Interface Physics 1

Solid-liquid interfaces play an important role in many physico{chemical, biological and technical systems (e.g. energy conversion and storage, signal transduction in cells). The focus of this course lies on the structure and properties of the solid-liquid interface under equilibrium conditions. We will start with a discussion of solid electrodes and electrolytes, both seen as individual systems. The structure and electronic properties of metal and semiconductor electrodes will be discussed. In the case of electrolytes we will study the structure of liquids and electrolytic conductivity. It will be made clear which electronic states determine the reactivity of solid-liquid interfaces. Besides well established systems, such as aqueous solutions we will also have a look on novel electrolytes such as room temperature molten salts (ionic liquids). Then we will investigate what happens if these two systems are brought into contact: how can we describe the potential distribution across the newly formed interface, are there space charge layers and what are their characteristic length scales. Theories of the structure of the electric double layer will be treated and their application to real systems (e.g. electrochemical interfaces, colloids) will be discussed. - Introduction and review of important quantities and relations from electrostatics and phenomenological and statistical thermodynamics - Properties of solid electrodes; description of the structure of crystalline solids; surface lattices - Properties of metals; band models and Fermi energy; conductivity of metals - Properties of semi{conductors; electronic structure; conductivity of intrinsic and doped semi{conductors - Properties of electrolytes; structure of liquids; ionic conductivity of electrolytes; transference numbers - Formation of an solid{liquid interface; de nitions and essential fundamentals (Debye{ length, etc.); overview over some classical concepts (e.g. treatments of Helmholtz, Gouy{Chapman, Stern) - Thermodynamic treatment of phase boundaries; Gibbs adsorption isotherm; sur- face tension and surface energy - A classical example: the mercury{aqueous electrolyte interface; Lippmann&39;s ex- periments; electrocapillary curves - Charge and electrical potential at the metal{dilute electrolyte interface; electric double layer; solutions of the Poisson{Boltzmann equation for various boundary conditions - Charge and electrical potential at the semi{conductor{concentrated electrolyte in- terface - The Nernst equation; di erent types of electrodes - Energy levels in electrolytes (Gerischer&39;s approach) - Potential scales and di erent types of phase boundary potentials; membrane po- tentials - Electric double layers at nano{scaled systems; overlapping of electric double layers; colloid stability; DLVO theory

After participation in the module the student is able to: 1. Describe important properties (electronic, transport mechanisms) in solid and liquid phases 2. Explain the structure of solid{liquid interfaces (electrochemical double layers, space charge regions) under equilibrium conditions 3. Understand important terms such "electrochemical potential", "Nernst equation", "Debye length".

Keine Vorkenntnisse nötig, die über die Zulassungsvoraussetzungen zum Masterstudium hinausgehen.

lecture, beamer presentation, board work, exercises in individual and group work

practise sheets

1) H. Ibach: Physics of Surfaces and Interfaces, Springer, 2006 2) H.-J. Butt, K. Graf, M. Kappl: Physics and Chemistry of Interfaces, 2nd ed., Wiley-VCH, 2006 3) J. O&39;M Bockris, A. Reddy: Electrochemistry I. Ionics, 2nd ed., Plenum, 2000 4) J. O&39;M. Bockris, S.U.M. Khan: Surface electrochemistry, Plenum, 1993 5) R. J. Hunter: Foundations of Colloid Science, Oxford University Press,

In an oral exam the learning outcome is tested using comprehension questions and sample problems.

In accordance with §12 (8) APSO the exam can be done as a written test. In this case the time duration is 60 minutes.