Contents of Today S.J.T.U. Phase Transformation and Applications Page 1/42 Review previous Surface energy surface tension Effect of surface curvature Vapor pressure Solubility of small particles Wetting of surfaces Gibbs Adsorption Isotherm SJTU Thermodynamics of Materials Spring2008©X.J.Jin Lecture 20 surface
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2008 © X. J. Jin Lecture 20 surface Page 1/42 Contents of Today Review previous Surface energy / surface tension Effect of surface curvature Vapor pressure Solubility of small particles Wetting of surfaces Gibbs Adsorption Isotherm
Isolated System and Boltzmann Hypothesis S.J.T.U. Phase Transformation and Applications Page 2/42 Microcanonical ensemble An isolated system with N particals in a volume,V,with a fixed energy,E Premise:all microstates are equally probable Boltzmann hypothesis The entropy of a system is linearly related to the logarithm of S=kIn thermodynamic probability the number of different ways that macro-configuration can be achieved. N! Q= Entropy of mixing of two components N!Nu! Distribution of balls SJTU Thermodynamics of Materials Spring2008©X.J.Jimn Lecture 20 surface
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2008 © X. J. Jin Lecture 20 surface Page 2/42 Isolated System and Boltzmann Hypothesis Microcanonical ensemble An isolated system with N particals in a volume, V, with a fixed energy, E Premise: all microstates are equally probable Boltzmann hypothesis The entropy of a system is linearly related to the logarithm of Ω Ω：thermodynamic probability the number of different ways that macro-configuration can be achieved. !! ! ΠΙ =Ω NN N Entropy of mixing of two components = kS lnΩ Distribution of balls
ldeal Gas S.J.T.U. Phase Transformation and Applications Page 3/42 22--2 m小 In- =Nka) N kT RT P V V SJTU Thermodynamics of Materials Spring 2008 ©X.J.Jin Lecture 20 surface
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2008 © X. J. Jin Lecture 20 surface Page 3/42 Ideal Gas V h mkT L h mkT ZZZZ zyxxyz 2/3 2 3 2/3 2 2 2 ⎟⎠⎞ ⎜⎝⎛ ⎟ = ⎠⎞ ⎜⎝⎛ == π π T V F P ⎟⎠⎞ ⎜⎝⎛ ∂∂ −= ⎟⎟⎠⎞ ⎜⎜⎝⎛ −= +1ln A A NZ kTNF T A T A A V Z kTN V N Z kTN P ⎟⎠⎞ ⎜⎝⎛ ∂∂ = ⎟⎟⎟⎟⎟⎠⎞ ⎜⎜⎜⎜⎜⎝⎛ ∂ ⎥⎦⎤ ⎢⎣⎡ ⎟⎟⎠⎞ ⎜⎜⎝⎛ ∂ + = ln 1ln V RT V kTN P A ==
Today S.J.T.U. Phase Transformation and Applications Page 4/42 Surface energy surface tension Effect of surface curvature ·Vapor pressure Solubility of small particles ·Vetting of surfaces Gibbs absorption isotherm SJTU Thermodynamics of Materials Spring2008©X.J.Jin Lecture 20 surface
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2008 © X. J. Jin Lecture 20 surface Page 4/42 Today • Surface energy / surface tension • Effect of surface curvature • Vapor pressure • Solubility of small particles • Wetting of surfaces • Gibbs absorption isotherm
Introduction (1) S.J.T.U. Phase Transformation and Applications Page 5/42 Surfaces and Interfaces Everything is made of something and has to end somewhere. An atom at a free surface of a solid has greater energy than an atom in the interior of a crystal because it is less tightly bound. Surface energy The sum of all the excess energies of the surface atoms Can be defined in terms of energy,enthalpy, Helmholtz free energy,or Gibbs free energy, depending on the physical constraints placed on (a)由劈开晶体形成的自由键 the definition 本来应该担任配角”的界面比本当是主角”的构成相扮演更 重要的演出角色”！ SJTU Thermodynamics of Materials Spring 2008 X.J.Jin Lecture 20 surface
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2008 © X. J. Jin Lecture 20 surface Page 5/42 Introduction (1) Surfaces and Interfaces Everything is made of something and has to end somewhere. An atom at a free surface of a solid has greater energy than an atom in the interior of a crystal because it is less tightly bound. Surface energy The sum of all the excess energies of the surface atoms Can be defined in terms of energy, enthalpy, Helmholtz free energy, or Gibbs free energy, depending on the physical constraints placed on the definition 本来应该担任“配角”的界面比本当是“主角”的构成相扮演更 重要的“演出角色”！