title: Morphological control of poly(ethylene glycol)-block-poly(epsilon-caprolactone) copolymer aggregates in aqueous solution.
abstract: In aqueous solution, it was found that the amphiphilic copolymer poly(ethylene glycol)-b-poly(caprolactone) (PEG(5000)-b-PCL(4100)) formed different morphologies, including long rod-like, short rod-like, or spherical aggregates, when the copolymer concentration was increased. Nearly identical morphologies were observed with the addition of increasing amounts of PEG(2000)-distearoylphosphoethanolamine (PEG(2000)-DSPE) to the copolymer. The morphologies of the aggregates in solution were confirmed by negative stain transmission electron microscopy (TEM) and cryogenic-TEM (cryo-TEM). The critical micelle concentrations of the PEG(5000)-b-PCL(4100) copolymer, PEG(2000)-DSPE and a mixture of the two materials (PEG(5000)-b-PCL 4100/PEG(2000)-DSPE) were evaluated to determine the thermodynamic stability of the aggregates. Differential scanning calorimetry was performed to gain insight into the degree of mixing of PEG(5000)-b-PCL(4100) and PEG(2000)-DSPE. Overall, combining PEG(5000)-b-PCL(4100) and PEG(2000)-DSPE produced a single population of mixed micelles with rod-like or spherical morphologies depending on the material composition and concentration.
authors.affiliation: Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, and Department of Chemistry, Faculty of Arts and Science, University of Toronto, 144 College Street, Toronto, Ontario, Canada.
authors.forename: Nichole
authors.initials: N
authors.lastname: Fairley
authors.forename: Bryan
authors.initials: B
authors.lastname: Hoang
authors.forename: Christine
authors.initials: C
authors.lastname: Allen
mesh_terms: D002152:Calorimetry, Differential Scanning; D005026:Ethylene Glycols / Q000138:chemical synthesis / Q000737:chemistry*; D008823:Micelles; D008970:Molecular Weight; D010316:Particle Size; D011091:Polyesters / Q000138:chemical synthesis / Q000737:chemistry*; D012996:Solutions; D013499:Surface Properties; D013696:Temperature; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D005026:Ethylene Glycols; D008823:Micelles; D011091:Polyesters; D012996:Solutions; C476300:poly(epsilon-caprolactone)-b-poly(ethylene glycol); D014867:Water