Layer-by-layer self-assembly thin film based on carboxymethyl-β-cyclodextrins and diazoresin

Carboxymethyl-β-cyclodextrins (CM-β-CDs) having different carboxymethylated degrees were synthesized. Their structures and carboxymethylated degrees were characterized by H-NMR. A self-assembled multilayer thin-film was fabricated with CM-β-CD as an anion and photosensitive diazoresin (DR) as a polycation based on ionic interaction. The quantity of deposition of self-assembled CM-β-CD/DR films increased with increasing the degree of carboxymethylation of CM-β-CD and the ionic strength of solvent from which CM-β-CD deposited. However, the concentration and pH value of the CM-β-CD aqueous solution had little effect on the self-assembled multilayer films. Under UV irradiation, following the decomposition of diazonium group, between the adjacent interfaces of the multilayers, the ionic bonds of the self-assembly film converted to covalent bonds, which improves the stablity of the film effectively.