Most of the humidity sensors practically used are based on the change ill e
lectrical properties of polymers or ceramics with humidity. They are either
resistive-type or capacitive-type sensors. Various chemical modifications
of polymeric materials have been utilized to improve the properties of sens
ors such as sensitivity, hysteresis, long-term stability, durability in unf
avorable atmospheres such as dewdrops or vapors' of volatile organic compou
nds(VOC), etc. This paper overviews the novel methods of chemical modificat
ion which have been proposed by the authors.