Data from: Holographic sol-gel monoliths: optical properties and application for humidity sensing

Sol–gel monoliths based on SiO2, TiO2 and ZrO2 with holographic colourful
diffraction on their surfaces were obtained via a sol–gel synthesis and
soft lithography combined method. The production was carried out without
any additional equipment at near room temperature and atmospheric
pressure. The accurately replicated wavy structure with nanoscale size of
material particles yields holographic effect and its visibility strongly
depends on refractive index (RI) of materials. Addition of multi-walled
carbon nanotubes (MWCNTs) in systems increases their RI and lends
absorbing properties due to extremely high light absorption constant.
Further prospective and intriguing applications based on the most
successful samples, MWCNTs-doped titania, were investigated as reversible
optical humidity sensor. Owing to such property as reversible resuspension
of TiO2 nanoparticles while interacting with water, it was proved that
holographic xerogels can repeatedly act as humidity sensors. Materials
which can be applied as humidity sensors in dependence on holographic
response were discovered for the first time.