Dynamics of liquid crystalline gelation of DNA

DNA liquid crystalline gel (LCG) films have been prepared by immersing DNA aqueous borate solutions sandwiched between two circular glass plates into cobalt chloride solutions. The time courses of the thickness, the weight fractions of DNA and cobalt cations, and the birefringence and turbidity of the film consisted of outer DNA LCG and inner DNA amorphous gel or solution have been measured. To clarify the mechanism of the process forming LCG, the theory based on the nonequilibrium thermodynamics with "moving boundary picture" [Langmuir 2005, 21, 8155-8160] was modified, and the results were analyzed by the modified theory. It was found that the growth process of DNA LCG consists of two dynamics: cobalt cation diffusion-limited process at the early stage and the DNA circumstance change limited process at the later stage.