HUMIDITY SENSORS USING CHEMICALLY-MODIFIED POLYMERIC MATERIALS

Various chemical modifications of polymers are proposed to meet the requirement for use in two types of humidity sensors, i.e. the resistive type and the capacitive type. Hydropbilic polymers are adequate to prepare the resistive type sensor, but they must be modified in order to be insoluble in water. Three methods, i.e. graft polymerization, cross-linking and IPN formation, have been proposed. For the capacitive type sensor, the cross-linking of hydrophobic polymers has been proposed to modify them so they will not deform in the vapors of organic solvents.