Diblock copolymers of ethylene oxide and 1,2-butylene oxide in aqueous solution: formation of unimolecular micelles.
The dependence of log(cmc) on hydrophobic block length n was examined for E(m)B(n) copolymers (E=oxyethylene, B=oxybutylene, subscripts denote number-average block lengths in repeat units) with n in the range 30-76. Combination with published data for E(m)B(n) diblock copolymers with shorter E-blocks shows two changes of slope in the log(cmc)-n plot corresponding to the onset of unimolecular micelle formation at n approximately 12 and completion of this process at n approximately 30. The results are discussed with reference to published data for E(m)L(n) and E(m)CL(n) (L from d,L-lactide; CL from epsilon-caprolactone) copolymers, which show similar behaviour.
Ribeiro
Maria Elenir N P
ME
Department of Organic and Inorganic Chemistry, Polymer Laboratory, Federal University of Ceará, CX 12.200, CEP 60455-760 Fortaleza, Ceará, Brazil.
de Oliveira
Samira A
SA
Ricardo
Nágila M P S
NM
Mai
Shao-Min
SM
Attwood
David
D
Yeates
Stephen G
SG
Booth
Colin
C
D055598:Chemical Phenomena; D002626:Chemistry, Pharmaceutical; D002627:Chemistry, Physical; D004337:Drug Carriers / Q000737:chemistry*; D004852:Epoxy Compounds / Q000737:chemistry*; D008823:Micelles; D011092:Polyethylene Glycols / Q000737:chemistry*; D012995:Solubility; D012996:Solutions; D014867:Water
D004337:Drug Carriers; D004852:Epoxy Compounds; D008823:Micelles; D012996:Solutions; D014867:Water; C087757:poly(ethylene oxide)-poly(butylene oxide) copolymer; D011092:Polyethylene Glycols