Self-assembly of polystyrene-block-polybutadiene diblock copolymers in selective solvents and its crosslinking behavior upon γ-ray irradiation

Abstract

In our approach, using Delsa™ Nano submicron particle size dynamic light scattering analyzer, atomic force microscope, scanning electron microscope, and thermo-gravimetric analyzer, we investigated the self-assembly behavior of block copolymer polystyrene polybutadiene (PS-b-PB) in selective solvent, 2-butanone, as well as the effect of irradiation crosslinking that resulted in the immobilization of micelles. Since the selective solvent, 2-butanone, is the soluble solvent of PS segment and insoluble solvent of polybutadiene (Pb) segment, under suitable conditions, PS-b-PB could form monodisperse "core-shell" nano-micelles microstructure. The experimental results showed that under suitable conditions, PS-b-PB could form monodisperse nano-micelles with different core-shell components in selective solvent, and the size of micelles could be adjusted by controlling the mass fraction of PS-b-PB in the solvent. The micelle solution of 2-butanone/PS-b-PB block polymer system was further irradiated by γ-ray irradiation without oxygen, and the results showed that the micelles had a certain improvement in the micro-morphology and thermodynamic stability. The reason is that the crosslinking reaction of PB chain in the micelles induced by γ-ray irradiation is immobilized, and the cured micelles are no longer affected by ultrasonic vibration, solvent dilution, and volatilization. This study provided a new approach and method for the preparation of polymer nano-micelles.

Keywords

• polystyrene-block-polybutadiene (ps-b-pb)
• diblock copolymer
• self-assembly
• micelles
• γ-ray
• crosslinking behavior