Complex Formation of Sulfobetaine Surfactant and Ionic Polymers and Their Stimuli Responsivity

Abstract

We investigated the kinds of complexes sulfobetaine surfactant and ionic polymer formed using lauramidopropyl hydroxysultane (LAPHS) as a sulfobetaine surfactant, poly­(sodium styrenesulfonate) (PSSNa) as the anionic polymer and poly­[3-(methacrylamido)­propyl trimethylammonium chloride] (PMAPTAC) as the cationic polymer. The fundamental properties of LAPHS at various salt concentrations were estimated by various measurements, and it was confirmed that the LAPHS micelles alone did not show temperature responsiveness. The presence of large aggregates in addition to LAPHS micelles was confirmed in the aggregates prepared by adding PSSNa to LAPHS at a charge ratio of 1:0.5, 1:1, and 1:2. However, the aggregates could not be formed when the salt concentration was high or when a monomer was added instead of the polymer. This revealed that the cation part of sulfobetaine, which is the shell of LAPHS micelles, and the anion part of PSSNa electrostatically interacted with each other to form a large aggregate. On the other hand, unlike the case of LAPHS micelles alone and the aggregate consisting of LAPHS micelles and PSSNa, the aggregate of LAPHS micelles and PMAPTAC showed an unprecedented phenomenon of “clear → opaque → clear” with increasing concentration in the concentration range above CMC. The change in the transition temperature due to the change of concentration was a factor. Additionally, we confirmed that the transition temperature was lowered when the concentration was higher than CMC or the salt concentration was increased, and the transition temperature was increased when the PMAPTAC with a high degree of polymerization was added. These results suggested that the LAPHS micelles and the ionic polymer form an aggregate, and the temperature responsivity can be expressed by the interaction with the cationic polymer.

Developing Safe Organohydrogel Sunscreens Using Polyelectrolyte–Betaine Surfactant Complexes

“…Thus, the combined use of polyelectrolytes and surfactants can result in the formation of stable and functional structures with enhanced properties for various applications. Furthermore, stimulus-induced phase transitions in polyelectrolyte/surfactant complexes can lead to sol–gel transitions. − These transitions occur when the complexes undergo a change in their physical state, such as a change in temperature, pH, or ionic strength. The sol–gel transition is a reversible process, allowing for the formation of a stable gel network that can be used in various applications such as drug delivery, tissue engineering, and cosmetics.…”

Thermo-Responsive Polyion Complex of Polysulfobetaine and a Cationic Surfactant in Water

“…Despite the obvious interest in polymeric materials that respond to an environmental temperature [ 47 ], polymer/surfactant complexes, showing thermo-responsive behavior, have been scarcely explored [ 48 ]. For instance, Kim et al [ 49 ] reported the formation of a complex between the sulfobetaine surfactant lauramidopropyl hydroxysultane (LAPHS) and cationic poly((3-(methacryloylamino)propyl)trimethylammonium chloride) (PMAPTAC). The LAPHS surfactant has a quaternary amino cation and a pendant sulfonate anion in its structure; however, it exhibits a negative charge when dissolved in water.…”

Complex Formation in the Sulfobetaine-Containing Entirely Ionic Block Copolymer/Ionic Homopolymer System and Their Temperature Responsivity

“…Betaine polymers are divided into carboxybetaine (CB), phosphobetaine (PB), and sulfobetaine (SB) according to functional groups. , Among them, only sulfobetaine shows upper critical solution temperature (UCST) behavior in which the solubility increases rapidly when a certain temperature is exceeded. ,, The expression mechanism predicts that anions and cations form an intra- or intermolecular pair below the transition temperature and that the intra- or intermolecular pair is relaxed and dissolved by an increase in the kinetic energy of the molecular chain above the transition temperature. ,, Carboxybetaine is pH-responsive depending on the functional group. ,, Phosphobetaine has high biocompatibility and solubility due to its structural properties. , These have been studied in various fields such as brushes, ,, micelles, , organic–inorganic hybrid solar cells, − surfactants, − and gels. ,, …”