Formation of aggregates of DNA molecules chemisorbed on the organized films of comb copolymers containing s-triazine

Adsorption behavior of DNA molecules on comb copolymers containing 2-vinyl-4,6-diamino-1,3,5-triazine (VDAT) at the air/water interface and their molecular arrangement were investigated using surface pressure–area (π–A) isotherms, infrared (IR) spectroscopy, polarized UV–vis spectroscopy, and atomic force microscopy (AFM). Newly hydrogenated and fluorinated binary comb copolymers containing VDAT as an adsorption template were synthesized by radical copolymerization. Based on the results of the π–A isotherm of the monolayer on DNA aqueous solution, an increase in the value of molecular area per VDAT unit corresponds to an area of 20 Å2. The IR spectrum of the transferred Langmuir–Blodgett (LB) multilayer indicates adsorption of DNA molecules by hydrogen bonding to the copolymer templates. AFM images show that the circular domains have 50–60 nm diameters. Adsorbed DNA molecules showed an absorption band at 260 nm and emitted fluorescence at 400 nm. Consistent with the results of polarized UV–vis spectroscopy, these absorption bands indicate weak polarized dependency. In addition, emission bands in the fluorescence spectrum of DNA adsorbed to the copolymer film showed red shift and became sharper than those of the DNA solution.