Synthesis of Dye and Heat-Treated Halloysite Nanotube Hybrids and their Color Properties and Chemical Resistances

A series of new organic–inorganic nanohybrids were successfully prepared by using Congo red and heat-treated halloysite clays. The results show that an increase in calcination temperature leads to the reduction of lightness ([Formula: see text]*) and color hue ([Formula: see text]*, [Formula: see text]*). The hybrids prepared, respectively, with 400 ∘ C treated and 500 ∘ C treated halloysites have the same order of HNO[Formula: see text] with respect to the acid resistance. The hybrid with a light red hue can be obtained by alkali treatment when halloysite calcined at higher temperature was used as a host. There exists a strong host–guest interaction between nanotubes and Congo red anions. The leaching of aluminum in the clay has a decisive influence on the acid/alkali resistance of the hybrid.