TY  - JOUR
AU  - König, Nico
AU  - Willner, Lutz
AU  - Pipich, Vitaliy
AU  - Zinn, Thomas
AU  - Lund, Reidar
TI  - Cooperativity during Melting and Molecular Exchange in Micelles with Crystalline Cores
JO  - Physical review letters
VL  - 122
IS  - 7
SN  - 1079-7114
CY  - College Park, Md.
PB  - APS
M1  - FZJ-2019-01640
SP  - 078001
PY  - 2019
AB  - Molecular exchange processes are important equilibration and transport mechanisms in both synthetic and biological self-assembled systems such as micelles, vesicles, and membranes. Still, these processes are not entirely understood, in particular the effect of crystallinity and the interplay between cooperative melting processes and chain exchange. Here we focus on a set of simple polymer micelles formed by binary mixtures of poly(ethylene oxide)-mono-n-alkyl-ethers (Cn−PEO5) which allows the melting point to be tuned over a wide range. We show that the melting transition is cooperative in the confined 4–5 nm micellar core, whereas the exchange process is widely decoupled and unimeric in nature. As confirmed by differential scanning calorimetry, the total activation energy for ejecting a molecule out of the micellar core below the melting point is the sum of the enthalpy of fusion and the corresponding activation energy in the melt state. This suggests that a “local, single-chain melting process” preludes the molecular diffusion out of the micelle during chain exchange.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000459311800010
DO  - DOI:10.1103/PhysRevLett.122.078001
UR  - https://juser.fz-juelich.de/record/861056
ER  -