title: Study of complex thermosensitive amphiphilic polyoxazolines and their interaction with ionic surfactants. Are hydrophobic, thermosensitive, and hydrophilic moieties equally important?
abstract: The temperature-driven self-assembly of nonionic amphiphilic tailor-made triblock copolymers has been studied by DLS, NMR, ITC, and SAXS. The composition of these triblock copolymers is more complex than that of the vast majority of poly(2-alkyl-2-oxazoline)s: a statistical thermoresponsive (iPrOx) and hydrophobic (BuOx) central block with terminal hydrophilic blocks (MeOx). In general, as temperature increases, nanoparticles form in a process starting with single molecules that become loose aggregates and ends with the formation of compact nanoparticles. Here, we first attempt to resolve the effects of each block on nanoparticle formation. It has been proven that the iPrOx/MeOx ratio determines the value of the cloud point temperature, whereas the different BuOx-iPrOx blocks determine the character of the process. Finally, we complete our investigation by presenting the thermodynamic and structural profiles of the complexation between these triblock poly(2-alkyl-2-oxazoline)s and two ionic surfactants. The addition of an ionic surfactant promotes a rearrangement of the polymer molecules and the formation of complexes followed by the appearance of polymer-surfactant hybrid micelles. Analysis of the interaction shows a strong and nonspecific reaction between the polymers and the anionic surfactant sodium dodecyl sulfate and weak but polymer-state-sensitive interactions between the polymer and the cationic surfactant hexadecyltrimethylammonium bromide.
authors.affiliation: Institute of Macromolecular Chemistry AS CR, v.v.i, Heyrovsky Sq. 2, 162 06 Prague 6, Czech Republic.
authors.forename: Anna
authors.initials: A
authors.lastname: Bogomolova
authors.forename: Sergey K
authors.initials: SK
authors.lastname: Filippov
authors.forename: Larysa
authors.initials: L
authors.lastname: Starovoytova
authors.forename: Borislav
authors.initials: B
authors.lastname: Angelov
authors.forename: Petr
authors.initials: P
authors.lastname: Konarev
authors.forename: Ondrej
authors.initials: O
authors.lastname: Sedlacek
authors.forename: Martin
authors.initials: M
authors.lastname: Hruby
authors.forename: Petr
authors.initials: P
authors.lastname: Stepanek
mesh_terms: D000478:Alkylation; D057927:Hydrophobic and Hydrophilic Interactions; D007477:Ions / Q000737:chemistry; D008958:Models, Molecular; D010080:Oxazoles / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*; D013696:Temperature
chemical_list: D007477:Ions; D010080:Oxazoles; D011108:Polymers; D013501:Surface-Active Agents