Self-Assembly of Double Hydrophilic Poly(2-ethyl-2-oxazoline)-b-poly(N-vinylpyrrolidone) Block Copolymers in Aqueous Solution.

Jochen Willersinn,Bernhard V.K.J Schmidt

doi:10.3390/polym9070293

Jochen Willersinn, Bernhard V.K.J Schmidt

Open Access

https://doi.org/10.3390/polym9070293

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Journal: Polymers	Publication Date: Jul 20, 2017
Citations: 26	License type: CC BY 4.0

Affiliation: Max Planck Institute of Colloids and Interfaces

Abstract

The self-assembly of a novel combination of hydrophilic blocks in water is presented, namely poly(2-ethyl-2-oxazoline)-b-poly(N-vinylpyrrolidone) (PEtOx-b-PVP). The completely water-soluble double hydrophilic block copolymer (DHBC) is formed via copper-catalyzed polymer conjugation, whereas the molecular weight of the PVP is varied in order to study the effect of block ratio on the self-assembly process. Studies via dynamic light scattering, static light scattering as well as microscopy techniques, e.g., cryo scanning electron microscopy or laser scanning confocal microscopy, show the formation of spherical particles in an aqueous solution with sizes between 300 and 400 nm. Particles of the DHBCs are formed without the influence of external stimuli. Moreover, the efficiency of self-assembly formation relies significantly on the molar ratio of the utilized blocks. The nature of the formed structures relies further on the concentration, and indications of particular and vesicular structures are found.

Highlights

Block copolymer self-assembly is one of the most prominent fields in polymer science with plenty of applications such as lithography [1,2], drug-delivery [3,4], nano reactors [5] or compatibilization of polymer blends [6,7]
In were order formed to studyviathe self-assembly behavior of PEtOx-b-PVP
The synthesis of PEtOx-b-PVP was performed in two steps (Scheme 2)

Summary

Introduction

Block copolymer self-assembly is one of the most prominent fields in polymer science with plenty of applications such as lithography [1,2], drug-delivery [3,4], nano reactors [5] or compatibilization of polymer blends [6,7]. A frequently used way to form self-assembled structures in an aqueous solution is to change the solubility of one block via external stimuli, e.g., via temperature [16,17,18,19], pH [19,20,21] or redox [22,23]. In such a way, completely soluble block copolymers can be turned into an amphiphilic block copolymer, which results in the formation of self-assembled structures. Dynamic switches between colloidal states of polymer self-assemblies are possible as well as dissolution or formation of self-assembled structures

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Discussion

Conclusion