Cylindrical Micelles by the Self-Assembly of Crystalline-b-Coil Polyphosphazene-b-P2VP Block Copolymers. Stabilization of Gold Nanoparticles.

Maria De Los Angeles Cortes,Raquel De La Campa,Maria Luisa Valenzuela,Carlos Díaz,Gabino A Carriedo,Alejandro Presa Soto

doi:10.3390/molecules24091772

Maria De Los Angeles Cortes, Raquel De La Campa + Show 4 more

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https://doi.org/10.3390/molecules24091772

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Abstract

During the last number of years a variety of crystallization-driven self-assembly (CDSA) processes based on semicrystalline block copolymers have been developed to prepare a number of different nanomorphologies in solution (micelles). We herein present a convenient synthetic methodology combining: (i) The anionic polymerization of 2-vinylpyridine initiated by organolithium functionalized phosphane initiators; (ii) the cationic polymerization of iminophosphoranes initiated by –PR2Cl2; and (iii) a macromolecular nucleophilic substitution step, to prepare the novel block copolymers poly(bistrifluoroethoxy phosphazene)-b-poly(2-vinylpyridine) (PTFEP-b-P2VP), having semicrystalline PTFEP core forming blocks. The self-assembly of these materials in mixtures of THF (tetrahydrofuran) and 2-propanol (selective solvent to P2VP), lead to a variety of cylindrical micelles of different lengths depending on the amount of 2-propanol added. We demonstrated that the crystallization of the PTFEP at the core of the micelles is the main factor controlling the self-assembly processes. The presence of pyridinyl moieties at the corona of the micelles was exploited to stabilize gold nanoparticles (AuNPs).

Highlights

Block copolymers (BCPs) have received considerable attention due to their ability to self-assemble in both thin films or in selective solvent to one of the blocks, leading to a variety of different morphologies [1]
We describe that while searching for BCPs having semicrystalline PTFEP chains able to produce cylindrical micelles by self-assembly, we achieved the synthesis of the new polymer PTFEP-b-poly(2-vinylpyridine)
The novel poly(bistrifluoroethoxy phosphazene)-b-poly(2vinylpyridine) (PTFEP-b-P2VP) block copolymers 8a–c, having semicrystalline PTFEP core forming blocks, have been successfully synthesized copolymers 8a–c, having semicrystalline PTFEP core forming blocks, have been successfully by a method that proved to be of general applicability

Summary

Introduction

Block copolymers (BCPs) have received considerable attention due to their ability to self-assemble in both thin films (bulk) or in selective solvent to one of the blocks (solution), leading to a variety of different morphologies (e.g., spheres, rods, lamellae, etc.) [1]. By controlling the solubility properties, macromolecular architectures, molecular weights, and relative volume fractions of the constituent blocks [2,3,4,5,6], micelles of different morphologies such as toroids [7], vesicles [8], disks [9,10], ovals [11], helices [12,13], and other more complex structures have been created [14,15,16,17,18,19,20,21,22]. These cylindrical crew-cut micelles were not very stable in solution, needing of further core or corona cross-linking treatments in order to preserve their micelle architectures [28,29]

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