Surfactants and Block Copolymers:
Structure-Performance Relationships


Synopsis:

Surfactants find numerous applications in chemical process industries, in the formulation of pharmaceuticals, household products, and agricultural chemicals, in mineral processing technologies, and in food processing industries.  Naturally occurring surfactants in plants, animals, and humans have important biological or physiological functions.  The research activity in the field of surfactants has experienced enormous growth during the last twenty five years.  More than one thousand research articles are published annually and many scientific journals are devoted to the study of surfactants.

The wide-spread applications of surfactants originate from the intrinsic duality in their molecular characteristics, namely, they are composed of a polar head group that likes water and a non-polar tail group that dislikes water.  Numerous variations are possible in the types of the head groups and tail groups.   This variety in the molecular structure of the surfactants allows for extensive variation in their solution and interfacial properties.

One would naturally like to discover the link between the molecular structure of the surfactant and its self-assembling and solution properties so that surfactants can be synthesized or selected specifically for a given application.  This course is designed to address this need.

Who Should Attend:

This course is designed for industrial researchers and practitioners interested in surfactants, block copolymers and their applications. Depending on the interest of the audience, the topics and the extent of coverage can be varied from the description given below.

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Topics Covered:

Surfactants and Block Copolymers:
Structure-Performance Relationships

* INTRODUCTION TO SURFACTANTS

Classification of Surfactants
Introduction to Block Copolymers
Phenomenon of Self-Assembly
Critical Micelle Concentration
Aggregate Shapes
* PRINCIPLES OF SELF-ASSEMBLY Closed and Continuous Association
Pseudo-Phase Model
Estimation of Critical Micelle Concentration
Estimation of Micelle Size
Size Dispersion of Micelles
Concentration Dependence of Micelle Size
Micelle Charge
Concentration of Surfactant Monomer Beyond CMC
Sphere-to-Rod Transition
Sphere-to Bilayer Transition
* MOLECULAR PACKING AND SELF-ASSEMBLY Packing Requirements
Packing Parameter
Principle of Opposing Forces of Tanford
Packing Parameter Model
Predicting Type of Self-Assembly
* SURFACTANTS IN AQUEOUS SOLUTIONS Why Molecules Aggregate ?
What Factors Control Aggregate Size and Shape?
Determining Molecular Constants for Surfactants
Influence of Head Groups on Aggregation Behavior
Influence of Tail Groups on Aggregation Behavior
Influence of Ionic Strength on Aggregation Behavior
Influence of Temperature on Aggregation Behavior
Transition from Spherical to Rod-like Micelles
Formation of Vesicles
* SURFACTANT MIXTURES Ideal and Non-Ideal Mixed Micelles
Regular Solution Model
Size and Composition Distribution of Aggregates
How Surfactant Composition Affects Mixture Behavior ?
Nonionic Hydrocarbon-Nonionic Hydrocarbon Surfactant Mixtures
Ionic Hydrocarbon-Ionic Hydrocarbon Surfactant Mixtures
Ionic Hydrocarbon-Nonionic Hydrocarbon Surfactant Mixtures
Anionic Hydrocarbon-Cationic Hydrocarbon Surfactant Mixtures
Anionic Fluorocarbon-Nonionic Hydrocarbon Surfactant Mixtures
Anionic Hydrocarbon-Anionic Fluorocarbon Surfactant Mixtures
Origin of Ideal and Non-Ideal Mixing Behavior
* SURFACTANTS IN NON-POLAR SOLVENTS Differences Between Water and Non-Polar Solvents
Why Molecules Would Aggregate ?
Types of Aggregates
Size Distribution of Aggregates
Question of Existence of a CMC
Influence of Surfactant Molecular Structure
Influence of Temperature
Influence of Solvent Polarity
* SURFACTANTS IN POLAR ORGANIC SOLVENTS Types of Polar Solvents
Why Surfactants Would Aggregate ?
Shape and Size Distribution
Critical Micelle Concentration
Aggregate Size Polydispersity
Concentration-Dependent Aggregate Size
Micelle Formation in Mixed Aqueous-Organic Solvents
* SOLUBILIZATION Phenomenon of Solubilization
Relations for Solubilizate Uptake in Micelles
Why Solubilization Occurs and What Factors Limit it ?
Solubilization in Ionic Surfactant Solutions
Solubilization in Micelles of Poly(ethylene oxide) Surfactants
Solubilization-Induced Rod-to-Sphere Transition
Solubilization of Binary Hydrocarbon Mixtures
Solubilization in Mixed Micelles
* MICROEMULSIONS Microemulsion Formation
Droplet Microemulsions
Bicontinuous Microemulsions
Phase Diagrams
Size and Composition Dispersion of Droplets
Persistence Length in Bicontinuous Microemulsions
Calculation of Interfacial Tension
Phase Transitions Between Microemulsion Systems
Nonionic Microemulsions
Microemulsions With Ionic Surfactants
Use of Cosurfactants
* POLYMER-SURFACTANT INTERACTIONS Interaction of Nonionic Polymer with Globular Micelles
Interaction of Nonionic Polymer with Rod-like Micelles
Interaction of Nonionic Polymer with Vesicles and Bilayers
Interaction of Nonionic Polymer with Microemulsions
* BLOCK COPOLYMER AGGREGATES Structure of Block Copolymers
Aggregation of AB, ABA, BAB, and ABC Type Block Copolymers
Why Molecules Aggregate ?
What Factors Control Micelle Size ?
What Factors Determine Amount of Solubilization ?
Block Copolymer Composition and Aggregate Shapes
Solution Conditions and Aggregate Shape
Aggregate Shape Transitions Induced by Solubilization
Phase Behavior of Block Copolymer-Oil-Water System
Comparison to Conventional Surfactants
* SOME APPLICATIONS Chemical Separations
Selective Protein Extraction
Enzymatic Biocatalysis
Deinking of Laser and Xerox Printed Papers
Use as Environmentally-Benign Solvent for Product Recovery
Enhanced Oil Recovery
Lubricant Additives
Synthesis and Stabilization of Nanoparticles
* REVIEW AND CONCLUDING DISCUSSIONS
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Instructor

Professor Nagarajan is Professor of Chemical Engineering at the Pennsylvania State University.  He has pursued a research program focusing on the fundamentals of surfactant and block copolymer self-assembly over the past twenty five years.  He has formulated many of the predictive models available in the literature for a variety of self-assembly phenomena.  His research has also concentrated on the development of practical applications for self-assembled systems.  Past and current research projects include: enhanced oil recovery by surfactant/microemulsion flooding, chemical separations using emulsion liquid membranes, selective chemical extractions using aqueous micellar systems, preparation of stable concentrated liquid flavorings using
surfactant and block copolymer micelles,  aggregation of lubricant additives and additive interactions, separation of proteins and enzymes using microemulsions, enzymatic biocatalysis in block copolymer microdomains and in microemulsions, use of block copolymer surfactants for deinking and recycling of office waste paper, use of block copolymers for integrated fermentation and product recovery, and applications of surfactants in nanoparticle synthesis and processing.  He is a recipient of the Outstanding Research Award from the Pennsylvania State Engineering Society, US-France Foundation Fellowship for sabbatical research in Paris, France, and a CNRS Director of Research position during the period of sabbatical research in Toulouse, France.  He is on the editorial advisory board of Journal of Colloid and Interface Science.  He has been serving as the Program Chair of the American Chemical Society Division of Colloid and Surface Chemistry. He is currently working on a monograph "Surfactant Self-Assembly: A Predictive Molecular Thermodynamic Approach" which will provide much of the textual material for the short course.

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(C)  2002   Particles Conference