SolElectrophoresis():directional movement of charged colloidal particles in an electric field.+-NaCl solutionFe(OH)3 solPositively-charged Fe(OH)3 colloidal particlesApplications:se

26、paration and identification of amino acids,polypeptides,proteins,and nucleic acids.2.SolInstrument for electrophoresis.Separation and identification proteins by electrophoresis.2.Sol2.SolElectroosmosis():directional movement of dispersed medium in an electric field.Reason:charging state of colloidal

27、 particles and medium.-colloidal particles fixed in a membrane+capillary()2.SolII.Structure of solAgNO3+KI +KNO3 KI in excess;AgIK+I-I-I-I-I-I-I-I-I-I-I-I-K+K+K+K+K+K+K+K+K+K+K+Colloidal particle()Colloidal nucleus()Sol1.Structure of sol2.SolAgImnI-(n-x)K+x-xK+Colloidal nucleusAdsorption layer Diffu

28、sion layerColloidal particleSolAgIK+I-I-I-I-I-I-I-I-I-I-I-I-K+K+K+K+K+K+K+K+K+K+K+Colloidal particle(胶粒胶粒胶粒胶粒)Colloidal nucleus(胶核胶核胶核胶核)SolAgIK+I-I-I-I-I-I-I-I-I-I-I-I-K+K+K+K+K+K+K+K+K+K+K+Colloidal particle(胶粒胶粒胶粒胶粒)Colloidal nucleus(胶核胶核胶核胶核)Sol2.Sol the thin layer composed of adsorbed ions on t

29、he colloidal nucleus surface and part of the confined counterions().the layer composed of the rest of counterions diffusing around the adsorption layer.the two-layer structure of oppositely-charged adsorption layer and diffusion layer.2.SolAgImnAg+(n-x)NO3-x+xNO3-Colloidal nucleusAdsorption layerDif

30、fusion layerColloidal particleSolAgNO3+KI AgI+KNO3 AgNO3 in excess;AgINO3-Ag+Colloidal particleColloidal nucleusSolAg+Ag+Ag+Ag+Ag+Ag+Ag+NO3-NO3-NO3-NO3-NO3-NO3-NO3-2.SolFe(OH)3mnFeO+(n-x)Cl-x+xCl-Colloidal nucleusAdsorption layerDiffusion layerColloidal particleSolFeCl3+3H2O Fe(OH)3+3HClFe(OH)3+HCl

31、FeOCl+2H2OFeOCl FeO+Cl-Fe(OH)3Cl-FeO+Colloidal particleColloidal nucleusSolFeO+FeO+FeO+FeO+FeO+FeO+FeO+Cl-Cl-Cl-Cl-Cl-Cl-Cl-2.Sol2.Electrically-charged colloidal particles1).Selective adsorption to the colloidal nucleus surface:Fe(OH)3 colloidal particles appear to be positively-charged due to selec

32、tive adsorption of FeO+.Fe(OH)3Cl-FeO+Colloidal particleColloidal nucleusSolFeO+FeO+FeO+FeO+FeO+FeO+FeO+Cl-Cl-Cl-Cl-Cl-Cl-Cl-2.SolAgIK+I-I-I-I-I-I-I-I-I-I-I-I-K+K+K+K+K+K+K+K+K+K+K+AgIK+I-I-I-I-I-I-I-I-I-I-I-I-K+K+K+K+K+K+K+K+K+K+K+AgNO3+KI AgI+KNO3AgINO3-Ag+Ag+Ag+Ag+Ag+Ag+Ag+Ag+NO3-NO3-NO3-NO3-NO3-

33、NO3-NO3-AgNO3 in excessKI in excess2.SolSilica sol colloidal particles appear to be negatively-charged.H2SiO3 HSiO3-+H+HSiO3-SiO32-+H+2).Dissociation of surface molecules around colloidal nucleus:Silica sol:Nucleus:xSiO2yH2OSurface:H2SiO32.SolAgIK+I-I-I-I-I-I-I-I-I-I-I-I-K+K+K+K+K+K+K+K+K+K+K+AgIK+I

34、-I-I-I-I-I-I-I-I-I-I-I-K+K+K+K+K+K+K+K+K+K+K+AgIK+I-I-I-I-I-I-I-I-I-I-I-I-K+K+K+K+K+K+K+K+K+K+K+AgIK+I-I-I-I-I-I-I-I-I-I-I-I-K+K+K+K+K+K+K+K+K+K+K+3).Effect of electrolyteelectrolyteelectrolyteelectrolyteAgI+I-I-I-I-I-I-I-I-I-I-I-I-K+K+K+K+K+K+K+K+K+K+AgII-I-I-I-I-I-I-I-I-I-I-I-K+K+K+K+K+K+K+K+K+K+K

35、+K+AgII-I-I-I-I-I-I-I-I-I-I-I-K+K+K+K+K+K+K+K+K+K+K+AgII-I-I-I-I-I-I-I-I-I-I-I-K+K+K+K+K+K+K+K+K+K+K+K+2.SolIII.Stability of sollElectrically-charged colloidal particles:Electrostatic repulsion among colloidal particles.lProtection of hydrated membrane()around colloidal particle:Elastic membrane.lBr

36、ownian movement.A colloid of gold particles(negatively-charged)in water prepared by Michael Faraday in 1857 is still preserved in the British Museum in London.Solutions of gold nanoparticles of various sizes.The size difference causes the difference in colors.2.Sol免疫金标记技术免疫金标记技术(Immunogold labelling

37、 techique)在金标蛋白结合处，在显微镜下可见在金标蛋白结合处，在显微镜下可见黑褐色黑褐色颗粒颗粒，当这些标记物在相应的配体处大量聚集时，肉眼可，当这些标记物在相应的配体处大量聚集时，肉眼可见红色或粉红色斑点，因而用于见红色或粉红色斑点，因而用于定性或半定量定性或半定量的快速的快速免疫检测方法中，这一反应也可以通过银颗粒的沉积免疫检测方法中，这一反应也可以通过银颗粒的沉积被放大，称之为被放大，称之为免疫金银染色免疫金银染色。纳米金纳米金即指金的微小颗粒，其直径在即指金的微小颗粒，其直径在1 1100nm100nm，具，具有有高电子密度高电子密度、介电特性介电特性和和催化催化作用，能与多种

38、生作用，能与多种生物大分子结合，且物大分子结合，且不影响其生物活性不影响其生物活性。2.Solaccumulations of gold particles over the neural granules 2.Sol2.SolIV.Coagulation of solCoagulation()is the process by which the dispersed phase(colloidal particles of sol)is made to aggregate and thereby separate from the dispersed medium(continuous ph

39、ase).An example is the coagulation of a colloidal suspension of soil in river water when the water meets the concentrated ionic solution of an ocean.The river delta()was formed in this way.Nile River delta,as seen from Earth orbit.The Nile is an example of a wave-dominated delta that has the classic

40、 Greek delta(,)shape after which river deltas were named.2.SolDeltas on Mars Finding deltas is a major sign that Mars once had a lot of water.2.Sol2.SolElectrolyte can push counterions to the adsorption layer and the charging state of colloidal particles.Two colloidal particles can approach close en

41、ough to aggregate.Critical coagulation concentration(CCC,):the minimum concentration of electrolyte needed to coagulate a certain amount of sol within a specified time.1.Effect of electrolyte AgIK+I-I-I-I-I-I-I-I-I-I-I-I-K+K+K+K+K+K+K+K+K+K+K+AgIK+I-I-I-I-I-I-I-I-I-I-I-I-K+K+K+K+K+K+K+K+K+K+K+electr

42、olyteAgII-I-I-I-I-I-I-I-I-I-I-I-K+K+K+K+K+K+K+K+K+K+K+AgII-I-I-I-I-I-I-I-I-I-I-I-K+K+K+K+K+K+K+K+K+K+K+K+AgIK+I-I-I-I-I-I-I-I-I-I-I-I-K+K+K+K+K+K+K+K+K+K+K+AgIK+I-I-I-I-I-I-I-I-I-I-I-I-K+K+K+K+K+K+K+K+K+K+K+2.SolCritical coagulation concentration(mmolL-1)AgI sol(-)Al2O3 sol(+)LiNO3 165 NaCl 43.5 NaN

43、O3 140 KCl 46 KNO3 136 KNO3 60 Ca(NO3)2 2.40 K2SO4 0.30 Mg(NO3)2 2.60 K2Cr2O7 0.63 Pb(NO3)2 2.43 K2C2O4 0.69 Al(NO3)3 0.067 K3Fe(CN)6 0.08 La(NO3)3 0.069 Ce(NO3)3 0.069 2.Sol0.14:1.8:100)31(:)21(:1c:c:c666MMM32A.The greater the magnitude of the charge of the counterion,the lower the CCC is.Shulze-Ha

44、rdy rule:B.Same magnitude of the charge of the counterion,coagulation capacity:For negatively-charged sol:H+Cs+Rb+NH4+K+Na+Li+For positively-charged sol:F-Cl-Br-I-CNS-2.Sol2.Coagulation of mixed sols with opposite electric charges Fe(OH)3Cl-FeO+FeO+FeO+FeO+FeO+FeO+FeO+FeO+Cl-Cl-Cl-Cl-Cl-Cl-Cl-AgIK+I

45、-I-I-I-I-I-I-I-I-I-I-I-K+K+K+K+K+K+K+K+K+K+K+AgIK+I-I-I-I-I-I-I-I-I-I-I-I-K+K+K+K+K+K+K+K+K+K+K+3.Macromolecular SolutionMacromolecule(polymer):a chemical species of very high molecular weight(10,000)made up from many units of low molecular weight linked together.Macromolecular solution is a kind of

46、 molecular solution.It is a homogeneous and stable system.However,the size of macromolecules falls into the range of colloidal dispersed system.Polymers are natural or synthetic(next slide).I.MacromoleculesMacromolecular solution solHeterogeneous systemHomogeneous systemStable systemsUnstable system

47、suncharged colloidal particlesCharged colloidal particlesViscosity,osmotic pressure Low viscosity and osmotic pressure solvation,Salting out Coagulation 3.Macromolecular SolutionFlexible-chain:good solvent3.Macromolecular Solution3.Macromolecular SolutionBranched polymer()Hyperbranched polymer()Dend

48、rimer()Linear polymer()Uniform structural unit:Polyethylene():(C2H4)nNatural rubber:(C5H8)nPolysaccharide():(C6H10O5)nNon-uniform structural unit:Protein():amino acidsNucleic acid():nucleotides()C CHHHHnC CHHHHnA polymer(聚合物聚合物)is a chemical species of very high molecular mass made up from many stru

49、ctural unit or monomer of low molecular mass covalently linked together.A compound used to make a polymer(and from which the polymers unit arises)is called a monomer(单体单体).3.Macromolecular Solution“团结就是力量团结就是力量”3.Macromolecular Solution“锁链化学锁链化学”Celluloid,discovered around 1868,was the first commerc

50、ial plastic.Initially it was used as a cheap substitute for ivory in making billiard balls.Cellulose(纤维)Cellulose nitrate(guncotton)is made by soaking a cellulose material such as cotton in a mixture of nitric and sulfuric acids.it catches fire and burns explosively.Table tennis ballscelluloid film3