Synthesis, characterization and release of a-naphthaleneacetate from thin films containing Mg/Al-layered double hydroxide

• Intercalated NAA into the Mg/Al–NO3–LDH by ion-exchange method.
• Thin films were made by the LBL method with polymers and Mg/Al–NAA–LDH.
• The films were put into various solutions, and discuss the release mechanism.
• The mechanism accorded with first-order kinetics.

An active agent a-naphthaleneacetate (NAA), a plant growth regulator was intercalated into the layered double hydroxides Mg/Al–LDH by ion-exchange method. And we prepared the films by the method of layer-by-layer self-assembly with Cationic Polyacrylamide, Polyacrylic acid sodium and LDH. The obtained compounds were characterized by X-ray diffractometer (XRD), Fourier transform infrared (FT-IR) and Scanning Electron Microscopy (SEM) techniques. The XRD datas demonstrated the guest size and the orientation of anions between the layers was determined. After intercalation, it was proposed that the NAA anions were accommodated in the interlayer region as a bilayer of species with the carboxyl attaching to the upper and lower layers. The FT-IR of the powder from film shows that Mg/Al–NAA–LDH was absorbed on the quartz glass. The film was putted into various solutions, and the release of NAA from the film showed obvious release effect. The release mechanism may be based on the dissolution and ion-exchange process according to first-order kinetics.

The data obtained from the NAA released into the aqueous solution at different temperature and pH solutions fitted to the first-order kinetic. The kinetic indicated that the release process was controlled by the course of dissolution and ion-exchange process.Figure optionsDownload as PowerPoint slide