Figure 1
Swelling curves and the development of the logarithmic volume and absorbance. 
, where V0 is the initial volume before swelling, V
p
the final volume after swelling, and V (t) the volume at time t. Similarly, 
, where A0 is the initial, A
p
the final absorbance, and A(t) the absorbance at time t. Both L
vol
(t) and L
abs
(t) were obtained from the experimental data. The vertical dotted lines show the end of the swelling, the slanted dashed lines are the best linear approximations to the curves.