Polypyrrole/poly(methylmethacrylate) blend as selective sensor for acetone in lacquer.

A film of alpha-naphthalene sulfonate-doped polypyrrole/poly(methylmethacrylate), PPy/alpha-NS(-)/PMMA, obtained from solution mixing was successfully used as sensing material for acetone vapor in lacquer with a high degree of selectivity based on electrical conductivity over acetic acid and a high degree of stability over the humidity change. Compared with pure PPy/alpha-NS(-), the selectivity ratio of acetone/acetic acid response of PPy/alpha-NS(-)/PMMA blend with a PMMA/PPy weight ratio of 3.0 was ca. 3.9 times higher. The film was found to be insensitive to moisture unless the relative humidity (RH) was lower than 20% RH in which the selectivity ratio of acetone/acetic acid response was enhanced. The time required to reach the equilibrium for acetone exposure was found to increase slightly with increasing humidity.