Amphiphilic Block Copolymers

Self-Assembly and Applications

P. Alexandridis, B. Lindman

• Publisher: Elsevier Science
• Year: 2000
• Print ISBN: 9780444824417
• eBook ISBN: 9780080527109
• Topic: Scienze fisiche
• Subtopic: Chimica fisica e teoretica

It is the belief of the editors of this book that the recognition of block copolymers as being amphiphilic molecules and sharing common features with other well-studied amphiphiles will prove beneficial to both the surfactant and the polymer communities. An aim of this book is to bridge the two communities and cross-fertilise the different fields. To this end, leading researchers in the field of amphiphilic block copolymer self-assembly, some having a background in surfactant chemistry, and others with polymer physics roots, have agreed to join forces and contribute to this book.The book consists of four entities. The first part discusses theoretical considerations behind the block copolymer self-assembly in solution and in the melt. The second part provides case studies of self-assembly in different classes of block copolymers (e.g., polyethers, polyelectrolytes) and in different environments (e.g., in water, in non-aqueous solvents, or in the absence of solvents). The third part presents experimental tools, ranging from static (e.g., small angle neutron scattering) to dynamic (e.g., rheology), which can prove valuable in the characterization of block copolymer self-assemblies. The fourth part offers a sampling of current applications of block copolymers in, e.g., formulations, pharmaceutics, and separations, applications which are based on the unique self-assembly properties of block copolymers.

Block copolymers of ethylene oxide and 1,2-butylene oxide

C. Booth; G.-E. Yu Manchester Polymer Centre, Department of Chemistry, University of Manchester, Manchester M 13 9PL, UK

V.M. Nace The Dow Chemical Company, Texas Operations, Research and Development, Freeport, Texas 77541, USA

Notation

E is used to denote an oxyethylene unit, OCH₂CH₂, and B to denote an oxybutylene unit, OCH₂CH(C₂H₅). For example, a diblock copolymer is denoted E_mB_n, and a triblock copolymer E_mB_nE_m or B_nE_mB_n. As a general notation for oxyethylene/oxybutylene copolymer systems we use E/B. In the same spirit, we use P to denote an oxypropylene unit, OCH₂CH(CH₃), and C to denote a methylene (or methyl) unit.

1 Introduction

The preparation of block copolymers of ethylene oxide and 1,2-butylene oxide was first disclosed by the Wyandotte Chemicals Corporation in 1955 [1]. Later patents followed from the Dow Chemical Company [2]. This early work, which has been well reviewed [3,4], provides information on the preparation and performance properties of E_mB_nE_m triblock copolymers. BASF-Wyandotte made E_mB_nE_m copolymers (denoted Butronics) available for research [5−7], but they were not commercialised, and no systematic study of their self-assembly has been published.

Starting in the early 1980s, Szymanowski and co-workers at Poznán described the performance properties of E/B copolymers covering the range of simple linear architectures: i.e. diblock (B_nE_m) and triblock (E_mB_nE_m and B_nE_mB_n). Preparative aspects are described in [8−10], and their many papers are reviewed in [11].

The preparation of E/B block copolymers and systematic study of their self-assembly in aqueous solution started in Manchester in the late 1980s, and continues to the present day [12−34]. At an early stage, cooperative work was undertaken with SUNY Stony Brook [16,23−26,29,31], and later with the Dow Chemical Company [26,27], the Surface Chemistry Institute, Stockholm [28], the Royal Institute of Technology, Stockholm [31], and the University of Bayreuth [32]. All the simple architectures (E_mB_n, B_nE_m, E_mB_nE_m, B_nE_mB_n, cyclo-B_nE_m) have been studied, and also tapered-block copolymers [28]. B_nE_mB_n copolymers have been a particular interest at Stony Brook [26,29,35]. A brief summary of much of this work has appeared in a recent review of the physical chemistry of poly(oxyalkylene) surfactants [36].

Diblock and triblock E/B copolymers were introduced as commercial products by the Dow Chemical Company in 1993, with a first description appearing in the commercial literature in 1992 [37]. Several reports of the properties of these copolymers have appeared ...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright page
• List of Contributors
• Preface
• Amphiphilic molecules: small and large
• Modelling of the self-assembly of block copolymers in selective solvent
• On the origin of the solution behaviour of ethyleneoxide containing polymers
• Block copolymers of ethylene oxide and 1,2-butylene oxide
• Self-Assembly of Block Polyelectrolytes
• Formation of Amphiphilic Block Copolymer Micelles in Nonaqueous Solution
• Structures of amphiphilic block copolymers in their liquid and solid states
• Structural Polymorphism of Amphiphilic Block Copolymers in Mixtures with Water and Oil: Comparison with Solvent-Free Block Copolymers and Surfactant Systems
• Small-Angle Scattering Studies of Block Copolymer Micelles, Micellar Mesophases and Networks
• Fluorescence studies of amphiphilic block copolymers in solution
• Direct-Imaging Cryo-Transmission Electron Microscopy in the Study of Colloids and Polymer Solutions
• Rheology Of Transient Networks Formed By The Association Of Hydrophobically Modified Water Soluble Polymers
• Applications of block copolymers
• Block copolymers in pharmaceutics
• Micelles of amphiphilic block copolymers as vehicles for drug delivery
• Applications of Amphiphilic Copolymers in Separations
• Polymeric Surfactants as Emulsion Stabilizers
• Subject Index