Abstract
We present the synthesis and self‐assembly of a chiral bis(urea) amphiphile and show that chirality offers a remarkable level of control towards different morphologies. Upon self‐assembly in water, the molecular‐scale chiral information is translated to the mesoscopic level. Both enantiomers of the amphiphile self‐assemble into chiral twisted ribbons with opposite handedness, as supported by Cryo‐TEM and circular dichroism (CD) measurements. The system presents thermo‐responsive aggregation behavior and combined transmittance measurements, temperature‐dependent UV, CD, TEM, and micro‐differential scanning calorimetry (DSC) show that a ribbon‐to‐vesicles transition occurs upon heating. Remarkably, chirality allows easy control of morphology as the self‐assembly into distinct aggregates can be tuned by varying the enantiomeric excess of the amphiphile, giving access to flat sheets, helical ribbons, and twisted ribbons.
Highlights
Self-assembly is a very powerful bottom-up approach to build complex architectures,[1,2] taking advantage of information-rich building blocks that have specific supramolecular interactions.[3]
We show that these amphiphiles self-assemble into thermo-responsive chiral structures of which the morphology can be altered by heating or by simple mixing of enantiomers
The self-assembly behavior of these products was initially studied with circular dichroism (CD) spectroscopy (Figure 2)
Summary
Structures[10] to more complex architectures such as nanotubes,[11,12,13] sheets,[14] and ribbons.[15]. Among the number of motifs available for directing self-assembly, ureas have shown to effectively form stable soft materials. We envisioned that in order to tune morphologies, chirality can act as a powerful control element.[46,47,48,49,50,51,52] Tetraethylene glycol chains have been chosen as the hydrophilic component of the amphiphile to allow for good dispersion in water.[13,53,54,55] we decided to install aliphatic chains in proximity to the bis(urea) moieties to potentially trigger the formation of a hydrogen bonding network within the hydrophobic domain of the self-assembled structures. We show that these amphiphiles self-assemble into thermo-responsive chiral structures (nanoribbons) of which the morphology can be altered by heating or by simple mixing of enantiomers
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
