Novel self-assembling system based on resorcinarene and cationic surfactant

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Physical Chemistry

Background:

• Calix[4]resorcinarene (CR) derivatives and cationic surfactants are key components in self-assembly studies.
• Understanding the mixed aggregation behavior of these molecules is crucial for developing advanced materials.
• The interplay between electrostatic and hydrophobic forces dictates aggregate formation and properties.

Purpose of the Study:

• To investigate the mixed aggregation of calix[4]resorcinarene (CR) with ethyl sulfonate and dimethylaminomethyl groups and a cationic surfactant (4-aza-1-hexadecyl-azoniabicyclo[2.2.2]octane bromide, DABCO-16).
• To determine the influence of concentration on aggregate composition and structure.
• To evaluate the binding capacity of the formed aggregates for hydrophobic probes.

Main Methods:

• Tensiometry
• Conductometry
• Potentiometry
• NMR spectroscopy
• Spectrophotometry for dye solubilization

Main Results:

• Mixed aggregates form, initially enriched by CR via electrostatic forces (around 0.4 mM DABCO-16).
• At higher concentrations (around 5 mM DABCO-16), aggregates become enriched by the surfactant due to hydrophobic effects.
• Only surfactant-enriched aggregates effectively bind the hydrophobic dye Orange OT, indicating selective binding capabilities.

Conclusions:

• The study elucidates the concentration-dependent formation of distinct mixed aggregates between CR and DABCO-16.
• The surfactant-enriched aggregates exhibit selective binding of hydrophobic molecules.
• These findings offer a basis for designing nanocontainers with tunable binding and release functionalities.