We have investigated the effect of solvent and carbon black structure on the electric resistance of the vapor sensor composite materials prepared by dispersing carbon black (CB) into a poly(ethy1ene oxide) (PEO) matrix.
PEO polymers having molecular ...
We have investigated the effect of solvent and carbon black structure on the electric resistance of the vapor sensor composite materials prepared by dispersing carbon black (CB) into a poly(ethy1ene oxide) (PEO) matrix.
PEO polymers having molecular weights of 2 ×10^(6) and 4 ×10^(6) were selected to be the polar crystalline polymers.
Carbon black, with particle sizes ranging from 45 to 300 nm, was used as a conductive material.
After PEO was dissolved completely in tetrahydrofuran at 5O℃, CB was added and stirred into the polymer solution uniformly.
A conductive PEO film containing CB was made by casting it on a glass plate.
The electrical resistance of the conductive PEO film in various solvent vapors, such as acetone, benzene, ethanol, isopropyl alcohol, and tetrahydrofuran, was measured in a glass tube containing pure solvent at the bottom.
We found that the electrical resistance of the PEO/CB composite increased drastically in polar-solvent vapor, but had a low response to a non- and low-polar-solvent vapor.
A PEO film filled with CB of large particle size exhibited a high response of its electrical resistance against vapors.