Surface and Interfacial Properties of
Polymer-Intercalated Layered Double Hydroxide Nanocomposites

O. C. Wilson, Jr.,a T. Olorunyolemi,a A. Jaworski,a L. Borum,a D. Young,a A. Siriwat,a
E. Dickens,b C. Oriakhi,c M. Lernerc

a University of Maryland, Department of Materials and Nuclear Engineering, College Park, MD 20742-2115, USA
b Eleanor Roosevelt High School, Greenbelt, MD 20770, USA
c Department of Chemistry and Center for Advanced Materials Research, Oregon State University,
Corvallis, OR 97331-4003, USA

Applied Clay Science 16, 265-279 (1999)

ABSTRACT. The surface and interfacial properties of the layered double hydroxide (LDH) phase Mg6Al2(OH)16CO3 · 4H2O (LDHCO3) and its nanocomposites with poly(styrensulfonate) (LDHPSS) and poly(vinylsulfonate) (LDHPVS) were chracterized by X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, transmission electron microscopy, He pycnometry, and electrophoretic light scattering. Polyer incorporation within the inter-gallery space results in a shift of the d003 reflection from 7.7 Å (LDHCO3) to 12.7 Å (LDHPVS) and 21 Å (LDHPSS). This increase in basal plane spacing caused the density of the LDH samples to decrease from 2.05 g/cm3 (LDHCO3) to 1.83 and 1.41 g/cm3 for LDHPVS and LDHPSS nanocomposites, respectively. LDHCO3 exhibited a positive electrophoretic mobility over the pH range from 4-11 with an isoelectric point (iep) at pH 11. However, the LDH nanocomposites displayed a negative electrophoretic mobility over the measured pH range, indicating that the surface properties of the LDH nanocomposites were dominated by negatively charged sulfonate groups from absorbed polymer molecules.

Research was supported by the Air Force Office of Scientific Research (Grant F496209610457).