posted on 2021-09-23, 18:37authored byBabak Nouri, Chun-Yu Chen, Yu-Shan Huang, Bradley W. Mansel, Hsin-Lung Chen
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studies of the Frank–Kasper (FK) phase of block
copolymer (bcp) have highlighted the significance of the mass transfer
of constituent molecules in regulating the micelle size to fit in
the volume asymmetry of the Voronoi cells comprising the lattice.
Here, we present the transformation of a metastable liquidlike packing
(LLP) phase into the Laves C14 phase of a conformationally symmetric
bcp below the glass-transition temperature of the micelle core (Tgcore), where the mass transfer during the phase transition was prohibited.
The micelles composed of a hard core and a soft corona resembled fuzzy
colloids, with their ordering process occurred under the particle
number density and size distribution inherited from the LLP phase.
We argue that the relatively high size dispersity of the particles
drove the hard-core micelles to pack into the C14 phase to relieve
the packing frustration of the coronal blocks and the intermicellar
repulsion due to the large volume asymmetry and the small surface
area, respectively, of the Voronoi cells constituting C14 phase. The
present study identified a new regime in which FK phase could emerge
from the LLP phase with adequately high polydispersity of particle
size even for conformationally symmetric bcp and supported the significance
of the LLP structure in directing the ordered packing of bcp micelles.