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Title: Polydispersity-Driven Block Copolymer Amphiphile Self-Assembly into Prolate-Spheroid Micelles

The aqueous self-assembly behavior of polydisperse poly(ethylene oxide-b-1,4-butadiene-b-ethylene oxide) (OBO) macromolecular triblock amphiphiles is examined to discern the implications of continuous polydispersity in the hydrophobic block on the resulting aqueous micellar morphologies of otherwise monodisperse polymer surfactants. The chain length polydispersity and implicit composition polydispersity of these samples furnishes a distribution of preferred interfacial curvatures, resulting in dilute aqueous block copolymer dispersions exhibiting coexisting spherical and rod-like micelles with vesicles in a single sample with a O weight fraction, w{sub O}, of 0.18. At higher w{sub O} = 0.51-0.68, the peak in the interfacial curvature distribution shifts and we observe the formation of only American football-shaped micelles. We rationalize the formation of these anisotropically shaped aggregates based on the intrinsic distribution of preferred curvatures adopted by the polydisperse copolymer amphiphiles and on the relief of core block chain stretching by chain-length-dependent intramicellar segregation.
Authors:
; ;  [1]
  1. (UW)
Publication Date:
OSTI Identifier:
1034945
Resource Type:
Journal Article
Resource Relation:
Journal Name: ACS Macro Lett.; Journal Volume: 1; Journal Issue: 2012
Research Org:
Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
Sponsoring Org:
NSF
Country of Publication:
United States
Language:
ENGLISH
Subject:
36 MATERIALS SCIENCE; CHAINS; COPOLYMERS; DISTRIBUTION; POLYMERS; SEGREGATION; SURFACTANTS