Abstract: Langmuir-Blodgett films having hydrophobic surfaces are chemically modified to convert the hydrophobic surfaces to hydrophilic surfaces for immobilization of active moieties having bioactive, immunoactive, thermoactive, electroactive, optoactive or redoxactive properties. Langmuir-Blodgett films having a hydrophobic surface of omega unsaturated covalent bonds are formed from an amphiphilic, bifunctional surface active material having a hydrophobic tail group bearing an omega terminus of double or triple bonded unsaturation. The amphiphilic material may be fatty acids, phospholipids or porphyrins, and is preferably omega-tricosenoylamide or omega-tricosenoic acid. Chemical modification is carried out by exposing the hydrophobic surface to a reagent such as alkaline or acidic potassium permanganate, potassium dichromate or osmium tetroxide which oxidizes the omega unsaturated covalent bonds to provide hydrophilic groups such as hydroxyl or carboxylic acid groups.