A Comparative Study of Dynamic Light and X-ray Scatterings on Micelles of Topological Polymer Amphiphiles

Abstract

Micelles were prepared in organic solvents by using three topological polymer amphiphiles: (i) <i>cyclic</i> poly(<i>n</i>-decyl glycidyl ether-<i>block</i>-2-(2-(2-methoxyethoxy)ethoxy)ethyl glycidyl ether) (<i>c</i>-PDGE-<i>b</i>-PTEGGE) and (ii) its <i>linear</i> analogue (<i>l</i>-PDGE-<i>b</i>-PTEGGE); (iii) <i>linear</i> poly(6-phosphorylcholinehexylthiopropyl glycidyl ether-<i>block</i>-<i>n</i>-dodecanoyl glycidyl ether) (<i>l</i>-PPCGE-<i>b</i>-PDDGE). For the individual micelle solutions, the size and distribution were determined by dynamic light scattering (DLS) and synchrotron X-ray scattering analyses. The synchrotron X-ray scattering analysis further found that <i>c</i>-PDGE-<i>b</i>-PTEGGE forms oblate ellipsoidal micelle in an ethanol/water mixture, <i>l</i>-PDGE-<i>b</i>-PTEGGE makes prolate ellipsoidal micelle in an ethanol/water mixture, and <i>l</i>-PPCGE-<i>b</i>-PDDGE forms cylindrical micelle in chloroform. This comparative study found that there are large differences in the size and distribution results extracted by DLS and X-ray scattering analyses. All possible factors to cause such large differences are discussed. Moreover, a better use of the DLS instrument with keeping its merits is proposed.