A carboxyethyl substituted azacrown ether derivative (CSAE) was intercalated as a second host into a parent host of well-crystallized crystal of Mg-Al layered double hydroxide (MgAl-LDH) by a CSAE/NO 3 ion-exchange reaction. The influence of intercalation temperature on the structures and compositions of CSAE-LDH nanocomposites was investigated. The composites obtained at the temperatures below 70 °C had almost the same CASE contents and layered structures with a basal spacing of about 1.6 nm, corresponding to the vertical orientation of CSAE plane to the LDH layer. The chemical analysis showed that a considerable amount of CO 3 2-(with CO 3 2-/CSAE molar ratio of 1.4) was incorporated in the interlayer of LDH. The CSAE content decreased while CO 3 2content increased with an increase of the intercalation temperature in the region above 70 °C. At 100 °C, a second staging phase of 2.33 nm appeared, attributed to the ordered stacking of the 1.6 nm phase and a 0.77 nm phase produced by the CO 3 2-/CSAE exchange. At higher temperatures, a new phase with a basal spacing of 1.18 nm appeared, which corresponds to the tilt/twisted orientation of CSAE anions in the interlayer. The other second staging phase of 2.08 nm appeared obviously at 150 °C, due to the regular stacking of the 1.18 and 0.77 nm phases. The adsorptive properties for transition metal ions were studied using the 70 and 150 °C reacted composites. The 70 °C reacted one showed higher adsorptivity toward transition metal ions; the adsorptive capacity increased in the sequence of Cu 2þ > Ni 2þ > Co 2þ > Zn 2þ , and distribution coefficient for Cu 2þ was markedly higher than those for the other ions. However, the 150 °C reacted one showed little adsorptivity toward these ions. The adsorption for transition metal ions was accompanied by the intercalation of nearly equivalent amount of nitrate ions. This shows that the interlayer CSAE ions in the 1.6 nm phase act as a second host, but those in the 1.18 nm phase do not.

Nanosheets exfoliated from layered inorganic crystals can be regarded as inorganic macromolecules. Herein, coassembly of layered double hydroxide (LDH) nanosheets with carboxymethyl cellulose (CMC) was presented. CHN analysis, XRD, FTIR, TG-DSC and SEM were employed to characterize the coassembly process. The results showed that the colloidal suspension of the exfoliated MgAl−LDH nanosheets in formamide were restacked when in contact with water. Nevertheless, CMC can prevent the colloidal state from flocculation even after all included formamide molecules were removed by water, that is the interaction of CMC molecules and the nanosheets stabilized the dispersion in aqueous media. Drying at 40 °C led the nanosheets and CMC to restack to a layered nanocomposite with a basal spacing of 1.75 nm, indicating a bilayer arrangement of CMC in the interlayer. The thermal degradation temperature of CMC in the composite was raised by about 160 °C.

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Water-soluble tetrasodium p-sulfonatothiacalix[4]arene (TCAS) was intercalated into MgAl-LDH using an osmotic swelling/restoration reaction of the LDH in formamide. The restoration process was investigated in detail. The arrangement of TCAS in the interlayer can be controlled through adjusting the area per unit charge (S charge ) of TCAS. When S charge (TCAS) < S charge (LDH), monolayer (basal spacing, d basal , 1.30 nm) and alternating "up-down" antiparallel (d basal , 1.54 and 1.45 nm) arrangements were obtained. When S charge of TCAS was increased by forming an Ag þ complex, bilayer arrangement (d basal , 2.12 nm) of TCAS(Ag) was formed. This swelling/restoration reaction took place, and the composites retained the morphology of the LDH precursor. The thermal stability of TCAS in the composites was remarkably enhanced, and the "up-down" antiparallel arrangement of TCAS had the highest increase of thermal stability.