Abstract
In this paper, nanostructures formed in water by a novel series of (G)n(PO)68(G)n triblock copolymers, where n = 18−135, and G and PO stand for glycidol and propylene oxide, respectively, are parametrized. The copolymers are considered analogues of Pluronic copolymers in which the flanking poly(ethylene oxide) (PEO) blocks are substituted by polyglycidol (PG). PG is structurally similar to PEO and differs in that each monomer unit bears a hydroxymethylene group. In composition, the copolymers are closest to the Pluronic series L121−F127. Dilute (but invariably above the critical aggregation concentration) aqueous solutions in the temperature interval 25−70 °C were investigated by means of dynamic and static light scattering, cryogenic transmission electron microscopy, and small-angle neutron scattering (SANS). In the temperature-composition continuum studied the novel copolymers exhibit rich structural polymorphism. Large compound particles as those observed earlier for related copolymers, small core-corona micelles, rods, and vesicles were detected and parametrized by combining light scattering and SANS. Upon heating, the simultaneous increase in both hydrophobicity of poly(propylene oxide) and hydrophilicity of PG cause counteracting effects that are reflected in appearance of maxima in the temperature dependence of aggregation numbers of the particles, variations in the density of the latter, and anomalous thermotropic transitions for some of the copolymers.
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