Self‐assembled, wormlike‐cylinder network of polystyrene‐block‐poly(ethylene oxide) micelles in solution

Abstract

ABSTRACT:We report the formation of a highly entangled and interconnected, selfassembled, wormlike-cylinder network of polystyrene-block-poly(ethylene oxide) in N, N-dimethylformamide/water. In this system, N,N-dimethylformamide was a common solvent and water was a selective solvent for the poly(ethylene oxide) blocks. The degrees of polymerization of the polystyrene and poly(ethylene oxide) blocks were 962 and 227, respectively. The network was formed at copolymer concentrations higher than 0.4 wt % and consisted of self-assembled, wormlike cylinders that were interconnected by Y-shaped, T-shaped, and multiple junctions. The network morphology was visualized with transmission electron microscopy. Capillary viscometry measurements revealed an order-of-magnitude increase in the inherent viscosity of the colloidal system upon the formation of the network. A similar effort to obtain a wormlike-cylinder network in an N,N-dimethylformamide/acetonitrile system, in which acetonitrile was a selective solvent for the poly(ethylene oxide) blocks, was unsuccessful even at high copolymer concentrations; instead, the wormlike cylinders showed a tendency to align. The viscosity measurements also did not show a substantial increase in the inherent viscosity. Thus, the solvent played a critical role in determining the formation of the self-assembled, wormlike-cylinder network. This formation of the network resulted from an interplay between the end-capping energy, bending energy (curvature), and configurational entropy of the self-assembled, wormlike-cylinder micelles that minimized the free energy.

Tuning solution polymer properties by binary water–ethanolsolvent mixtures

“…3C) revealed the presence of both cylindrical and spherical micelles, whereby the self-assembly of the pMeOx 40stat-PhOx 60 also resulted in the formation of merged cylinders, so-called Y-junctions. [25][26][27] The self-assembly of pMeOx 50 -stat-PhOx 50 in water with 20 wt.% ethanol (Fig. 3B) and pMeOx 30stat-PhOx 70 in water with 40 wt.% ethanol (Fig.…”

Fabrication of functional nano‐objects via self‐assembly of nanostructured hybrid materials

“…To create nonspherical nano‐objects, the self‐assembly of block copolymers in solution has been explored extensively3, 4 and a large diversity of morphologies has been discovered 5, 6. These include cylindrical micelles and various types of bicontinuous structures, for example, vesicles, as well as complex morphologies, such as networks of worm‐like aggregates and stacked‐ and cylindrical micelles having a structure‐in‐structure morphology 7–12…”

Morphology Control of Ni(II)-NTA-End-Functionalized Block Copolymer and Bio-Conjugation through Metal-Ligand Complex

“…When a predetermined concentration of water was reached, the solution was stirred for 30 min to equilibrate. To observe micelle morphologies retaining original shapes and sizes, a small amount of each sample was quenched after a particular interval with excess PBS for quick vitrification of p St block [ 45 ].…”