Multilayer X(2) films from porphyrin chromophores by LBK processing

Electrooptic films based on a new class of porphyrin chromophores with exceptionally large molecular first hyperpolarizabilities are begin developed. These chromophores feature donor and acceptor groups linked to the porphyrin macrocycle at the 5- and 15-meso positions through intervening ethynyl moieties. We report herein preliminary result that describe the ambient temperature assembly of ordered, electrooptic films using the Langmuir-Blodgett-Kuhn method. The facile formation of such films was mae possible by the preparation of amphiphilic chromophores containing hydrophobic aliphatic substituents to enhance the polar alignment at the air-water interface. Second harmonic generation and UV-Vis absorption were used to characterize the films as a function of the number of layers deposited. Polar films containing up to 10 layers were made by simple Y-type homolayer deposition, and up to six layers by the Y- type heterolayer method in which the porphyrin layers were interleaved with poly(t-butyl methacrylate). The polar order in these films relaxed exponentially. Ionic structures are recommended for improved stability.