In Situ Synthesis of Layered Double Hydroxide (LDH)/Polyelectrolyte Intercalation Compounds

In Situ Synthesis of Layered Double Hydroxide (LDH)/Polyelectrolyte Intercalation Compounds

Jingfang Yu, Johnathan E. Sims, Jarett C. Martin, Luyi Sun*

Department of Chemistry and Biochemistry & Materials Science, Engineering, and Commercialization Program, Texas State University-San Marcos, San Marcos, TX 78666

Abstract

Two types of polyelectrolytes: poly(acrylic acid, sodium) (PAAS) and poly(sodium 4-styrenesulfonate) (PSSS) have been incorporated into the positively charged sheets of layered double hydroxides (LDH) [M²⁺_1-xM³⁺_x(OH)₂]^x+[A^p-_x/p]^x+•mH₂O through an in situ hydrothermal reaction to form layered intercalation compounds. The synthesized compounds were systematically studied and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (SEM), and thermogravimetric analysis (TGA). The resultant compounds exhibited a much higher interlayer distance, which are ca. 20 Å and 19 Å for LDH/PSSS and LDH/PAAS, respectively, compared with the pristine LDH. The XRD and FT-IR results were consistent and confirmed the formation of an intercalated structure. The SEM images showed the morphological changes with different weight percentages of polyelectrolytes incorporated. The TGA results showed that the intercalated polyelectrolytes were more thermally stable than the free polyelectrolytes.