Introductory description

Colloid science provides fundamental and essential enrichment of polymer science. The area experiences marked interest from the chemical industries across a great variety of application areas, such as laundry and personal care products, drug delivery formulations, food and drinks, coatings and adhesives, agricultural formulations and many others.

Module web page

Module aims

Outline syllabus

This is an indicative module outline only to give an indication of the sort of topics that may be covered. Actual sessions held may differ.

The module is divided into 5 key learning blocks.

BLOCK 1: ON (MINI)EMULSION POLYMERIZATION
In this block we will discuss:

1. Introduction to colloids: what is a colloid? Phases and colloidal systems. Specific properties. Ancient colloids. The importance of surface area. Capillarity. Laplace pressure. Variety of shapes. Lyophilic vs. lyophobic colloids.
2. Emulsion polymerization: what is an emulsion polymerization and how does it differ from a suspension polymerization, dispersion polymerization, precipitation polymerization, and miniemulsion polymerization? A brief history of emulsion polymerization. Pro’s and con’s of emulsion polymerization vs. bulk/solution polymerization. A typical recipe.
3. Mechanistic understanding of Emulsion Polymerization: rate of polymerization, particle formation (micellar and homogeneous nucleation), particle growth, particle swelling, diffusion limitation/starved conditions, compartmentalization, zero-one vs. pseudo bulk polymerization kinetics, Trommsdorf effect.
4. Miniemulsion polymerization: What is miniemulsion polymerization? Ostwald ripening, how to retard/arrest Ostwald ripening.

BLOCK 2: ON MOTION AND COLLOID STABILITY

In this block we will discuss
Motion of colloids: gravity, buoyancy, drag force (Newton/Rayleigh/Stokes), terminal velocity, Brownian motion, Osmotic pressure, Stokes Einstein (Smoluchowski/Langevin), Barometric height, Ballistic velocity, Propulsion on the microscale (Purcell)
Colloidal stability: How to prolong the lifetime of a lyophobic colloid. Electrostatic stabilization. DLVO theory. Steric stabilization. Bridging and depletion flocculation. Kinetics of coagulation.

BLOCK 3: COLLOID STABILITY
After recapping ways to stabilize colloids via electrostatic, steric, or depletion methods, we will look in detail into the DLVO theory. Key words: charged interfaces, van der Waals interactions, Hamaker coefficient, Derjaguin approximation, Coulomb repulsion, double layer, critical coagulation concentration.

BLOCK 4: WETTING AND PARTICLES AT SOFT INTERFACES
We will introduce scientific principles of capillarity. In this context we will focus and explore the phenomenon of Pickering stabilization, in that solid particles have the ability to adhere to a soft (i.e. liquid-liquid or liquid-gas) interface. Key-words: Pickering emulsions, Ore flotation, capillary forces, wetting/de-wetting, interfacial and line tension, contact angle.

BLOCK 5: RHEOLOGY
We will (re-) introduce rheological concepts and apply these to colloidal dispersions. Key words: kinematics and dynamics, shear rate, stress, viscosity. Yield stress, visco-elasticity, shear thinning and thickening. Hydrodynamic effects. Brownian contributions. Flocculation and thixotropy (Reversible time effects).

Learning outcomes

By the end of the module, students should be able to:

• KNOWLEDGE: The module will provide students with a solid understanding of several fundamental and contemporary aspects of colloid science focussing on five key learning blocks (fundamentals (blocks 1-2), particles at soft interfaces, colloid stability, and rheology: see point 20 for more detail). Students will develop specialized knowledge in the area of colloid science and integrate this across the wider areas of chemistry, chemical engineering, physics and manufacturing.
• DIVERSE PERSPECTIVES: Through interactive workshops and a group project students will be able to evaluate diverse points of view embedded within varying frameworks which may include, technological/scientific context, societal and environmental impact, temporal and trending contexts.
• COMPETENCY SKILLS: Students will engage in critical inquiry and develop their skill set to process, understand, and communicate/explain and evaluate scientific principles and their impact.
• APPLIED LEARNING: This module has a designed set of workshops associated with each block of learning in which concepts will be applied and integrated in an interactive discussion format.
• COMMUNICATION: Student will be able to communicate effectively in presenting ideas orally (especially in the workshop sessions), and in the format of an assessed group presentation
• ETHICAL REASONING: Students will be able to reason ethically in evaluating the design and use of colloidal materials in nowadays society and illustrate their learning in the form of a group project/presentation.

Indicative reading list

Colloid Science: Principles , Methods and Applications by Terence Cosgrove, 2nd ed. WileyBlackwell (2010) ISBN-10:1444320203 ISBN-13: 987-1444320206
Principles of Colloid and Surface Chemistry, Paul C. Hiemenz and Raj Rajagopalan, 3rd Ed. CRC Press (1997) ISBN-10: 0824793978 ISBN-13: 987-0824793975
Polymer Colloids by Robert M. Fitch, Academic Press (1997), ISBN-10: 0122577450 ISBN-13: 987-0122577451
Capillarity and Wetting Phenomena: Drops, Bubbles, Pearls, Waves by Pierre-Gilles de Gennes, Francoise Brochard-Wyart, and David Quere, Springer (2003) ISBN-10: 0387005927 ISBN-13: 987-0387005928

Subject specific skills

Understanding of what is a colloid
Understanding Ostwald ripening and its importance to nanodroplets and particles. Capillary forces with respect to adhesion, wetting and dewetting. Particles at soft interfaces.
Fabrication of emulsions, inorganic nanoparticles, polymer colloids. Control of size, morphology. Synthetic aspects. Basic understanding of mechanism of particle formation and growth. How to make anisoptropic particles.
Understanding the basics of colloidal stability, particle size distribution characterization, rheology, and particle assembly
Understand how to control the chemical composition of particles and particle morphology in emulsion polymerization, microgels, nanogels and anisotropic colloids
Understand research topics in the area of emulsions, colloids and assembly.

Transferable skills

Presentation delivery