Hierarchical Self‐Assembly of Amphiphilic Peptide Dendrons: Evolution of Diverse Chiral Nanostructures Through Hydrogel Formation Over a Wide pH Range

Abstract

An amphiphilic dendron containing three dendrite L-glutamic acid units and a long alkyl chain was synthesized by a convergent method. It was found that the dendron could form hydrogels over a wide pH range from 2 to 13. Moreover, accompanying the pH change, the compounds self-assembled into various chiral structures: from helical nanotube, helical nanotube with a string of beads, and coiled superhelix to dendrite nanostructures, such as pine, feather, etc. A series of characterizations based on TEM observations, X-ray diffraction and FTIR spectroscopic measurements revealed that the dendron formed a bilayer first and then hierarchically self-assembled into various chiral nanostructures. The four carboxylic acid groups and three amide groups played an important role in the self-assembly. The interaction between the multiamide groups stabilized the bilayer structures, whereas the ionization degree of the carboxylic acids was responsible for the formation of various chiral structures. The work presented a hydrogel system with wide pH adaptability and showed the regulation on chiral structures by simple pH variations.

Hierarchical Self-Assembly of Achiral Amino Acid Derivatives into Dendritic Chiral Nanotwists

“…Based on Bragg's equation, the layer distance or d spacing was estimated to be 4.12 nm for the nanofibers, indicating the formation of interdigitated bilayer structure. 56 The d spacing changed into 4.16 and 3.92 nm for the twists and the microbelts, respectively, suggesting that the bilayer structure was perturbed. The broad peak appeared for the twists might due to their discrete sizes.…”

Multiple‐Stimuli Responsive Luminescent Gels Based on Cholesterol Containing Benzothiadiazole Fluorophores

“…Compound 1a in gels state showed one sharp peak at 2θ of 1.84° (Figure 4), corresponding to d spacing of 4.81 nm, measured for the xerogels formed in dichloromethane. This distance of 1a indicates the molecules aggregate by linear type, [31,32] which could be due to π-π interactions and hydrogen bonding interactions. Especially, hydrogen bonding interactions make molecule linear between benzothiadiazole group and cholesterol.…”

Tuning Soft Nanostructures in Self‐assembled Supramolecular Gels: From Morphology Control to Morphology‐Dependent Functions

“…For example, the helical tube fabricated by a dendritic glutaimide lipid ( 3b ) had walls with a thickness of 4 nm, which corresponds to a bilayer thickness. [ 51 ] While many other compounds form multiwalled nanotubes, these dendron molecules formed double-walled nanotubes because the multi H-bond is stabilized by the bilayer structures. In fact, the nanotube formation for this dendron can tolerate a wide pH range.…”