Langmuir and Langmuir-Blodgett films of a homopolymer of Disperse Red-13

We report on the formation of stable and uniformly transferable Langmuir monolayers of a methacrylic homopolymer of Disperse Red-13 (HPDR13). There was no need of covalently attaching long alkyl side chains or mixing the homopolymer with film forming materials. HPDR13 was derived from DR13-methacrylate by a homo polymerization reaction in the presence of 2,2'-azobisisobutyronitrile as initiator. Surface pressure isotherms were obtained under various subphase temperatures, pH conditions and at several compression speeds. The monolayer has also been characterized by surface potential isotherms. The results indicated that, in contrast to the poor stability of a methacrylate-DR13 monomer monolayer, stable monolayers of HPDR13 could be obtained at the air-water interface. A uniform layer by layer transfer has been demonstrated by the linear increase of maximum absorption with increasing film thickness. A red shift observed in the UV-Vis spectra of the Langmuir-Blodgett (LB) films revealed a possible J-type aggregation of molecules. LB films have also been characterized by Fourier Transform infra Red (FTIR) spectroscopy. (C) 1998 Elsevier Science S.A. All rights reserved.