Two kinds of optically transparent thin films with photochromic properties have been fabricated based on co-intercalation of 4-(4-anilinophenylazo)benzenesulfonate(AO5)and sodium dodecylbenzene sulfonate(SDS)into the galleries of a ZnAl layered double hydroxide(LDH)by two synthetic methods:solvent evaporation and in situ crystallization.The two films possess LDH crystallites in different orientations relative to the substrates depending on their fabrication method:horizontal and vertical.The relationship between the photochromic behavior of the interlayer chromophore and the orientation of the LDH crystallites is studied thoroughly.The orientation of the LDH crystallite influences the photochromic behavior of the films.The films exhibited different absorption and wettability characteristics,providing the potential for application of dye-LDH films as photochromic materials and light sensitive switches.
NiFe_(2)O_(4) nanoparticles(<10 nm)embedded in a NiO matrix have been fabricated by calcining the corresponding Ni^(Ⅱ)Fe^(Ⅲ)-layered double hydroxide(LDH)precursors at high temperature(500℃).Compared with the NiFe_(2)O_(4)/NiO nanocomposite obtained by calcination of a precursor prepared by a traditional chemical coprecipitation method,those derived from NiFe-LDH precursors show much higher blocking temperatures(TB)(~380 K).The enhanced magnetic stability can be ascribed to the much stronger interfacial interaction between NiFe_(2)O_(4) and NiO phases due to the topotactic nature of the transformation of the LDH precursor to the NiFe_(2)O_(4)/NiO composite material.Through tuning the Ni^(Ⅱ)/Fe^(Ⅲ) molar ratio of the NiFe-LDH precursor,the NiFe_(2)O_(4) concentration can be precisely controlled,and the TB value as well as the magnetic properties of the final material can also be regulated.This work represents a successful example of the fabrication of ferro(ferri)magnetic(FM)/antiferrimagnetic(AFM)systems with high magnetic stability from LDH precursors.This method is general and may be readily extended to other FM/AFM systems due to the wide range of available LDH precursors.
