4. Self-assembled Nano structures of compound 1.
UV PSS : 64% trans % cis

5. Role of HB in aggregates
N-H stretching band (cm-1)
Amide-I band (cm-1)
Fibers (trans)
Spheres (cis)
Less than
Monomers

6. Grazing-incidence X-ray diffraction (GIXRD)
Self-assembly process:

7. Trans form:
Cis form:
Inter molecular HB induces assembly into planar sheet like structure.
zigzag configuration along the molecular axis with d-spacing of 42.8 A.
lamellar structure: van der Waals interaction + Pi-Pi stacking.
Retain zigzag configuration with reduced intermolecular spacing of 39.5 A.
(8 % reduction)
Steric hindrance between dialkoxy-phenyl gp twisting of the sheet like structure sphere

8. Solvent effect:

9. Conclusion:
A photoresponsive azobenzene-based compound possessing H-B groups showed
light- and solvent-triggered morphological transformations.
The cooperative effects of non-covalent interactions and partial E,Z isomerization was
sufficient to trigger the reversible transition of nanofibers into hollow spheres upon
UV-light irradiation.
The biuret units with photochromic azobenzene cores can be used as photosensitive
building blocks for the design of adaptive materials.