Lewis acid pigment solubilization

     Applications of pigments for coatings, printing and information storage are widespread, but the fabrication of thin films of pigments is difficult because of their insoluble nature. Dyes, on the other hand, are easier to manipulate. Research at the Xerox Corporation has shown that Lewis acid complexes can be utilized to solubilize and lay down thin films of certain pigments. For example, the photosensitive perylene derivative shown below forms an adduct with AlCl₃:

Complex formation occurs in MeNO₂ solution and the solution is then applied to the surface to be coated. Washing with water removes the Lewis acid leaving a thin film of the photosensitive pigment. The Lewis acid pigment solubilization (LAPS) technique has been used to fabricate multilayer photoconductors and appears to have a promising technological future.