1998 E.W.R. Steacie Award Lecture Asymmetric amphiphilic block copolymers in solution: a morphological wonderland
- 1 August 1999
- journal article
- Published by Canadian Science Publishing in Canadian Journal of Chemistry
- Vol. 77 (8), 1311-1326
- https://doi.org/10.1139/v99-141
Abstract
Asymmetric amphiphilic diblock copolymers self-assemble in selective solvents. Since 1995, when we first reported the systematic preparation of a sequence of various "crew-cut" aggregate morphologies from this class of copolymer in solution (1), we have identified a vast array of structures and have begun a detailed investigation of the thermodynamic and kinetic parameters that induce morphogenesis. Not only spheres, rods, bilayer and bicontinuous architectures, as well as inverted structures are observed, but also a selection of mixed, combined and much more complex aggregates is documented. All of these aggregates have a phase-separated insoluble core and a crew-cut soluble corona. Thus, all parameters that permit selective modification of the component of either phase or of the interface provide a window for morphological control. By carefully adjusting the polymer chain environment, it has been possible to develop a systematic understanding of morphogenic parameters, which include, among others, polymer composition, common solvent, initial concentration, temperature, type and concentration of added ions, method of preparation, and added homopolymer. To date, more than 30 publications have appeared in the literature from our group alone on this subject. One of the problems inherent with such a complicated system is the taxonomy or classification: which morphologies correspond to equilibrium positions and which are intermediate or trapped? An attempt at a logical presentation of the observed aggregates is given, preceded by a qualitative discussion of the thermodynamic framework for this system. Where possible, the transitions between morphologies are explained in the context of the thermodynamic parameters. Finally, parallels are drawn between the copolymer aggregates and biological architectures.Key words: crew-cut, morphology, block copolymer, self-assembly, amphiphile.Keywords
This publication has 52 references indexed in Scilit:
- Morphogenic Effect of Solvent on Crew-Cut Aggregates of Apmphiphilic Diblock CopolymersMacromolecules, 1998
- Hairy, Semi-shaved, and Fully Shaved Hollow Nanospheres from Polyisoprene-block-poly(2-cinnamoylethyl methacrylate)Chemistry of Materials, 1998
- Multiple Morphologies of Crew-Cut Aggregates of Polybutadiene-b-poly(acrylic acid) Diblocks with Low Tg CoresLangmuir, 1997
- Novel Morphologies of “Crew-Cut” Aggregates of Amphiphilic Diblock Copolymers in Dilute SolutionLangmuir, 1996
- Ion-Stabilized Block Copolymer Micelles: Film Formation and Intermicellar InteractionMacromolecules, 1996
- Micelles Formed by a Model Hydrogen-Bonding Block CopolymerMacromolecules, 1995
- Micellization of an asymmetric block copolymer in mixed selective solventsPolymer, 1994
- Surface micelle formation at the air/water interface from nonionic diblock copolymersLangmuir, 1993
- Hybridization of block copolymer micellesLangmuir, 1993
- Anomalous micellization behavior and composition heterogeneity of a triblock ABA copolymer of (A) ethylene oxide and (B) propylene oxide in aqueous solutionMacromolecules, 1988