Reconstitution of cutin monomers on smectite surfaces: adsorption and esterification

- Adsorption of cutin monomers is affected by the type of exchangeable cation.
- Cutin monomers were esterified and reconstituted on the surface of smectites.
- Smectite surfaces promote the oligomerization of adsorbed cutin monomers.
- Oligomerization was enhanced by the surface iron.

This paper focuses on the physico-chemical interactions of cutin monomers with clay smectites. Adsorption of cutin monomers was measured, and esterification and reconstitution were studied using Fourier transformed infrared spectrometry (FTIR), X-ray diffraction (XRD) and mass spectrometry (MS) analyses. Adsorption of a common cutin monomer, ω-dihydroxypalmitic acid (diHPA) to smectite was found to be affected by its interactions with exchangeable cations. Inner-sphere complexation was observed for Fe3 +-montmorillonite, and nontronite. Outer-sphere complexes were observed for Ca2 +- and Wyoming Na+-montmorillonite. XRD measurements showed that cutin monomers were intercalated between smectite layers, and MS results demonstrated their enhanced esterification on the smectite surfaces (as compared to monomer solution). This study suggests that cutin monomers can be reconstituted and esterified on the smectite surfaces to form stable organo-mineral complexes.