Monolayers and Langmuir-Blodgett films of optically active macrocyclic poly(esters) containing the 1,1 '-bi-2-naphthol moiety at the air/water interface

In order to fabricate chiral Langmuir-Blodgett (LB) films and expand the ra nge of monolayer-forming materials, a new type of macrocyclic poly(aryl est er) containing the optically active 1,1'-bi-2-naphthol group, and which hav e no substituted alkyl chains, were investigated. The spreading behaviors a nd the fabrication of ultrathin films of the compounds were studied. Stable monolayers were formed with collapse surface pressures up to 40 mN m(-1) a t the air/water interface, although these compounds have no substituted alk yl chains. It is suggested that in the monolayers the macrocyclic rings lie flat on the surface of the water, while the aromatic rings extended upward s out of the water surface. The monolayers can be transferred onto solid su bstrates uniformly using the horizontal lifting method. Transferred LB film s were characterized by UV, polarized UV and circular dichroism (CD) spectr a. In comparison with the corresponding solutions, the B-1(b) and L-1(a) ba nds of the compounds in LB films show a red shift. Both the UV and polarize d UV spectra indicate a J-like aggregation of the chromophores in the LB fi lms. In the CD spectra, splitting of the Cotton effect is observed both in solution and in LB films, indicating that interactions between the neighbor ing naphthalene chromophores take place. In the LB films, the exciton coupl et shows a red shift in comparison with those in solution due to aggregatio n.