Abstrakt
The present contribution reports the single-step preparation of new type of soft macroporous conducting cryogels, a special type of hydrogels. Polyaniline/poly(vinyl alcohol) cryogel was prepared by the oxidation of aniline hydrochloride in frozen reaction mixtures, in ice, containing a supporting polymer, poly(vinyl alcohol).
The cryogel used for illustration contained of polyaniline, poly(vinyl alcohol) and 93 wt % of aqueous phase. It was macroscopically homogeneous and it had macroporous structure with average pore size of approximate to 100 mu m.
The conducting polyaniline phase was fibrillary. The molecular structure of polyaniline was confirmed by Raman spectroscopy.
The conductivity of cryogel was 0.004 S cm(-1) in water and 0.105 S cm(-1) in 0.1 M sulfuric acid. It still increased to 0.29 S cm(-1) when the content of monomer increased five times.
Because of the contribution of electronic transport, the conductivity of cryogel was always higher than the ionic conductivity of aqueous phase used for its penetration. The conductivity of freeze-dried cryogel was 0.003 S cm(-1).
Viscoelastic and mechanical properties, controlled mainly by the conducting polymer phase, have been assessed and demonstrated good mechanical integrity and feasibility of potential applications.