Ionic dye–surfactant nanoassemblies: interplay of electrostatics, hydrophobic effect, and π–π stacking

Molecular Insight into Dye–Surfactant Interaction at Premicellar Concentrations: A Combined Two-Photon Absorption and Molecular Dynamics Simulation Study

“…A previous study has revealed that electrostatic interactions between an anionic azo dye and a cationic CTAB surfactant, combined with hydrophobic effects and π–π interactions, play a major role in aggregate formation, the size of which depends on the surfactant alkyl group and the loading ratio of dye-to-surfactant concentration. It has also been observed that the stability of the aggregates enhances with the hydrophobic tail length of the surfactant . This argument could also hold good for the present cationic dye–anionic surfactant aggregates.…”

Self-Assembly and Dynamics Driven by Oligocarbonate–Fluorene End-Functionalized Poly(ethylene glycol) ABA Triblock Copolymers

“…Polymeric micelles self-assembled from amphiphilic block copolymers are employed in aqueous media as nanocarriers for hydrophobic drugs with high loading capacity and physical stability. − The hydrophobic core provides a reservoir for encapsulation of water-insoluble therapeutics, and the hydrophilic shell ensures dispersion in aqueous media. As new functional groups are incorporated, different micellar morphologies are observed due to the interplay of driving forces including electrostatic assembly, hydrogen bonding, π–π stacking interactions, − liquid crystalline packing, , and crystallization. , …”

Functional Nano-Objects by Electrostatic Self-Assembly: Structure, Switching, and Photocatalysis

“…The Gröhn group introduced a novel concept for forming electrostatically self-assembled nano-objects in solution by using “structural counterions” and presented a variety of supramolecular structures in solution formed by electrostatic self-assembly ( Gröhn, 2008 ; Li et al, 2009 ; Ruthard et al, 2009 ; Willerich et al, 2009 ; Gröhn, 2010 ; Gröhn et al, 2010 ; Kutz et al, 2016 ; Mariani et al, 2017a ; Frühbeißer and Gröhn, 2017 ; Frühbeißer et al, 2018 ). Similar to the material and the multilayer case, structures from various building block combinations can be created.…”

“… Shape variety in electrostatic self-assembly with different building blocks: (A) Wormlike bottle-brush polyelectrolytes and tetravalent porphyrin counterions form finite-size networks; AFM of brush and brush-porphyrin aggregates spin-coated on mica ( Ruthard et al, 2009 ); (B) POM–dendrimer assemblies; left: static light scattering and SANS of POM–dendrimer assemblies with l = 0.7; filled symbols: SLS data, open symbols: SANS data, black line at high q: flexible cylinder fit; right: TEM image ( Kutz et al, 2018 ); (C) Surfactant micelles connected by Ar26 ions as linkers; left: DLS, electric field autocorrelation function g 1 (τ) and distribution of relaxation times A(τ) for C 12 TAB-Ar26 assemblies; right: overview of structures formed: associated a) and individual spherical surfactant micelles b) with Ar26 molecules acting as connectors and condensed counterions, respectively, and cylindrical surfactant–dye aggregates from cylindrical surfactant micellization with condensed mutually π–π interacting Ar26 counterions c) ( Kutz et al, 2016 ). Reprinted with permission.…”

“…All these assemblies contain larger macroions; however, oppositely charged small molecules form assemblies in solution by combining several secondary interaction forces as well. Alkyltrimethylammonium surfactants and Ar26 build cylindrical particles of micelles with mutually π-π-stacked dye-counterions, as shown in Figure 8C : The charged surfactant and dye molecules interact by electrostatic interaction, the surfactants form micelles due to the hydrophobic effect and stacking due to π-π interactions between the dyes occurs ( Kutz et al, 2016 ). Thus, this system, on the one hand, represents an analogy to Faul’s dye-surfactant ionic self-assembly for material design and to the polyelectrolyte-dye nano-objects on the other hand.…”