Aggregation and Rheology of a Triblock Supra-amphiphilic
Polymer Prepared by Ionic Self-Assembly of a Double-Hydrophilic Polyelectrolyte
with an Oppositely Charged Surfactant in Aqueous Solution
posted on 2021-05-28, 14:36authored byXi Chen, Zhukang Du, Yan Hu, Ning Sun, Biye Ren
Supra-amphiphilic
polymers as a kind of interesting and important
supra-molecules have received considerable attention due to their
unique advantages in preparation and promising applications in many
areas. This work reported the solution aggregation and viscoelastic
behavior of a triblock supra-amphiphilic polymer, which was fabricated
by the ionic self-assembly of a triblock double-hydrophilic polyelectrolyte,
poly(3-sulfopropylmethacrylate potassium salt)-b-poly(ethylene
glycol)-b-poly(3-sulfopropylmethacrylate potassium
salt) (PKSPMA-b-PEG-b-PKSPMA), with
a cationic surfactant, dodecylamine hydrochloride (DAHC). The resulting
supra-amphiphilic polymer contains a hydrophilic PEG middle block
and two noncovalently linked hydrophobic end blocks, which are analogous
to ABA-type triblock associative polymers (TAPs). Such a triblock
supra-amphiphilic polymer has similar aggregation and rheological
behavior to typical TAPs in aqueous solution. It can self-assemble
into micelles and/or micellar aggregates in dilute solution and even
form a clear physical gel in the concentrated solution by the bridging
of polymer chains. However, it still exhibits some distinct rheological
features from typical TAPs. Some factors such as the binding stoichiometry
of oppositely charged groups and salt concentration have significant
influence on its solution rheological properties. The solution relaxation
dynamics follow the time–concentration/salt superposition and
are dominantly controlled by the electrostatic interactions in the
form of ion–ion pairs rather than the hydrophobic association
in the core of a micelle. This work is the first time to report the
solution rheological behavior of a supra-amphiphilic associative polymer.
This result provides a new approach not only to the understanding
of the solution rheology of the supra-amphiphilic associative polymers
but also to the construction of a supramolecular viscoelastic gel.