Abstract
Hydroxyethyl cellulose (HEC) film has been prepared by casting technique. The prepared sample has been treated with nitrogen plasma at different exposure times. The optical absorption was recorded at room temperature in the wavelength range of 200–800nm. Absorbance fitting procedure curves revealed a direct allowed transition with optical band gap, Eopt, of 4.9eV for pristine film, and this value decreases to 4.30eV for 20min plasma treatment time. The band tail values (Ee) were found to be increased under plasma time treatment from 1.74eV in case of the pristine film to 2.20eV for 20min. The dispersion of refractive index and complex dielectric constants under plasma treatment was also studied. Variation of color parameters under effect of the plasma treatment is analyzed in the framework of CIE L*U*V* color space.
Absorbance spectra of hydroxyethyl cellulose film under different plasma treatment times. [Display omitted]
•Hydroxyethyl cellulose film is prepared by casting technique.•Prepared film is exposed to nitrogen plasma at different times.•Refractive index of film is modulated via treatment of plasma.•Optical band gap of film is changed effectively with plasma treatment.