Standard porosimetry was used to study the pore structure of polyanili
nes (PAn) synthesized both electrochemically (on platinum and graphiti
c carbon cloths) and chemically. For the first time the structure of P
An was analyzed in water, i.e., under conditions approaching those enc
ountered in the use of these electrodes. It was found that an importan
t swelling of PAn occurs in water; it is attended by an increase in sp
ecific surface area. Thus, the total surface area of pores with radii
above 1.0 nm increases by a factor of two to ten. The specific surface
areas of these pores in water are 50-100 m2/g, those of the micropore
s are 20-120 m2/g. It was found that the structure of PAn changes duri
ng doping and undoping. The structure of PAn samples synthesized chemi
cally was found to differ importantly from that of samples synthesized
electrochemically.