Surface and interfacial properties of polymer-intercalated layered double hydroxide nanocomposites

摘要

The surface and interfacial properties of the layered double hydroxide (LDH) phase Mg_6Al_2(OH)_16CO_3 4H_2O (LDHCO3) and its nanocomposites with poly(styrenesultbnate) (LDHPSS) and poly(vinylsulfonate) (LDHPVS) were characterized by X--ray diffraction, thermo- gravimetric analysis, Fourier transform infrared spectroscopy, transmission electron microscopy, He pycnometry, and electrophoretic light scattering. Polymer incorporation within the inter--gallery space resulted in a shift of the d_003 reflection from 7.7 A (LDHCO3) to 12.7 A (LDHPVS) and 21 A (LDHPSS). This increase in basal plane spacing caused the density of the LDH samples to decrease from 2.05 g/cm~3 (LDHCO3) to 1.83 and l.4l g/cm~3 for LDHPVS and LDHPSS nanocomposites, respectively. LDHCO3 exhibited a positive electrophoretic mobility over the pH range from 4-ll with an isoelectric point (iep) at pH ll. However, the LDH nanocomposites displayed a negative electrophoretic mobility over the measured pH range, indicating that the