1 research outputs found
Two Robust Strategies toward Hydrogels from Quenched Block Copolymer Nanofibrillar Micelles
While the formation of (tri)block
copolymer hydrogels has been
extensively investigated, such studies mostly focused on equilibrium
self-assembling whereas the use of preformed structures as building
blocks such as out of equilibrium, quenched, nanofibrillar micelles
is still a challenge. Here, we demonstrate that quenched, ultralong
polystyrene-<i>b</i>-poly(ethylene oxide) (PS-<i>b</i>-PEO) micelles can be used as robust precursors of hydrogels. Two
cross-linking strategies, (i) thermal fusion of micellar cores and
(ii) chemical cross-linking of preformed micellar coronas were studied.
The gelation process and the structure of the micellar networks were
investigated by in situ rheological measurements, confocal microscopy
and transmission electron microscopy. Direct observation of core fusion
of preformed quenched micelles is provided validating this method
as a robust gelation route. Using time sweep rheological experiments,
it was found for both cross-linking methods that these 3D “mikado”
gels are formed in three different stages, containing (1) initiation,
(2) transition (growth), and (3) stabilization regimes