TY  - JOUR
AU  - Zinn, Thomas
AU  - Willner, Lutz
AU  - Lund, Reidar
AU  - Pipich, Vitaliy
AU  - Appavou, Marie-Sousai
AU  - Richter, Dieter
TI  - Surfactant or block copolymer micelles? Structural properties of a series of well-defined n-alkyl–PEO micelles in water studied by SANS
JO  - Soft matter
VL  - 10
IS  - 28
SN  - 1744-6848
CY  - Cambridge
PB  - Royal Society of Chemistry (RSC)
M1  - FZJ-2014-04535
SP  - 5212
PY  - 2014
AB  - Here we present an extensive small-angle neutron scattering (SANS) structural characterization of micelles formed by poly(ethylene oxide)-mono-n-alkyl ethers (Cn–PEOx) in dilute aqueous solution. Chemically, Cn–PEOx can be considered as a hybrid between a low-molecular weight surfactant and an amphiphilic block copolymer. The present system, prepared through anionic polymerization techniques, is better defined than other commercially available polymers and allows a very precise and systematic testing of the theoretical predictions from thermodynamical models. The equilibrium micellar properties were elaborated by systematically varying the n-alkyl chain length (n) at constant PEO molecular weight or increasing the soluble block size (x), respectively. The structure was reminiscent of typical spherical star-like micelles i.e. a constant core density profile, [similar]r0, and a diffuse corona density profile, [similar]r−4/3. Through a careful quantitative analysis of the scattering data, it is found that the aggregation number, Nagg initially rapidly decreases with increasing PEO length until it becomes independent at higher PEO molecular weight as expected for star-like micelles. On the other hand, the dependency on the n-alkyl length is significantly stronger than that expected from the theories for star-like block copolymer micelles, Nagg [similar] n2 similar to what is expected for surfactant micelles. Hence the observed aggregation behavior suggests that the Cn–PEOx micelles exhibit a behavior that can be considered as a hybrid between low-molecular weight surfactant micelles and diblock copolymer micelles.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000338644400019
DO  - DOI:10.1039/c4sm00625a
UR  - https://juser.fz-juelich.de/record/155366
ER  -