Watching Molecular Nanotubes Self-Assemble in Real Time

Area of Science:

• Materials Science
• Biophysics
• Chemical Engineering

Background:

• Molecular self-assembly is vital for creating advanced materials in medicine and engineering.
• Understanding transient, short-lived stages in self-assembly remains a significant challenge.
• Double-walled molecular nanotubes serve as a model system due to their biological and synthetic relevance.

Purpose of the Study:

• To elucidate the real-time kinetics and intermediate structures during the self-assembly of double-walled molecular nanotubes.
• To investigate the formation and reorientation of transient structures in molecular self-assembly.
• To provide insights for controlling self-assembly processes for material engineering.

Main Methods:

• Utilized a benchmark system: double-walled molecular nanotubes with a selectively dissolved outer wall.
• Employed a combination of microfluidics and spectroscopy for real-time kinetic monitoring.
• Integrated cryogenic transmission electron microscopy (cryo-TEM) for structural analysis.
• Applied molecular dynamics simulations and exciton modeling for mechanistic insights.

Main Results:

• Observed that the outer wall self-assembles via a transient disordered patchwork intermediate.
• Identified the initial formation of multiple patches with varying orientations.
• Demonstrated that these patches interact and achieve global orientation over longer timescales.

Conclusions:

• The formation and reorientation of transient patch structures are key mechanistic steps in this self-assembly process.
• Understanding these intermediate stages is critical for guiding and controlling self-assembly.
• This knowledge advances the field of steered self-assembly for novel material design.