Morphology of hybrid polystyrene-block-poly(ethylene oxide) micelles: Analytical ultracentrifugation and SANS studies

6533b83afe1ef96bd12a79b2

RESEARCH PRODUCT

Morphology of hybrid polystyrene-block-poly(ethylene oxide) micelles: Analytical ultracentrifugation and SANS studies

L. V. Dubrovina F. Lo Celso Barry D. Stein G. I. Timofeeva Lyudmila M. Bronstein Roberto Triolo Robert L. Karlinsey A. Weidenmann Alexei R. Khokhlov Alexei R. Khokhlov Peter M. Valetsky Irina A. Khotina Dmitri M. Chernyshov Alessandro Triolo

subject

Models Molecular Block copolymer Hybrid micelles Micelle Polyethylene Glycols Biomaterials Surface-Active Agents chemistry.chemical_compound Colloid and Surface Chemistry Surfactant Polymer chemistry Copolymer Micelles Aqueous solution Calorimetry Differential Scanning Ethylene oxide Isotope effect Cationic polymerization Small-angle neutron scattering Surfaces Coatings and Films Electronic Optical and Magnetic Materials Microscopy Electron chemistry Polystyrenes Physical chemistry Polystyrene Pyridinium Ultracentrifugation

description

Abstract Morphology and structure of aqueous block copolymer solutions based on polystyrene- block -poly(ethylene oxide) (PS- b -PEO) of two different compositions, a cationic surfactant, cetyl pyridinium chloride (CPC), and either platinic acid (H 2 PtCl 6 ⋅6H 2 O) or Pt nanoparticles were studied using a combination of analytical ultracentrifugation (AUC), transmission electron microscopy (TEM), and small angle neutron scattering (SANS). These studies combining methods contributing supplemental and analogous structural information allowed us to comprehensively characterize the complex hybrid systems and to discover an isotope effect when H 2 O was replaced with D 2 O. In particular, TEM shows formation of both micelles and larger aggregates after incorporation of platinic acid, yet the amount of aggregates depends on the H 2 PtCl 6 ⋅6H 2 O concentration. AUC reveals the presence of micelles and micellar clusters in the PS- b -PEO block copolymers solution and even larger (supermicellar) aggregates in hybrids (with CPC). Conversely, SANS applied to D 2 O solutions of the similar species indicates that micelles are spherical and no other micellar species are found in block copolymer solutions. To reconcile the SANS and AUC data, we carried out AUC examination of the corresponding D 2 O block copolymer solutions. These measurements demonstrate a pronounced isotope effect on micelle aggregation and micelle size, i.e., no micelle aggregation in D 2 O solutions, revealing good agreement of AUC and SANS data.

year	journal	country	edition	language
2006-07-01	Journal of Colloid and Interface Science

https://doi.org/10.1016/j.jcis.2006.02.050