title: The effect of self-assembly conditions on the size of di- and tri-block copolymer micelles: solicitation from response surface methodology.
abstract: The objective of this study was to assess the application of Response Surface Methodology in defining the effect of self-assembly condition on the average diameter of polymeric micelles. Di- and tri-block copolymers of poly(ethylene oxide)-b-poly(α-benzylcarboxylate-ε-caprolactone) (PEO-PBCL) and PBCL-b-poly(ethylene glycol)-b-PBCL (PBCL-PEG-PBCL) were synthesized through ring opening polymerization of α-benzyl-ɛ-carboxylate using MePEO or dihydroxy PEG as initiator, respectively. Polymeric micelles were formed through solubilization of block copolymers in acetone followed by drop-wise addition of this solution to water. Polymer concentration was changed and the intensity mean diameter of self-assembled structures was measured by dynamic light scattering. The experimental data were fitted to a mathematical model. The experimental conditions leading to the production of micelles of certain size (30, 60 or 90 nm for tri-block and 30 nm for di-block copolymers) was predicted. A good match between predicted and experimental data was observed. The results showed it would be possible to obtain micelles of certain size using block copolymers of different molecular weights or obtain micelles of different size at a given block copolymer molecular weight, by manipulating the polymer concentration. These observations show reproducible micelles of defined average diameter can be prepared by co-solvent evaporation by controlling the used polymer concentration.
authors.affiliation: a Faculty of Pharmacy , Mazandaran University of Medical Sciences , Sari , Iran.|b Faculty of Pharmacy and Pharmaceutical Sciences , University of Alberta , Edmonton , Alberta , Canada , and.
authors.forename: Soheila
authors.initials: S
authors.lastname: Honary
authors.affiliation: b Faculty of Pharmacy and Pharmaceutical Sciences , University of Alberta , Edmonton , Alberta , Canada , and.|c Department of Chemical and Material Engineering , University of Alberta , Edmonton , Alberta , Canada.
authors.forename: Afsaneh
authors.initials: A
authors.lastname: Lavasanifar
keywords: Amphiphilic block copolymers; experimental design; micelle size; polymeric micelles; response surface methodology