CHIMICA FISICA DELLE SUPERFICI ED INTERFACCE

Knowledge and understanding ability: 

The objective is to enable the students, owing to the knowledge of phenomenology and theoretical model of surface thermodynamics and interatomic forces, to identify, recognize and analyse, qualitatively and quantitatively, the basic phenomena and processes occurring at surfaces and interfaces in condensed phase, as well as their dependence on the surfaciala and interfacial properties. A particular attention will be devoted to the phenomena and processes occurring at the fluid-fluid and solid-fluid interfaces.

Knowledge and applied understanding ability: 

The objective is to enable the students to apply the theoretical knowledge of surface and ointerface physical chemistry to phenomena and processes relevant for instance the nucleation and growth processes, the colloidal systems, the adhesion and adsorption processes of molecules and macromolecules, and, last but not least, the structuring of charged interfaces for energy.

Authonomy in evaluation:  

In order to promote the ability to autonomous evaluation of the suitability of the different methods of analysis to the above mentioned systems in view of their application to the innovative manufacturing, environmental technologies, renewable energetic and health fields, learning to critically consider the pertinence and the impact of the available technological option with respect to their efficiency and safety.   

Communication skills:

The learning of communication skills will be achieved both by performing sessions of presentation of tutorial topics, as well as presentations of small seminars, based on the construction of synthetic analysis of complex topics.

Learning ability

The learning capability will be specifically addressed by showing the way diverse theoretical aspects and the related phenomenological phenomena are connected and showing to the students the way of critically evaluate the generality and specific pertinence of the statements related to coherence and knowledge cogency.

Information for students with disabilities and/or DSA

To guarantee equal opportunities and in compliance with the laws in force, interested students can request a personal interview in order to plan any compensatory and/or dispensative measures, according to the teaching objectives and specific needs.

The course includes lectures in the classroom with exercises to better understand the practical application of the studied laws and models.

- Basics of electrostatics: Electrical fields and potentials, coulombian forces. relevant charge distributions.

- Basics of integral and differential calculus: field of existence of a function, derivatives, defined and undefined integrals, series ans series developments, simple first and secon order differential equations.

- Basics of solution colligative properties, pH, ionic force, etc...

- Properties of the thermodynamic potentials: Helmholtz and Gibbs fre energy, entropy, internal energy and basic thermodynamic relationships.

The students must attend at least 70% of the frontal classes, and in particular the ones dedicated to the intermolecular forces, the functionals of interface free energy and the related models of surface tension, the main surface properties, the properties of electrically charged surfaces, the wetting mechanisms, the adhesion of molecules at solid-liquid, solid-gas and liquid-gas interfaces.

Introduction to the Physical Chemistry of Interfaces and “soft” matter – Interfaces: definitions and properties – Gibbs and Guggenheim models – Properties-thickness relationships – Concept and operational definition of interfacial tension – nature and characteristic values of surface tension of fluids.

Curved liquid surfaces - Young-Laplace equation – Mixed curvature systems and capillarity constant – Further aspects of the Young-Laplace equation -  Kelvin equation – Case studies – Simple derivation of the Kelvin equation – Kelvin equation and critical stability dimensions – Elements for a nucleation theory – Energetics of the nucleation processes: liquid-vapour interfaces – Condensation processes and critical radius – Nucleation at solid-liquid interfaces: undercooling and solidification – Mechanisms of homogeneous nucleation and critical radius – Energy barrier for nucleation – Stability of solidification fronts: role of thermal fluctuation. 

Thermodynamics of surfaces and interfaces I – Thermodynamic energy functionals – Application of the thermodynamic functional to interfaces - Thermodynamicdefinition of surface work and surface tension – Helmholtz free energy of interfaces - Adsorption equation of Gibbs. 

Thermodynamics of surfaces and interfaces II - Surface tension and composition in miscible systems - Aqueous solutions – Surfactants: peculiar behavior and relationships among molecular structure and surface tension -  Gibbs monolayers and lateral pressure of films at surfaces – Techniques of lateral pressure measurement : Wilhelmy and Film balance methods – Correlations between molecular area and lateral pressure – Models of the “2D-ideal gas” and “2d real gas” – Adsorption of vapors at liquid surfaces. 

Thermodynamics of surfaces and interfaces III – “Independent Surface Action” principle - Molecular orientation and cohesive/adhesive work – Surface tension of homologous organic series in water -  Langmuir-Blodgett films: “Gas-like” and “liquid-like” states: state equations, phase transitions and Clausius-Clapeyron equation – Condensed state.

Thermodynamics of surfaces and interfaces IV - Spreading of liquids onto liquids: quasi-immiscible liquids - Spreading process energetics – Transient behaviours – Spreading of a liquid on solid surfaces: wettability – Mechanisms and energetics of wetting by spreading: Young equation and spreading pressure – Fowkes model: polar vs apolar contributions - Wetting by spreading, Wetting by adhesion and Wetting by immersion.

Intermolecular forces I - Forces and energies of intermolecular interaction - Interaction energy of molecules in spaces: couple potential model – Elementary form of the couple potential: rigid sphere model - Attractive and repulsive components - Interaction potentials in condensed phases: many body effects - Mean field potential and Self-energy definition – Cohesive energy for a simple liquid - Generalization of cohesive energy concept.

Intermolecular forces II - Boltzmann distribution of interaction energies  and definition of chemical potential – Molecular distribution in equilibrium systems - Thermal energy (KbT) as reference scale for intermolecular interactions – Boltzmann distribution and orientational states.

Intermolecular forces III - General classification of intermolecular forces - Functional form of relevant couple potentials - Electrostatic forces: Free energy of a coulombian bond - Definition of “self-energy” (or Born energy) of an ion - Nature of the “self-energy” – Partition processes of ions among phases with different dielectric constant – Ionic solubility in different solvents: continuous approximation – Ions of different dimension and dielectric constant.

Intermolecular forces IV – Quantum-mechanical forces - Dispersion interactions - London forces - Semiquantitative model. 

 Electrically charged solid-liquid interfaces – Classes of electrical potentials – Models of electrical double layer: continuum models –  Gouy-Chapman model – Planar surfaces: weak surface potentials and linearized Poisson-Boltzmann equation – Debye length and screening effects – Strong surface potentials and complete Poisson-Boltzmann equation - Discrete models of electrical double layers: simple and complex Stern models – Gibbs free energy of a Gouy-Chapmen double layer – notions of electro-kinetics potential. 

Colloidal dispersions – Definitions of colloidal dispersions- Stabilization factors: electrostatic effects, sterical effects “decoration” of surfaces with small or long molecules – Classes of colloidal systems and relative stabilities.

 
Biointerfaces - Surface free energy and biocompatibility – Other factors of biocompatibility: nanostructure effects – Anchoring of biomolecules and proteins at surfaces - Cell- surface interactions.

1 : Intermolecular and Surface Forces, di J.N. Israelachvili, Academic Press 1998 - cap.I-VI

2 : Physics and Chemistry of Interfaces, 3rd Edition Hans-Jürgen Butt, Karlheinz Graf, Michael Kappl; Wiley 2013 - Cap. I-IV

The examination will consist in an oral session concerning the topics treated during the lectures. Among the basic evaluation elements about the attainments of the candidates, a specific weight will be given to the correctness of their statements, the understanding of the conceptual basis of the discussed phenomena, the understanding of the derivation procedure of the basic equations and the correctness of scientific language. It will be considered as further expectable aspects of the validity of the candidate preparation the logic coherence when answering the examination questions and the capability to correlate theoretical notions and experimental aspects. 

Classes of intermolecular forces and shape of the related potentials

Surface free energy and related applications

Properties of the electrically charged interfaces

Gibbs monolayers 

Structure and properties of biointerfaces

Highly disperse systems 

Young equation and wetting of surfaces 

Adsorption from solutions at solid surfaces