The CV peak in the current registered for pH 1.73 is over two times higher, compared to pH 7.48 and 7.97 (Fig. ), the effect is not as prominent in less acidic media. This effect should be correlated with inducing more positive charges, i.e. the formation of more -NH3 + species, on the CS chains at higher protonation states, as was predicted from electrostatic potential maps in Fig. . Repulsive forces between positively charged polymeric chains can result in a more accessible free volume for redox species to diffuse into, thereby increasing the D values (for CS HM increase from 3.8 x10 -7 in pH 7.48 to 2.38 x10 -6 for pH 1.95).