Summary report on AFRL studies of the optical and electrical properties of biopolymers using salmon DNA

The Materials and Manufacturing Directorate of the Air Force Research Laboratory (AFRL) began studies of deoxyribonuclaic acid (DNA) as a polymer material in 2001 due to the availability of multi-gram quantities of 98% pure DNA extracted from Japanese salmon waste products. The research studies that followed explored the electrical, optical and electrooptical characteristics of thin films of DNA combined with the surfactant hexacytltrimethylammonium chloride making the resulting DNA-CTMA complex soluble in most polar solvents and insoluble in water. The films were produced mainly by spin coating although other techniques were also used. The focus was to measure the fundamental properties, such as volume electrical resistivity, dielectric constant, refractive index and thermal conductivity, and to explore various applications using test device configurations such as an optical modulator, OFET, OLED and energy storage capacitor fabricated using DNA-CTMA. The initial high molecular weight of 2,000 to >8,000 kDa was reduced by high power ultrasonic treatment, which provided molecular weight materials from 1,000 down to similar to 200 kDa. These lower molecular weight materials revealed changes in some properties of the DNA-CTMA material. This paper brings together the results of these studies to show the potential of DNA as a polymer material.