Advanced Surface chemistry (2013, 2nd semester) Graduate course : # 458.622 (Core course) Credit : 3 Class hour: Tue. & Thr. 3:30 - 4:45 am Class room: 302-808 Lecturer: Prof. Jihwa Lee (Office Rm. 302-920, Tel: 880-7076) Textbooks Introduction to Colloid and Surface Chemistry 4th Ed: Duncan J. Show (John Wiley, 1994). Required. Principles of Colloid and Surface Chemistry 3th Ed: P.A.Hiemenz (Marcel Dekker, 1997) Recommended. Reference 1. Introduction to surface chemistry and catalysis: G.A.Somorjai (John Wiley, 1994) 2. Low Energy Electron and Surface Chemistry : G. Ertl & J Küppers ( VCH, 1985) 3. Physical Chemistry of Surfaces: A.W. Adamson (John Wiley, 1982) Grading Midterm and final exams ( 25 % each) 1 term paper and poster presentation (30 % each) Homework ( 20 % )

Topics to be covered Thermodynamics of surface Phenomena at curved surfaces Liquid-gas and liquid-liquid Interface 4. Adsorption and desorption 5. Surface reactions and heterogeneous catalysis Surface spectroscopy 7. Preparation of colloids 8. Kinetic properties of colloids 9. Optical properties of colloids 10. Charged interfaces & Electro-kinetic phenomena 11. Colloid stability

Ch.1 Thermodynamics of surfaces Surface thermodynamic quantities Surface tensions of liquids Intermolecular interactions Measurements of surface tension Surface tensions of solids

Surface thermodynamic quantities Molecules at surface vs. in the bulk Molecules (or atoms) at the surface are in a quite different chemical environment compared to those in the bulk in terms of intermolecular interactions. The surface molecules have less number of neighbors to interact with compared to those in the bulk. The interactions are attractive in liquids and solids. Therefore, the surface molecules are in a unstable state with a higher free energy. wire Extension of a soap film l f Extension of the film requires work w dG = dw = f dl → ΔG = f l soap film

Intermolecular interactions Interaction energy of Ar-Ar van der Waals (Dispersion force) V(r) = - A/r6 2. dipole-induced dipole dipole-dipole Hydrogen bonding Relative magnitude 1 < 2 < 3 < 4 Tb of gases (K) He Ar Xe NH3 H2O C10H8 4.2 87.3 165 230.7 373 491

E field by a static electric dipole

γ of various materials Tm(Pb) = 601 K, fcc metal Crystallographic orientation dependence of γ of Pb

FCC (Ar, Ni, Pd, Cu, Ag, Au)

Correlation between γ and ΔHsub T = Tm

Critical point Empirical equations proposed At T = Tc Not a liquid, not a vapor Condensation and vaporization occur rapidly. Local fluctuation of density No surface tension at T = Tc Empirical equations proposed γ = γ0 (T - Tc)n, where Tc is the critical T and γ0 is the surface tension at 0 K. n ~ 1 for metallic liquids and n> 1 for organic liquids. γ Vm2/3 = a (T–Tc) proposed by Eötvös, where a is a constant. γ (Vmx)2/3 = a (T–Tc – 6) by Ramsay and Shields, where x is the degree of association of the liquid (ex: x = 2 for acetic acid); most satisfaoctory