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Identifier

000282909

Title

Μικυλλιοποίηση σε μίγματα συμπολυμερών/ομοπολυμερών : επίδραση της αρχιτεκτονικής και της σύστασης

Alternative Title

Micellization in copolymer/homopolymer blends

Author

Καραγιάννη, Κωνσταντίνα Σωκράτη

Thesis advisor

Αναστασιάδης, Σπυρίδων

Abstract

Micellization in block copolymer/homopolymer blends is investigated via Dynamic Light Scattering and Rheology. The study is performed as a function of the block copolymer composition, architecture and its concentration in the homopolymer matrix. The effect of the total polymer concentration in a non-selective solvent is examined as well. Three (polyisoprene)2(polystyrene), I2S, graft copolymers with similar molecular weights but different compositions are utilized in matrix, PI, that is chemically identical to one of the copolymer blocks and the results are discussed in relation to the behavior of linear polyisoprene-polystyrene diblock copolymers, in polyisoprene, in solution and in the bulk. Micellization of the graft copolymer in the homopolymer matrix is observed for the sample with the highest PS number fraction (fPS=0.64) in all copolymer and total polymer concentrations. In contrast, the copolymer/homopolymer blend containing the graft copolymer that is poor in polystyrene (fPS= 0.09) indicates no micelle formation. Moreover, on the other hand, blends containing the graft copolymer with intermediate PS content (fPS=0.32) exhibit micelle formation depending on the polymer concentration in solution. The linear diblock copolymers, exhibit similar behavior with the respective graft ones. The copolymer/homopolymer blends containing the rich in polystyrene linear diblock copolymer show micelle formation in all concentrations, whereas the one with intermediate PS content contains micelles only in high polymer concentrations. However, the linear and graft copolymer systems differ on the size of the micelles that they form. Results from Rheology show no influence on the rheological response of the samples, independently of the presence or absence either of the copolymer chains or of the micelles. The results are discussed in relation to theoretical predictions and results from former works.

Language

Greek

Subject

Diblock copolymers

Dynamic Light Scattering

Graft copolymers

Micelles

Polymeric blends

Polymeric solutions

Rheology

Δυναμική Σκέδαση Φωτός

Δυσυσταδικά συμπολυμερή