We report a simple route to engineer ultrathin polymer brush surfaces with wrinkled morphologies using post-polymerization modification (PPM), where the length scale of the buckled features can be tuned from hundreds of nanometers to one micrometer using PPM reaction time. We show that partial crosslinking of the outer layer of the polymer brush under poor solvent conditions is critical to obtain wrinkled morphologies upon swelling. Characterization of the PPM kinetics and swelling behavior via ellipsometry and the through-thickness composition profile via time-of-flight secondary ion mass spectroscopy (ToF-SIMS) provided keys insight into parameters influencing the buckling behavior.
Conjugated polyelectrolytes (CPEs),
which combine a π-conjugated
polymer backbone with pendant ionic functionalities, offer an opportunity
for electrostatic control of materials properties. In this work, the
mesoscale morphology and physical properties of a high-mobility conjugated
polyelectrolyte are tuned by the addition of salt, variation of the
charge-compensating counterion, and complexation with an oppositely
charged polyelectrolyte containing the same π-conjugated backbone.
In systems with a single polyelectrolyte species, added ions screen
the electrostatic repulsions stabilizing the gel-phase, resulting
in the dissolution of ionic cross-links and hydrophobic collapse.
Exchanging the charge compensating counterion is found to enable finer
structural control of the solution behavior and modulation of the
self-doping behavior. Finally, novel CPE–CPE complexes resulting
in dense solutions and gels of semiconductive material are produced
by combination of oppositely charged polyelectrolytes. Such concentrated
CPE formulations should be useful materials for mixed electronic–ionic
conduction and pseudocapacitative energy storage.
Polymer brushes carrying pendent thiolactone functional groups were explored for the design of multifunctional homopolymer brush architectures using sequential and one-pot postpolymerization strategies.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.