Fig. 4

Schematic representation of the chemical modification of pullulan showing the addition of the tertiary amine, dimethylaminoethyl (DMAE) chloride a and FT-IR spectra of pullulan before after synthesis highlighting the qualitative changes in the spectral intensity correlating to the new functional groups b. The reaction was performed using an adapted version from San Juan et al.³¹ Five gram of Pullulan (Carbosynth, 200 kDa) was dissolved in 25 ml of distilled water and mixed with a 25 mL 10 M sodium hydroxide solution to activate the pullulan hydroxyl functions. Then, 35gm of 2-chloro-N,N dimethylethylamine hydrochloride was added to the mixture and left stirring at 60 °C for 1 h. After the reaction was completed, the mixture was washed four times with 50 ml diethyl ether and after was diluted in water to a concentration of 10 mgmL⁻¹ and adjusted to pH 7 using HCl