Interfaces, Colloids and Self-Assembly

Code:

Q4062

Acronym:

Q4062

Keywords
Classification	Keyword
OFICIAL	Chemistry

Instance: 2017/2018 - 2S

Active?	Yes
Responsible unit:	Department of Chemistry and Biochemistry
Course/CS Responsible:	Master in Chemistry

Cycles of Study/Courses

Acronym	No. of Students	Study Plan	Curricular Years	Credits UCN	Credits ECTS	Contact hours	Total Time
M:Q	7	Official study plan until 2022/2023	1	-	6	56	162

Teaching language

English

Objectives

This course aims at familiarizing the students with the physico-chemical foundations of interfaces, colloidal systems and self-assembly phenomena, and their application in materials and processes used in everyday life and industry.

Learning outcomes and competences

By the end of the course the student should be able to:
- characterize the main physico-chemical features of the different types of interfaces;
- understand the different types of colloidal systems, their properties and structure-function relationships;
- understand the principles of the most important characterization methods for colloids and interfaces;
- develop experimental, presentation and communication skills on advanced topics of physical chemistry.

Working method

Presencial

Program

Module 1: Interfaces

1. Liquid-gas and liquid-liquid interfaces
1.1 Liquid interfaces and surfaces. Microscopic picture.
1.2 Molecular interactions and surface tension; mechanical definition of surface tension; surface tension and surface Gibbs energy. Interfacial tension: additivity of intermolecular forces at interfaces.
1.3 Young-Laplace equation.
1.4 Methods for measuring surface and interfacial tension in liquids; temperature dependence of the surface tension of liquids.
1.5 The Kelvin Equation: influence of curvature on vapor pressure of liquids.

2. Thermodynamics of interfaces
2.1 Gibbs surface energy, enthalpy and entropy and surface tension of pure liquids.
2.2 The surface excess; location of the interface; derivation of Gibbs adsorption isotherm.
2.3 Gibbs adsorption isotherm and its application to solutions of surfactants
2.4 Surfactants as stabilizers of liquid interfaces (emulsions) and surfaces (foams); Gibbs monolayers; Langmuir-Blodgett transfer.
2.5 Thick films.

3 Solid-gas and solid-liquid interfaces
3.1. Introduction. Thermodynamics of solid surfaces: surface tension and surface Gibbs energy.
3.2. Adsorption at solid surfaces and solid /liquid interfaces
3.3. Physical adsorption versus chemisorption; thermodynamics of adsorption: heats of adsorption: Adsorption and catalysis.
3.4. Classification of adsorption isotherms; presentation of adsorption isotherms.
3.5. Adsorption on solid/liquid interfaces: Langmuir and Freundlich isotherms
3.6. Surface modification

4. Contact angle phenomena and wetting
4.1 Young’s equation: contact angle and derivation
4.2 Spreading wetting; adhesional wetting; immersional wetting.
4.3. Measurement of the contact angle; hysteresis; contact angle and surface roughness and heterogeneity. Important wetting geometries
4.4. Thick films – spreading of one liquid on another.
4.5 Applications.

Module 2: Colloids and Self-Assembly

1. Colloidal systems: fundamental properties
1.1 Colloidal systems and interfaces: nature, size scale and interdependence.
1.2 Types of colloidal systems and soft materials - main characteristics. Colloidal dispersions, macromolecular solutions and association colloids; properties.
1.3 Structural characterization: particle shape, size and polydispersity.
1.4 Transport, electrical and optical properties.
1.5 Amphiphilic molecules and association colloids (self-assembled systems) – overview.

2. Self-assembled systems and nanostructures
2.1 Molecular and thermodynamic models for aggregation. Driving forces for self-assembly. Surfactant packing parameter and spontaneous curvature models.
2.2 Micelles: critical micelle concentration and Krafft point; thermodynamics of micellization; factors that influence the cmc; micellar shape, growth and solubilization.
2.3 Bilayer systems: composition, structure and dynamics; phase transitions. Vesicles or liposomes: structure and stability.
2.4 Liquid crystals, microemulsions and emulsions: structure and properties.
2.5 Phase behavior of surfactants and lipids: binary and ternary phase diagrams; characterization methods. Modification and control of self-assembly.

3. Macromolecules in solution
3.1 Introduction: structure of macromolecules and synthesis processes.
3.2 Average molecular weight of a polymer. Regimes of concentrations of polymer solutions.
3.3 Conformation of the polymer chain; defining factors.
3.4 Flory-Huggins theory: basic thermodynamic aspects. Polymer solubility and critical phenomena.
3.5 Behavior of macromolecules in solution and at surfaces; polyelectrolytes and block copolymers.
3.6 Mixed polymer-surfactant systems; models; critical aggregation concentration. Rheological aspects and applications

4. Colloidal interactions and stability
4.1 Intermolecular forces at the origin of colloidal forces.
4.2 Electrostatic interactions: electrical double layer model; zeta potential and its consequences; van der Waals interactions.
4.3 DLVO theory of colloidal stability; coagulation and flocculation.
4.4 Non-DLVO interactions.

5. Applications in nanotechnology, nanomedicine and industry
5.1 Chemistry-related and nanotechnology applications: detergency, emulsification, foaming; oil recovery; water treatment; food colloids; novel materials; thin films.
5.2 Biomedical and bio-related applications: drug delivery; non-viral gene therapy; biomaterials and biointerfaces.

Mandatory literature

Hiemenz Paul C.; Principles of colloid and surface chemistry. ISBN: 0-8247-7476-0
Shaw Duncan J.; Introduction to colloid and surface chemistry. ISBN: 0-408-71049-7
Evans D. Fennell; The colloidal domain. ISBN: 1-56081-525-6
Butt Hans-Jurgen; Physics and chemistry of interfaces. ISBN: 978-3-527-41216-7

Teaching methods and learning activities

The theoretical classes involve explanation of contents and interactive discussion with students. Practical classes comprise laboratory experiments with submission of lab reports.

The students will also develop a modern a topic on colloids and interfaces throughout the semester, during the practical classes, and will make oral presentations of this topic for the class. The aim of these presentations is to stimulate teamwork, autonomous work and communication skills.

Evaluation Type

Distributed evaluation with final exam

Assessment Components

designation	Weight (%)
Prova oral	30,00
Teste	40,00
Trabalho laboratorial	30,00
Total:	100,00

Amount of time allocated to each course unit

designation	Time (hours)
Apresentação/discussão de um trabalho científico	10,00
Estudo autónomo	76,00
Frequência das aulas	56,00
Trabalho laboratorial	20,00
Total:	162,00

Eligibility for exams

The students must attend a minimum of 3/4 of the number of the practical classes foreseen in the calendar.

Calculation formula of final grade

The final grade, FG, is calculated according to this formula:

FG = 0.40 x G(tests) + 0.30 x G(labs) + 0.30 x G(oral presentation)

G(tests) = 0.50 x G(Test 1- module1) + 0.50 x G(Test 2 – module 2)

To pass, the student must have: G(T1) ≥ 8, G(T1) ≥ 8, G(Tests) ≥ 10 and NF ≥ 10.